Efficiency of different strains of Trichoderma on the control of Sclerotinia sclerotiorum, Sclerotium rolfsii and Sclerotium cepivorum

The aim of this work was to verify the efficiency of different isolates of Trichoderma spp.on the control of Sclerotiniasclerotiorum, Sclerotiumrolfsii and Sclerotiumcepivorum, and the influence they pose on the conidia production of Trichoderma spp.For mycelial growth, discs with inoculum of phytopathogens were placed on the center of the Petri dishes followed by the addition of two Trichodermasp. discs on the opposite sides of the plate after 24hours. Every 12hoursdata were collected from colonies diameters and used for the analyses of Mycelial Growth Index (MGI) and Area Under the Curve of Mycelial Growth (AUCMG). The analyses were performed by a completely randomized design with two controls, a negative one without Trichodermasp. and one with acommercial strain of Trichodermaharzianum. Spore solution for evaluation of conidia production were made by adding 10 mL of distilled water and scratching the surface of the colonies. For S. cepivorum, all Trichoderma spp. strains reduced both indexes tested. However, while for MGI S. sclerotiorum also presented some reduction on the growth rate, the total area of this fungus was not affected. Sclerotiumrolfsii strains of Trichodermasp. from Lages and Curitibanosshowed an effect on the reduction of AUCMG of this fungus, although none of the Trichodermaaffected the growth rate of this phytopathogen. On the presence of S. sclerotiorumand S. cepivorum, none of the Trichodermaspp. showed any difference on conidia production when compared among themselves, nonetheless we did notice that on the presence of S. cepivorum, the strain from Rio do Sul retained its reproductive ability compared to control. Results obtained from this research can demonstrate the importance of biocontrol agents against different plant pathogens since it might have a specific antagonist-pathogen relation.(AU)

Biological control of Meloidogyne javanica in bean plants by Hohenbuehelia spp. and Trichoderma koningiopsis

Nematode control strategies are limited and alternative control is demanded. The main aim was to evaluate control potential of Hohenbuehelia spp. (Hohenbuehelia mastrucata, Hohenbuehelia barbatula, Hohenbuehelia bullulifera, Hohenbuehelia portegna, Hohenbuehelia petaloides and Hohenbuehelia paraguayensis) and Trichoderma koningiopsis against Meloidogyne javanica in bean plants in greenhouse. The parameters evaluated were the number of galls and egg masses which were evaluated in three root regions: basal, intermediate and tip; nematode reproduction factor; vegetal growth parameters (plants height on V1, V2, V4, and R5 growth stages, root length, dry weight of root and aerial part dry weight); Treatments were composed by individual interactions of each fungal isolate with 4,000 eggs of M. javanica, having a total control (bean) and a partial control (bean + nematode) arranged in completely randomized design with four repetitions. Data were tested by Scott­Knott (5%). For vegetal growth parameters, there was only significance for dry weight of roots. All species were able to control nematodes.

Biological control of Meloidogyne javanica in bean plants by Hohenbuehelia spp. and Trichoderma koningiopsis

ABSTRACT Nematode control strategies are limited and alternative control is demanded. The main aim was to evaluate control potential of Hohenbuehelia spp. (Hohenbuehelia mastrucata, Hohenbuehelia barbatula, Hohenbuehelia bullulifera, Hohenbuehelia portegna, Hohenbuehelia petaloides and Hohenbuehelia paraguayensis) and Trichoderma koningiopsis against Meloidogyne javanica in bean plants in greenhouse. The parameters evaluated were the number of galls and egg masses which were evaluated in three root regions: basal, intermediate and tip; nematode reproduction factor; vegetal growth parameters (plants height on V1, V2, V4, and R5 growth stages, root length, dry weight of root and aerial part dry weight); Treatments were composed by individual interactions of each fungal isolate with 4,000 eggs of M. javanica, having a total control (bean) and a partial control (bean + nematode) arranged in completely randomized design with four repetitions. Data were tested by ScottKnott (5%). For vegetal growth parameters, there was only significance for dry weight of roots. All species were able to control nematodes.

Effect of chitosan on the mycelial growth of Fusarium oxysporum, Rhizoctonia solani and Trichoderma spp / Efeito da quitosana no crescimento micelial de Fusarium oxysporum, Rhizoctonia solani e Trichoderma spp

Fungicides, often used in conventional farming systems, can harm humans, animals and damage the environment. Chitosan, which is extracted from the crustacean shell, has shown to be a harmless and cheap alternative to fungicides. This study aimed to test the inhibitory effect of chitosan on the mycelial growth of Fusarium oxysporum, Rhizoctonia solani and Trichoderma spp. Different concentrations of chitosan (0, 1, 2, 4, 8 and 16%) were supplemented to 1% acetic acid Potato Dextrose Agar (PDA). The fungi were inoculated in the center of the plates, incubated at 25 °C, with or without a 12-hour photoperiod. Daily measurements were performed in two transverse diameters until the mycelium reached the edges of the Petri dish. Fusarium oxysporum mycelial growth was significantly inhibited by chitosan at concentrations 1, 2, 4, and 8%, on the 4th, 5th and 6th evaluation days, in a 12-hour photoperiod. However, for Rhizoctonia solani, there was no reduction on mycelial growth. Trichoderma spp. presented the greatest mycelial reduction, in both light schemes, in all the concentrations evaluated, on days one, two and three. The results indicate that the mycelial growth of Fusarium oxysporum and Trichoderma spp. were inhibited by chitosan. Although, the combined use of chitosan and Trichoderma spp. as biocontrol agents of phytopathogens is not indicated.

Os fungicidas, frequentemente utilizados em sistemas agrícolas convencionais, podem prejudicar seres humanos, animais e danificar o meio ambiente. A quitosana, extraída da casca do crustáceo, tem se mostrado uma alternativa inofensiva e barata aos fungicidas. Este trabalho teve como objetivo testar o efeito inibitório da quitosana sobre o crescimento micelial de Fusarium oxysporum, Rhizoctonia solani e Trichoderma spp. Diferentes concentrações de quitosana (0,1, 2, 4, 8 e 16%) foram adicionadas em Batata Dextrose Agar (BDA) preparado em 1% de ácido acético. Os fungos foram inoculados no centro das placas,incubados a 25 °C, com ou sem fotoperíodo de 12 horas. Medições diárias foramrealizadas em dois diâmetros transversais até o micélio atingir as bordas da placade Petri. O crescimento micelial de Fusarium oxysporum foi significativamente inibido pela quitosana nas concentrações 1, 2, 4 e 8%, nos dias 4, 5 e 6 deavaliação, em fotoperíodo de 12 horas. No entanto, para Rhizoctonia solani não houve redução no crescimento micelial. Trichoderma spp. apresentou a maior redução micelial, em ambos os esquemas de luz, em todas as concentrações avaliadas, nos dias um, dois e três. Os resultados indicam que o crescimento micelial de Fusarium oxysporum e Trichoderma spp. foram inibidos pela quitosana. Assim, o uso combinado de quitosana e Trichoderma spp. como agentes de biocontrole de fitopatógenos não é indicado.

Effect of chitosan on the mycelial growth of Fusarium oxysporum, Rhizoctonia solani and Trichoderma spp / Efeito da quitosana no crescimento micelial de Fusarium oxysporum, Rhizoctonia solani e Trichoderma spp

Fungicides, often used in conventional farming systems, can harm humans, animals and damage the environment. Chitosan, which is extracted from the crustacean shell, has shown to be a harmless and cheap alternative to fungicides. This study aimed to test the inhibitory effect of chitosan on the mycelial growth of Fusarium oxysporum, Rhizoctonia solani and Trichoderma spp. Different concentrations of chitosan (0, 1, 2, 4, 8 and 16%) were supplemented to 1% acetic acid Potato Dextrose Agar (PDA). The fungi were inoculated in the center of the plates, incubated at 25 °C, with or without a 12-hour photoperiod. Daily measurements were performed in two transverse diameters until the mycelium reached the edges of the Petri dish. Fusarium oxysporum mycelial growth was significantly inhibited by chitosan at concentrations 1, 2, 4, and 8%, on the 4th, 5th and 6th evaluation days, in a 12-hour photoperiod. However, for Rhizoctonia solani, there was no reduction on mycelial growth. Trichoderma spp. presented the greatest mycelial reduction, in both light schemes, in all the concentrations evaluated, on days one, two and three. The results indicate that the mycelial growth of Fusarium oxysporum and Trichoderma spp. were inhibited by chitosan. Although, the combined use of chitosan and Trichoderma spp. as biocontrol agents of phytopathogens is not indicated.(AU)

Os fungicidas, frequentemente utilizados em sistemas agrícolas convencionais, podem prejudicar seres humanos, animais e danificar o meio ambiente. A quitosana, extraída da casca do crustáceo, tem se mostrado uma alternativa inofensiva e barata aos fungicidas. Este trabalho teve como objetivo testar o efeito inibitório da quitosana sobre o crescimento micelial de Fusarium oxysporum, Rhizoctonia solani e Trichoderma spp. Diferentes concentrações de quitosana (0,1, 2, 4, 8 e 16%) foram adicionadas em Batata Dextrose Agar (BDA) preparado em 1% de ácido acético. Os fungos foram inoculados no centro das placas,incubados a 25 °C, com ou sem fotoperíodo de 12 horas. Medições diárias foramrealizadas em dois diâmetros transversais até o micélio atingir as bordas da placade Petri. O crescimento micelial de Fusarium oxysporum foi significativamente inibido pela quitosana nas concentrações 1, 2, 4 e 8%, nos dias 4, 5 e 6 deavaliação, em fotoperíodo de 12 horas. No entanto, para Rhizoctonia solani não houve redução no crescimento micelial. Trichoderma spp. apresentou a maior redução micelial, em ambos os esquemas de luz, em todas as concentrações avaliadas, nos dias um, dois e três. Os resultados indicam que o crescimento micelial de Fusarium oxysporum e Trichoderma spp. foram inibidos pela quitosana. Assim, o uso combinado de quitosana e Trichoderma spp. como agentes de biocontrole de fitopatógenos não é indicado.(AU)

Creole bean seeds microbiolization with doses of Trichoderma harzianum / Microbiolização de sementes de feijão crioulo com doses de Trichoderma harzianum

In the search for improved yields, seed treatment by microbiolization has been used as an alternative to chemical treatment. The objective was to verify the physiological and sanitary quality of creole bean seeds, var. Chumbinho, after microbiolization with doses of a commercial product (c.p.) with Trichoderma harzianum (strain ESALQ-1306). The treatments were: T1) 100 mL c.p./100 kg seeds; T2) 150 mL c.p.; T3) 200 mL c.p.; T4) 200 mL of chemical treatment (c.p., 250 g L-1 fipronil + 25 g L-1 pyraclostrobin + 225 g L-1 thiophanate-methyl); and T5) control (without coating of seeds). The tests were: sanitary test (blotter test); germination and first count; accelerated aging, cold germination without soil, speed of germination rate (SGR), seedling shoot and root lengths, and emergence of seedlings in a greenhouse. T. harzianum controlled Aspergillus spp., Penicillium spp. and Fusarium oxysporum. With 100 mL c.p. of T. harzianum dose had better results for the germination and vigor, and this dose it is an alternative to chemical treatment in creole bean seeds.(AU)

Na busca por melhores rendimentos, o tratamento de sementes por microbiolização tem sido utilizado como alternativa ao tratamento químico. Objetivou-se verificar a qualidade fisiológica e sanitária de sementes de feijão crioulo, var. Chumbinho, após microbiolização com doses de um produto comercial (p.c.) com Trichoderma harzianum (cepa ESALQ-1306). Os tratamentos foram: T1) 100 mL p.c./100 kg de sementes; T2) 150 mL p.c.; T3) 200 mL p.c.; T4) 200 mL tratamento químico (p.c., 250 g L-1 fipronil + 25 g L-1 piraclostrobina + 225 g L-1 tiofanato metílico); e T5) controle (sem revestimento de sementes). Os testes foram: sanidade (blotter test), germinação, primeira contagem, envelhecimento acelerado, teste de frio sem solo, índice de velocidade de germinação (IVG), comprimento de parte aérea e de raiz das plântulas e emergência em casa de vegetação. T. harzianum controlou Aspergillus spp., Penicillium spp. e Fusarium oxysporum. A dose 100 mL de p.c. teve melhores resultados para germinação e vigor, sendo que essa dose é uma alternativa ao tratamento químico em sementes de feijão crioulo.(AU)

Endophytic fungi from Brachiaria grasses in Brazil and preliminary screening of Sclerotinia sclerotiorum antagonists

Fungal endophytes of Brachiaria, a nonhost of Sclerotinia sclerotiorum, may harbor species with antagonistic effects against this plant pathogen. The objective of this work was to investigate the diversity of endophytic fungi associated with different Brachiaria species and hybrids and evaluate their potential to inhibit the plant pathogen S. sclerotiorum. Stem samples from 39 Brachiaria spp. plants were collected in pasture fields and experimental areas of three states of Brazil resulting in 74 endophytes isolated. Twenty-eight species were identified by sequences of the Internal Transcribed Spacer (ITS) and 18S rDNA regions. Paraconiothyrium sp. was the most abundant endophyte, accounting for 24 % (14 isolates) of total, and it was isolated from B. ruziziensis, B. decumbens, B. humidicola, and B. brizantha. Phoma sorghina was the second most abundant taxon, followed by Sarocladium strictum, and Plenodomus sp. In vitro analyses showed that Paraconiothyrium sp., Sarocladium kiliense, Acremonium curvulum, Setophoma terrestris, Dissoconium sp., and Cladosporium flabelliforme exhibited antagonistic activity against S. sclerotiorum, with percentages of growth inhibition ranging from 25 to 60 (p < 0.05). Paraconiothyrium sp. BBXE1 (60 %), BBPB4.1 (60 %), BCMT4.1 (54 %), and S. kiliense (54 %) showed the highest values of Antagonism Percentages (AP). Therefore, fungi with inhibitory activity against S. sclerotiorum such as Paraconiothyrium sp. are naturally endophytic in Brachiaria grasses.

Endophytic fungi from Brachiaria grasses in Brazil and preliminary screening of Sclerotinia sclerotiorum antagonists

Fungal endophytes of Brachiaria, a nonhost of Sclerotinia sclerotiorum, may harbor species with antagonistic effects against this plant pathogen. The objective of this work was to investigate the diversity of endophytic fungi associated with different Brachiaria species and hybrids and evaluate their potential to inhibit the plant pathogen S. sclerotiorum. Stem samples from 39 Brachiaria spp. plants were collected in pasture fields and experimental areas of three states of Brazil resulting in 74 endophytes isolated. Twenty-eight species were identified by sequences of the Internal Transcribed Spacer (ITS) and 18S rDNA regions. Paraconiothyrium sp. was the most abundant endophyte, accounting for 24 % (14 isolates) of total, and it was isolated from B. ruziziensis, B. decumbens, B. humidicola, and B. brizantha. Phoma sorghina was the second most abundant taxon, followed by Sarocladium strictum, and Plenodomus sp. In vitro analyses showed that Paraconiothyrium sp., Sarocladium kiliense, Acremonium curvulum, Setophoma terrestris, Dissoconium sp., and Cladosporium flabelliforme exhibited antagonistic activity against S. sclerotiorum, with percentages of growth inhibition ranging from 25 to 60 (p < 0.05). Paraconiothyrium sp. BBXE1 (60 %), BBPB4.1 (60 %), BCMT4.1 (54 %), and S. kiliense (54 %) showed the highest values of Antagonism Percentages (AP). Therefore, fungi with inhibitory activity against S. sclerotiorum such as Paraconiothyrium sp. are naturally endophytic in Brachiaria grasses.(AU)

Histochemical changes induced by Trichoderma spp. and potassium phosphite in common bean (Phaseolus vulgaris) in response to the attack by Colletotrichum lindemuthianum / Alterações histoquímicas induzidas por Trichoderma spp. e fosfito de potássio no feijoeiro (Phaseolus vulgaris) em resposta ao ataque de Colletotrichum lindemuthianum

Induction of resistance in common bean (Phaseolus vulgaris) has been considered a promising alternative to control anthracnose. Among the changes generated in the induction of resistance, structural changes have been reported by several authors as an efficient form of resistance to the stress plants undergo. Histochemical analysis techniques have been used to investigate tissue changes triggered by induction of resistance. Thus, this study aims to investigate certain histochemical changes suffered by common bean plants induced with potassium phosphite and Trichoderma spp. in response to the attack by Colletotrichum lindemuthianum, aiming to determine the host response pattern in terms of structural changes, associating it to possible disease control. Treatments consisted of isolates T. harzianum (isolate TOD1) and T. virens (isolate TM4), leaf fertilizer potassium phosphite Fertilis®, and distilled water (control). Inducers were applied to common bean alone or associated, consisting of five treatments plus the control treatment. The six treatments were evaluated for the absence and presence of C. lindemuthianum in a factorial scheme (6×2). Treatments allowed evaluating the severity of anthracnose in common bean, location of H2O2, lignin deposition, and hypersensitivity response in common bean hypocotyl by histochemical staining. Potassium phosphite and combinations of T. virens and T. harzianum with potassium phosphite efficiently reduced disease severity under greenhouse conditions, reaching 68, 84, and 71%, respectively. Studies with hypocotyl showed that T. harzianum + potassium phosphite and T. virens + potassium phosphite accelerated the H2O2 accumulation process and lignin deposition at the pathogen penetration site, in addition to the hypersensitivity reaction through the resistance-inducing activity, contributing to the protection of common bean against anthracnose caused by C. lindemuthianum.

No cultivo do feijoeiro (Phaseolus vulgaris) a indução de resistência tem sido considerada uma alternativa promissora para o controle da antracnose. Dentre as alterações geradas na indução de resistência, as mudanças estruturais têm sido relatadas por diversos autores como uma forma eficiente de resistência ao estresse sofrido pela planta. Técnicas de análises histoquímicas têm sido utilizadas com o objetivo de investigar as alterações teciduais desencadeadas pela indução de resistência. Dessa forma, o presente trabalho tem por objetivo investigar determinadas alterações histoquímicas sofridas pelas plantas de feijoeiro induzidas com fosfito de potássio e Trichoderma spp. frente ao ataque de Colletotrichum lindemuthianum, visando determinar o padrão de resposta do hospedeiro em termos de modificações estruturais, associando esse padrão de resposta ao possível controle da doença. Os tratamentos consistiram de dois isolados: T. harzianum (isolado TOD1) e T. virens (isolado TM4), do fertilizante foliar Fosfito de Potássio Fertilis® e do tratamento com água destilada (controle). Os indutores foram aplicados no feijoeiro isoladamente ou combinados, constituindo cinco tratamentos mais o tratamento controle. Os seis tratamentos foram avaliados na ausência e presença de C. lindemuthianum em esquema fatorial (6x2). Mediante os tratamentos realizados, avaliou-se a severidade da antracnose no feijoeiro; localização de H2O2; deposição de lignina e resposta de hipersensibilidade em hipocótilo de feijoeiro por colorações histoquímicas. Em condições de casa de vegetação verificou-se que o fosfito de potássio e as combinações de Trichoderma virens e Trichoderma harzianum com fosfito de potássio reduziram de forma eficiente a severidade da doença, alcançando 68%, 84% e 71% respectivamente. Nos estudos com o hipocótilo, verificou-se que Trichoderma harzianum + fosfito de potássio...

Histochemical changes induced by Trichoderma spp. and potassium phosphite in common bean (Phaseolus vulgaris) in response to the attack by Colletotrichum lindemuthianum / Alterações histoquímicas induzidas por Trichoderma spp. e fosfito de potássio no feijoeiro (Phaseolus vulgaris) em resposta ao ataque de Colletotrichum lindemuthianum

Induction of resistance in common bean (Phaseolus vulgaris) has been considered a promising alternative to control anthracnose. Among the changes generated in the induction of resistance, structural changes have been reported by several authors as an efficient form of resistance to the stress plants undergo. Histochemical analysis techniques have been used to investigate tissue changes triggered by induction of resistance. Thus, this study aims to investigate certain histochemical changes suffered by common bean plants induced with potassium phosphite and Trichoderma spp. in response to the attack by Colletotrichum lindemuthianum, aiming to determine the host response pattern in terms of structural changes, associating it to possible disease control. Treatments consisted of isolates T. harzianum (isolate TOD1) and T. virens (isolate TM4), leaf fertilizer potassium phosphite Fertilis®, and distilled water (control). Inducers were applied to common bean alone or associated, consisting of five treatments plus the control treatment. The six treatments were evaluated for the absence and presence of C. lindemuthianum in a factorial scheme (6×2). Treatments allowed evaluating the severity of anthracnose in common bean, location of H2O2, lignin deposition, and hypersensitivity response in common bean hypocotyl by histochemical staining. Potassium phosphite and combinations of T. virens and T. harzianum with potassium phosphite efficiently reduced disease severity under greenhouse conditions, reaching 68, 84, and 71%, respectively. Studies with hypocotyl showed that T. harzianum + potassium phosphite and T. virens + potassium phosphite accelerated the H2O2 accumulation process and lignin deposition at the pathogen penetration site, in addition to the hypersensitivity reaction through the resistance-inducing activity, contributing to the protection of common bean against anthracnose caused by C. lindemuthianum.(AU)

No cultivo do feijoeiro (Phaseolus vulgaris) a indução de resistência tem sido considerada uma alternativa promissora para o controle da antracnose. Dentre as alterações geradas na indução de resistência, as mudanças estruturais têm sido relatadas por diversos autores como uma forma eficiente de resistência ao estresse sofrido pela planta. Técnicas de análises histoquímicas têm sido utilizadas com o objetivo de investigar as alterações teciduais desencadeadas pela indução de resistência. Dessa forma, o presente trabalho tem por objetivo investigar determinadas alterações histoquímicas sofridas pelas plantas de feijoeiro induzidas com fosfito de potássio e Trichoderma spp. frente ao ataque de Colletotrichum lindemuthianum, visando determinar o padrão de resposta do hospedeiro em termos de modificações estruturais, associando esse padrão de resposta ao possível controle da doença. Os tratamentos consistiram de dois isolados: T. harzianum (isolado TOD1) e T. virens (isolado TM4), do fertilizante foliar Fosfito de Potássio Fertilis® e do tratamento com água destilada (controle). Os indutores foram aplicados no feijoeiro isoladamente ou combinados, constituindo cinco tratamentos mais o tratamento controle. Os seis tratamentos foram avaliados na ausência e presença de C. lindemuthianum em esquema fatorial (6x2). Mediante os tratamentos realizados, avaliou-se a severidade da antracnose no feijoeiro; localização de H2O2; deposição de lignina e resposta de hipersensibilidade em hipocótilo de feijoeiro por colorações histoquímicas. Em condições de casa de vegetação verificou-se que o fosfito de potássio e as combinações de Trichoderma virens e Trichoderma harzianum com fosfito de potássio reduziram de forma eficiente a severidade da doença, alcançando 68%, 84% e 71% respectivamente. Nos estudos com o hipocótilo, verificou-se que Trichoderma harzianum + fosfito de potássio...(AU)

Action of Trichodermil 1306 in the control of Fusarium oxysporum f. sp. lycopersici in tomato crops / Ação do Trichodermil 1306 no controle de Fusarium oxysporum f. sp. lycopersici na cultura do tomateiro

Fusarium wilt, caused by Fusarium oxysporum f. sp. lycopersici, is one of the most important diseases of tomato crop in Brazil. Several alternatives to fungicides have been evaluated in search for products that control this disease and have low environmental impact and toxicity to living beings. In this context, the use of Trichoderma spp. is an alternative to agrochemicals, since they are bioregulators and antagonists of several phytopathogens. This work aimed to evaluate the antagonistic and mycoparasitory action of the Trichodermil 1306 biofungicide against F. oxysporum, and its action in the control of fusarium wilt in tomato seeds and seedlings. The biofungicide was used at concentrations of 0, 50, 100, and 150% of the dose recommended for application of 20 L with a backpack sprayer. The experiment was conducted in a completely randomized design with five replications. Data were submitted to analysis of variance and mean compared by Tukey's test at 5% probability. The 100% Trichodermil concentration was the most efficient for treating tomato seeds. Although this concentration did not show differences in relation to the lowest dose used (50%) in the tomato seed antagonism, mycoparasitism and F. oxysporum incidence tests were recommended because that the lowest concentration resulted in 18% lower root protrusion than that observed with 100% dosage. The in vitro antagonistic and mycoparasitory action of this biological fungicide indicates its potential in the control of fusarium wilt in tomato crops.(AU)

A murcha-de-fusário, causada por Fusarium oxysporum f. sp. lycopersici, é uma das mais importantes doenças da cultura do tomate no Brasil. Várias alternativas aos fungicidas têm sido avaliadas na busca de produtos que controlem a doença e tenham baixo impacto ambiental e toxicidade aos seres vivos. Nesse contexto, o uso de Trichoderma spp. é uma alternativa a agrotóxicos, pois são biorreguladores e antagonistas de vários fitopatógenos. O objetivo do trabalho foi avaliar a ação antagonista e micoparasitória do biofungicida Trichodermil 1306 em F. oxysporum, e no controle da murcha-de-fusário em sementes e mudas de tomate. O biofungicida foi utilizado nas concentrações de 0, 50, 100 e 150% da dose recomendada para aplicação com pulverizador costal de 20 L. O experimento foi conduzido em delineamento inteiramente casualizado, com cinco repetições. Os dados foram submetidos à análise de variância e as médias foram comparadas pelo teste de Tukey a 5% de probabilidade. A concentração de Trichodermil 100% foi a mais eficaz para o tratamento de sementes de tomateiro. Embora essa concentração não tenha se diferenciado da menor dosagem utilizada (50%) para os testes de antagonismo, micoparasitismo e incidência de F. oxysporum em mudas de tomate, sua recomendação se justifica pelo fato da menor concentração ter propiciado protrusão radicular 18% menor do que a observada na concentração de 100%. A ação antagonista e micoparasitória in vitro do fungicida biológico testado no presente estudo indica potencialidade de uso para o controle de murcha-de-fusário em tomateiro.(AU)

Action of Trichodermil 1306 in the control of Fusarium oxysporum f. sp. lycopersici in tomato crops / Ação do Trichodermil 1306 no controle de Fusarium oxysporum f. sp. lycopersici na cultura do tomateiro

Fusarium wilt, caused by Fusarium oxysporum f. sp. lycopersici, is one of the most important diseases of tomato crop in Brazil. Several alternatives to fungicides have been evaluated in search for products that control this disease and have low environmental impact and toxicity to living beings. In this context, the use of Trichoderma spp. is an alternative to agrochemicals, since they are bioregulators and antagonists of several phytopathogens. This work aimed to evaluate the antagonistic and mycoparasitory action of the Trichodermil 1306 biofungicide against F. oxysporum, and its action in the control of fusarium wilt in tomato seeds and seedlings. The biofungicide was used at concentrations of 0, 50, 100, and 150% of the dose recommended for application of 20 L with a backpack sprayer. The experiment was conducted in a completely randomized design with five replications. Data were submitted to analysis of variance and mean compared by Tukey's test at 5% probability. The 100% Trichodermil concentration was the most efficient for treating tomato seeds. Although this concentration did not show differences in relation to the lowest dose used (50%) in the tomato seed antagonism, mycoparasitism and F. oxysporum incidence tests were recommended because that the lowest concentration resulted in 18% lower root protrusion than that observed with 100% dosage. The in vitro antagonistic and mycoparasitory action of this biological fungicide indicates its potential in the control of fusarium wilt in tomato crops.(AU)

A murcha-de-fusário, causada por Fusarium oxysporum f. sp. lycopersici, é uma das mais importantes doenças da cultura do tomate no Brasil. Várias alternativas aos fungicidas têm sido avaliadas na busca de produtos que controlem a doença e tenham baixo impacto ambiental e toxicidade aos seres vivos. Nesse contexto, o uso de Trichoderma spp. é uma alternativa a agrotóxicos, pois são biorreguladores e antagonistas de vários fitopatógenos. O objetivo do trabalho foi avaliar a ação antagonista e micoparasitória do biofungicida Trichodermil 1306 em F. oxysporum, e no controle da murcha-de-fusário em sementes e mudas de tomate. O biofungicida foi utilizado nas concentrações de 0, 50, 100 e 150% da dose recomendada para aplicação com pulverizador costal de 20 L. O experimento foi conduzido em delineamento inteiramente casualizado, com cinco repetições. Os dados foram submetidos à análise de variância e as médias foram comparadas pelo teste de Tukey a 5% de probabilidade. A concentração de Trichodermil 100% foi a mais eficaz para o tratamento de sementes de tomateiro. Embora essa concentração não tenha se diferenciado da menor dosagem utilizada (50%) para os testes de antagonismo, micoparasitismo e incidência de F. oxysporum em mudas de tomate, sua recomendação se justifica pelo fato da menor concentração ter propiciado protrusão radicular 18% menor do que a observada na concentração de 100%. A ação antagonista e micoparasitória in vitro do fungicida biológico testado no presente estudo indica potencialidade de uso para o controle de murcha-de-fusário em tomateiro.(AU)

Vermicomposto bioenriquecido com Trichoderma spp / Vermicompost bioenriched with Trichoderma spp

A ciclagem de resíduos de origem animal pelo processo de compostagem e sua transformação em insumos para produção vegetal além de minimizarem os impactos ambientais, podem ser uma importante fonte de renda ao produtor. Além disso, a compostagem desses resíduos produz um insumo agrícola com elevado potencial na produção de hortaliças e com possibilidade de associação com organismos de controle biológico, possibilitando a produção de um substrato ecologicamente correto, rico em nutrientes e protetor da saúde das plantas. Nesse sentido, o objetivo deste trabalho foi avaliar a sobrevivência do fungo Trichoderma spp. durante o processo de vermicompostagem, as alterações físico/químicas ocasionadas no substrato e o crescimento e desenvolvimento de plantas de alface cultivadas. Foram avaliados, como substratos base, resíduos da criação de ovinos; cavalos e coelhos, com ou sem a adição de Trichoderma spp. Em todos os tratamentos foram adicionadas minhocas da espécie Eisenia fetida. Os tratamentos foram arranjados em esquema fatorial 3x2 e o delineamento experimental foi o inteiramente casualizado, com 4 repetições O fungo Trichoderma spp. sobrevive durante o processo de vermicompostagem dos diferentes resíduos. A utilização de Trichoderma spp. não teve efeito nos teores de fósforo, magnésio e matéria orgânica, reduziu os valores de cálcio, elevou os teores de potássio para o substrato a base de coelho, aumentou a densidade seca do substrato base de resíduos de coelho e reduziu do substrato base de resíduos de cavalos. O substrato que proporcionou o melhor crescimento e desenvolvimento de plantas de alface foi o de resíduos de criação de cavalos, sendo favorecido pela presença de Trichoderma spp. no segundo ano de cultivo.(AU)

The intensification of agropastoral activity leads to a high production of waste. The composting of these residues produces an agricultural input with high potential in the production of vegetables and with the possibility of association with organisms of biological control, allowing the production of an ecologically correct substrate, rich in nutrients and protector of the health of the plants. In this sense, the objective of this work was to evaluate the survival of the fungus Trichoderma spp. During the vermicompost process,as the physical / chemical development caused not substrate and the growth and development of lettuce plants grown in the different treatments used. Basal substrates were obtained from the creation of three different animals: sheep, Horses and rabbits, whether or not containing added Trichoderma spp. In all treatments, worms of Eisenia foetida were added. Evaluations of fungus survival, physical and chemical analyzes of the substrate produced and evaluation without growth and development of lettuce plants were carried out. The treatments were arranged in a 3x2 factorial scheme and the experimental design was completely randomized, with 4 replicates. Data were analyzed using Sisvar® software, and as means averages compared by Scott Knott's test at 5% error probability. Trichoderma spp. It survives the vermicompost process by improving the development of lettuce plants when associated with farmsresidue. The use of Trichoderma spp. It reduced the calcium values of all substrates, raised a dry density of the base substrate of rabbit residues, and reduced the base substrate of farmyard residues. The substrate that provided the best growth and development of lettuce plants was the residues of rearing of horses, being favored by the presence of Trichoderma spp. in the second year.(AU)

Vermicomposto bioenriquecido com Trichoderma spp / Vermicompost bioenriched with Trichoderma spp

A ciclagem de resíduos de origem animal pelo processo de compostagem e sua transformação em insumos para produção vegetal além de minimizarem os impactos ambientais, podem ser uma importante fonte de renda ao produtor. Além disso, a compostagem desses resíduos produz um insumo agrícola com elevado potencial na produção de hortaliças e com possibilidade de associação com organismos de controle biológico, possibilitando a produção de um substrato ecologicamente correto, rico em nutrientes e protetor da saúde das plantas. Nesse sentido, o objetivo deste trabalho foi avaliar a sobrevivência do fungo Trichoderma spp. durante o processo de vermicompostagem, as alterações físico/químicas ocasionadas no substrato e o crescimento e desenvolvimento de plantas de alface cultivadas. Foram avaliados, como substratos base, resíduos da criação de ovinos; cavalos e coelhos, com ou sem a adição de Trichoderma spp. Em todos os tratamentos foram adicionadas minhocas da espécie Eisenia fetida. Os tratamentos foram arranjados em esquema fatorial 3x2 e o delineamento experimental foi o inteiramente casualizado, com 4 repetições O fungo Trichoderma spp. sobrevive durante o processo de vermicompostagem dos diferentes resíduos. A utilização de Trichoderma spp. não teve efeito nos teores de fósforo, magnésio e matéria orgânica, reduziu os valores de cálcio, elevou os teores de potássio para o substrato a base de coelho, aumentou a densidade seca do substrato base de resíduos de coelho e reduziu do substrato base de resíduos de cavalos. O substrato que proporcionou o melhor crescimento e desenvolvimento de plantas de alface foi o de resíduos de criação de cavalos, sendo favorecido pela presença de Trichoderma spp. no segundo ano de cultivo.

The intensification of agropastoral activity leads to a high production of waste. The composting of these residues produces an agricultural input with high potential in the production of vegetables and with the possibility of association with organisms of biological control, allowing the production of an ecologically correct substrate, rich in nutrients and protector of the health of the plants. In this sense, the objective of this work was to evaluate the survival of the fungus Trichoderma spp. During the vermicompost process,as the physical / chemical development caused not substrate and the growth and development of lettuce plants grown in the different treatments used. Basal substrates were obtained from the creation of three different animals: sheep, Horses and rabbits, whether or not containing added Trichoderma spp. In all treatments, worms of Eisenia foetida were added. Evaluations of fungus survival, physical and chemical analyzes of the substrate produced and evaluation without growth and development of lettuce plants were carried out. The treatments were arranged in a 3x2 factorial scheme and the experimental design was completely randomized, with 4 replicates. Data were analyzed using Sisvar® software, and as means averages compared by Scott Knott's test at 5% error probability. Trichoderma spp. It survives the vermicompost process by improving the development of lettuce plants when associated with farmsresidue. The use of Trichoderma spp. It reduced the calcium values of all substrates, raised a dry density of the base substrate of rabbit residues, and reduced the base substrate of farmyard residues. The substrate that provided the best growth and development of lettuce plants was the residues of rearing of horses, being favored by the presence of Trichoderma spp. in the second year.

Predatory activity of Butlerius nematodes and nematophagous fungi against Haemonchus contortus infective larvae / Atividade predatória de nematóides Butlerius e fungos nematófagos contra larvas infectantes de Haemonchus contortus

The purpose of this study was to evaluate the predatory activity of the nematode Butlerius spp. and fungal isolates of Duddingtonia flagrans, Clonostachys rosea, Arthrobotrys musiformis and Trichoderma esau against H. contortusinfective larvae (L3) in grass pots. Forty-eight plastic gardening pots containing 140 g of sterile soil were used. Panicum spp. grass seeds (200 mg) were sown into each pot and individually watered with 10 mL of tap water. Twelve days after seeding, the pots were randomly divided into 6 groups (n=8). Two thousand H. contortus infective larvae (L3) were added to each group. Additionally, the following treatments were established: Group 1 2000 Butlerius spp. larvae; group 2 A. musiformis (1x107 conidia); group 3 T. esau (1x107 conidia); group 4 C. rosea (1x107 conidia), group 5 D. flagrans (1x107conidia) and Group 6 no biological controller (control group). The larval population of H. contortus exposed to Butlerius spp. was reduced by 61.9%. Population reductions of 90.4, 66.7, 61.9 and 85.7% were recorded in the pots containing A. musiformis, T. esau, C. rosea and D. flagrans, respectively. The results of this study indicate that the predatory nematode Butlerius spp. and the assessed fungi display an important predatory activity can be considered suitable potential biological control agents.(AU)

O objetivo deste estudo foi avaliar a atividade predatória do nematoide Butlerius spp. e isolados fúngicos de Duddingtonia flagrans, Clonostachys rosea, Arthrobotrys musiformis e Trichoderma esau contra larvas infectantes (L3) de Haemonchus contortus em vasos plantados com Panicum spp. Foram utilizados quarenta e oito potes plásticos de jardinagem contendo 140 g de solo estéril, 200 mg de sementes de Panicum spp.. Cultivar colonião, foi semeado em cada vaso e, diariamente, molhados com 10 mL de água da torneira. Doze dias após, os vasos foram divididos em 6 grupos (n = 8), e duas mil L3 de H. contortus foram adicionadas a cada vaso. Foram estabelecidos os seguintes tratamentos: Grupo 1 - 2.000 larvas de Butlerius spp.; Grupo 2 - A. musiformis (1x107 conídios); grupo 3 - T. esau (1x107 conídios); grupo 4 - C. rosea (1x107 conídios); grupo 5 - D. flagrans (1x107conidia); e Grupo 6 somente L3 de H. contortus que serviu como controle negativo. A população de L3 de H. contortus expostas a Butlerius spp. foi reduzida em 61,9%. Redução populacional de 90,4, 66,7, 61,9 e 85,7% foram observadas nos vasos contendo A. musiformis, T. esau, C. rosea e D. flagrans, respectivamente. Os resultados deste estudo indicaram que o nematoide Butlerius spp. e os fungos avaliados exibiram importante atividade predatória e podem ser considerados como agentes de controle biológico.(AU)

Cultural conditions on the production of extracellular enzymes by Trichoderma isolates from tobacco rhizosphere

Twelve isolates of Trichoderma spp. isolated from tobacco rhizosphere were evaluated for their ability to produce chitinase and -1,3-glucanase extracellular hydrolytic enzymes. Isolates ThJt1 and TvHt2, out of 12 isolates, produced maximum activities of chitinase and -1,3-glucanase, respectively. In vitro production of chitinase and -1,3-glucanase by isolates ThJt1 and TvHt2 was tested under different cultural conditions. The enzyme activities were significantly influenced by acidic pH and the optimum temperature was 30 °C. The chitin and cell walls of Sclerotium rolfsii, as carbon sources, supported the maximum and significantly higher chitinase activity by both isolates. The chitinase activity of isolate ThJt1 was suppressed significantly by fructose (80.28%), followed by glucose (77.42%), whereas the -1,3-glucanase activity of ThJt1 and both enzymes of isolate TvHt2 were significantly suppressed by fructose, followed by sucrose. Ammonium nitrate as nitrogen source supported the maximum activity of chitinase in both isolates, whereas urea was a poor nitrogen source. Production of both enzymes by the isolates was significantly influenced by the cultural conditions. Thus, the isolates ThJt1 and TvHt2 showed higher levels of chitinase and -1,3-glucanase activities and were capable of hydrolyzing the mycelium of S. rolfsii infecting tobacco. These organisms can be used therefore for assessment of their synergism in biomass production and biocontrol efficacy and for their field biocontrol ability against S. rolfsii and Pythium aphanidermatum infecting tobacco. (AU)

Biological control of banana black Sigatoka disease with Trichoderma / Controle biológico da Sigatoka-negra da bananeira com Trichoderma

Black Sigatoka disease caused by Mycosphaerella fijiensis is the most severe banana disease worldwide. The pathogen is in an invasive phase in Brazil and is already present in most States of the country. The potential of 29 isolates of Trichoderma spp. was studied for the control of black Sigatoka disease under field conditions. Four isolates were able to significantly reduce disease severity and were further tested in a second field experiment. Isolate 2.047 showed the best results in both field experiments and was selected for fungicide sensitivity tests and mass production. This isolate was identified as Trichoderma atroviride by sequencing fragments of the ITS region of the rDNA and tef-1 of the RNA polymerase. Trichoderma atroviride was as effective as the fungicide Azoxystrobin, which is recommended for controlling black Sigatoka. This biocontrol agent has potential to control the disease and may be scaled-up for field applications on rice-based solid fermentation.(AU)

A Sigatoka-negra causada por Mycosphaerella fijiensis é a doença mais destrutiva da bananeira em termos mundiais. O patógeno está em uma fase invasiva no Brasil e já se encontra distribuído na maior parte dos Estados do país. O potencial de 29 isolados de Trichoderma spp. para o controle da Sigatoka-negra foi estudado sob condições de campo. Quatro isolados foram capazes de reduzir significativamente a severidade da doença e foram selecionados para um segundo experimento de campo. O isolado 2.047 apresentou os melhores resultados e foi utilizado em testes de sensibilidade a fungicidas e produção massal. Esse isolado foi identificado como Trichoderma atroviride por meio do sequenciamento de fragmentos da regiões ITS do rDNA e tef-1 da RNA polymerase. Trichoderma atroviride foi tão efetivo no controle da Sigatoka-negra quanto o fungicida Azoxystrobin, que é recomendado para o controle da doença. O agente de controle biológico tem potencial para o controle da Sigatoka-negra e pode ser produzido em massa em arroz autoclavado para aplicações no campo.(AU)

Atividade antibacteriana de nanopartículas de prata de Trichoderma sobre Aeromonoas spp. provenientes de piscicultura

A nanociencia estuda fenomenos que ocorrem em escala nanometrica. A nanotecnologia por sua vez e a aplicacao da nanociencia na obtencao e estudo de materiais nanometricos. Dentre estes nanomateriais, estao as nanoparticulas de prata que possuem as mais diversas aplicacoes, sendo a atividade antimicrobiana a mais comumente difundida em tempos onde a resistencia antimicrobiana e considerada um problema grave. Estas nanoparticulas podem ser obtidas a partir de sintese quimica, fisica e biologica, sendo esta ultima mais vantajosa se compararmos com as demais pois e considerada ecologicamente correta por ser menos poluente e de baixo custo. Este estudo teve como objetivo avaliar o potencial de quatro linhagens de Trichoderma em biossintetizar nanoparticulas de prata. Foram avaliadas as linhagens Trichoderma brevicompactum P16D2, T. harzianum P4A, T. inhamatum P21C e T. tomentosum P14C2. O fungo T. harzianum P4A foi o mais eficiente, sendo detectada a mudanca de coloracao do filtrado micelial a partir de 24h. A mudanca de coloracao dos demais ocorreu a partir de 72h de biossintese. A caracterizacao parcial foi realizada, e foram detectadas bandas de ressonancia de plasmon de superficie com picos de 405 e 425 nm. A analise de DLS foi realizada apenas com a solucao coloidal de T. harzianum P4A e T. inhamatum P21C, onde o tamanho hidrodinamico foi de 72,22 e 73,82 nm; potencial zeta de -29,3 e -8,03 mV e indice de polidispersividade de 0,256 e 0,357, respectivamente. Foi realizado teste antibacteriano com a solucao coloidal de nanoparticulas dos quatro fungos contra quinze cepas de Aeromonas spp. obtidas lesoes de pele e rim de tambaqui, e cepas de referencia ATCC, sendo estas Aeromonas hydrophila, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa e Staphylococcus aureus. As maiores zonas de inibicao foram de 10,19 e 14,43 mm para T. brevicompactum P16D2, 10,30 e 11,54 mm para T. harzianum P4A, 11,03 e 13,20 mm para T. inhamatum P21C, 10,32 e 13,76 mm para T. tomentosum P14C2. O filtrado micelial de T. harzianum P4A e T. tomentosum P14C2 apresentaram zonas de inibicao, onde os maiores valores variaram de 14,79 a 16,07 mm e 8,80 a 9,55 mm, respectivamente. Foi observada reducao significativa da atividade antibacteriana apos longo tempo de preservacao das nanoparticulas, sugerindo que sejam necessarias otimizacoes dos parametros de biossintese para evitar a perda de atividade antibacteriana e torna-la mais eficiente.

Nanoscience studies phenomena that occur on a nanoscale. Nanotechnology in turn is the application of nanoscience in obtaining and studying nanometric materials. Among these nanomaterials, there are silver nanoparticles that have the most diverse applications, with antimicrobial activity being the most widespread in times when antimicrobial resistance is considered a serious problem. These nanoparticles can be obtained from chemical, physical and biological synthesis, the latter being more advantageous if compared to the others because it is considered ecologically correct because it is less polluting and low cost. This study aimed to evaluate the potential of four Trichoderma strains to biosynthesize silver nanoparticles. The strains Trichoderma brevicompactum P16D2, T. harzianum P4A, T. inhamatum P21C and T. tomentosum P14C2 were evaluated. The fungus T. harzianum P4A was the most efficient, being detected the color change of the mycelial filtrate after 24 hours. The color change of the others occurred after 72 hours of biosynthesis. Partial characterization was performed, and surface plasmon resonance bands with peaks of 405 and 425 nm were detected. DLS analysis was performed only with the colloidal solution of T. harzianum P4A and T. inhamatum P21C, where the hydrodynamic size was 72.22 and 73.82 nm; zeta potential of -29.3 and -8.03 mV and polydispersity index of 0.256 and 0.357, respectively. An antibacterial test was carried out with the colloidal solution of nanoparticles of the four fungi against fifteen strains of Aeromonas spp. obtained from skin lesions and kidney of tambaqui, and strains of ATCC reference, these being Aeromonas hydrophila, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. The largest zones of inhibition were 10.19 and 14.43 mm for T. brevicompactum P16D2, 10.30 and 11.54 mm for T. harzianum P4A, 11.03 and 13.20 mm for T. inhamatum P21C, 10, 32 and 13.76 mm for T. tomentosum P14C2. The mycelial filtrate of T. harzianum P4A and T. tomentosum P14C2 showed zones of inhibition, where the highest values ranged from 14.79 to 16.07 mm and 8.80 to 9.55 mm, respectively. A significant reduction in antibacterial activity was observed after a long time of preservation of the nanoparticles, suggesting that optimizations of the biosynthesis parameters are necessary to avoid the loss of antibacterial activity and make it more efficient.

Microbiological quality of water and dialysate from haemodialysis units in Southern Brazil / Qualidade microbiológica da água e dialisato em clínicas de hemodiálise do Sul do Brasil

Infectious diseases in renal patients may be associated with the dialysis water quality, which may be contaminated with microorganisms. In Brazil, the water quality is evaluated by analyzing total coliforms, heterotrophic bacteria, and bacterial endotoxin, but not Pseudomonas sp. and fungi. Water samples from haemodialysis units in Curitiba/PR were investigated on their conformity with the standard established by the Brazilian Health Ministry. Total coliforms, heterotrophic bacteria, P. aeruginosa and fungi counts were performed according to APHA, and LAL methodology for detecting bacterial endotoxin. All of the samples showed the total coliforms counts 1.1 MPN/100 mL,and 95 % of analyzed samples complied with the standards for heterotrophic bacteria counting. P. aeruginosa was recovered from 4 % of samples. In 15 % of samples, bacterial endotoxin was detected in values above the limit established by legislation. Yeasts were isolated from 26 % samples and filamentous fungi from 58 %, being 46 % characterized as melanized fungi. The fungi genera were Cladosporium spp., Penicillium spp., Beauveria spp., Exophiala spp., Fusarium spp., Aspergillus spp., Trichoderma spp, Acremonium spp. and Rinocladiella spp.. The study highlights the significance of P. aeruginosa and fungi detection in those systems, as these microorganisms are potentially pathogenic to immunocompromised patients(AU)

Doenças infecciosas em pacientes renais podem ser associadas à qualidade da água de diálise, que pode apresentar contaminação com microrganismos. Pelos padrões brasileiros, a qualidade da água é avaliada analisando-se coliformes totais, bactérias heterotróficas e endotoxinas bacterianas. Pseudomonas sp. e fungos não são investigados. Amostras de água de clínicas de hemodiálise em Curitiba/PR foram avaliadas quanto à conformidade com os padrões do Ministério da Saúde. Contagens de coliformes totais, bactérias heterotróficas, Pseudomonas aeruginosa e fungos foram realizadas seguindo-se APHA e detecção de endotoxina pela metodologia LAL. Todas as amostras tiveram contagens de coliformes totais abaixo de 1,1 MPN/100 mL e 95 % das amostras apresentaram padrões aceitáveis para bactérias heterotróficas. P. aeruginosa foi encontrada em quatro amostras. Em 15 % das amostras, endotoxinas bacterianas foram detectadas em valores acima dos permitidos pela legislação. Leveduras foram isoladas em 26 % das amostras e fungos filamentosos em 58 %, sendo 46 % melanizados e 27 % hialinos. Os gêneros fúngicos detectados foram Cladosporium spp., Penicillium spp., Beauveria spp., Exophiala spp., Fusarium spp., Aspergillus spp., Trichoderma spp, Acremonium spp. e Rinocladiella spp.. Foi evidenciada a importância da detecção de P. aeruginosa e fungos nestes sistemas, uma vez que estes podem ser potencialmente patogênicos para pacientes imunocomprometidos(AU)

Antibiosis of Trichoderma spp strains native to northeastern Mexico against the pathogenic fungus Macrophomina phaseolina

Abstract Sampling of agricultural soils from the Mexican northeastern region was performed to detect Trichoderma spp., genetically characterize it, and assess its potential use as a biologic control agent against Macrophomina phaseolina. M. phaseolina is a phytopathogen that attacks over 500 species of cultivated plants and causes heavy losses in the regional sorghum crop. Sampling was performed immediately after sorghum or corn harvest in an area that was approximately 170 km from the Mexico-USA border. Sixteen isolates were obtained in total. Using colony morphology and sequencing the internal transcribed spacers (ITS) 1 and 4 of 18S rDNA, 14 strains were identified as Trichoderma harzianum, T. koningiopsis and T. virens. Subsequently, their antagonistic activity against M. phaseolina was evaluated in vitro, and 11 isolates showed antagonism by competition and stopped M. phaseolina growth. In 4 of these isolates, the antibiosis phenomenon was observed through the formation of an intermediate band without growth between colonies. One strain, HTE808, was identified as Trichoderma koningiopsis and grew rapidly; when it came into contact with the M. phaseolina colony, it continued to grow and sporulated until it covered the entire petri dish. Microscopic examination confirmed that it has a high level of hyperparasitism and is thus considered to have high potential for use in the control of this phytopathogen.(AU)