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)

The potential of compounds isolated from Xylaria spp. as antifungal agents against anthracnose

Anthracnose is a crop disease usually caused by fungi in the genus Colletotrichum or Gloeosporium. These are considered one of the main pathogens, causing significant economic losses, such as in peppers and guarana. The current forms of control include the use of resistant cultivars, sanitary pruning and fungicides. However, even with the use of some methods of controlling these cultures, the crops are not free of anthracnose. Additionally, excessive application of fungicides increases the resistance of pathogens to agrochemicals and cause harm to human health and the environment. In order to find natural antifungal agents against guarana anthracnose, endophytic fungi were isolated from Amazon guarana. The compounds piliformic acid and cytochalasin D were isolated by chromatographic techniques from two Xylaria spp., guided by assays with Colletotrichum gloeosporioides. The isolated compounds were identified by spectrometric techniques, as NMR and mass spectrometry. This is the first report that piliformic acid and cytochalasin D have antifungal activity against C. gloeosporioides with MIC 2.92 and 2.46 µmol mL-1 respectively. Captan and difenoconazole were included as positive controls (MIC 16.63 and 0.02 µmol mL-1, respectively). Thus, Xylaria species presented a biotechnological potential and production of different active compounds which might be promising against anthracnose disease.(AU)

Induction of resistance to Colletotrichum truncatum in lima bean / Indução de resistência à Colletotrichum truncatum em feijão-fava

Anthracnose (Colletotrichum truncatum) is one of the major diseases of the lima bean culture, found in production fields, causing decrease in productivity. The objective of this study was to evaluate the effect of abiotic and biotic inducers applied in lima bean plants to reduce anthracnose severity. Lima bean accessions were used and treated with: the abiotic inducers calcium silicate (Agrosilício Plus) and silicate clay (Rocksil), using the 3 g dose.L-1; the biotic inducer citric biomass extract (Ecolife), at the dose of 3 mL.L-1; and distilled water as control. To evaluate the resistance induction, the results of severity and degree of resistance of fava bean at 7, 11, 15, 19 and 23 days after inoculation were considered according to the scale of grades and classes of reactions. The design was a randomized block in a factorial arrangement 4 × 15 (treatments × hits) with four blocks. Resistance inducers Agrosilicon Plus, Ecolife and Rocksil have potential to be used in the management of anthracnose in fava bean. The studied accesses showed degree of resistance, being able to be explored in relation to obtaining anthracnose resistant cultivars in future breeding programs of this crop.(AU)

A antracnose é uma das principais doenças da cultura do feijão-fava (Phaseolus lunatus L.), sendo encontrada em campos de produção e com grande potencial de causar redução na produtividade. O objetivo do trabalho foi determinar o efeito de indutores abiótico e biótico aplicados em plantas de feijão-fava, a fim de diminuir a severidade da antracnose. Foram utilizados 15 acessos de feijão-fava, tratados com os indutores abióticos: silicato de cálcio (Agrosilício Plus) e argila silicatada (Rocksil), utilizando a dose de 3 g.L-1 para ambos os produtos; e o indutor biótico biomassa cítrica (Ecolife), na dose de 3 mL.L-1. Como testemunha, aplicou-se apenas água destilada. Para avaliar a indução de resistência, foram considerados os resultados de severidade e grau de resistência dos acessos de feijão-fava aos 7, 11, 15, 19 e 23 dias após a inoculação, de acordo com escala de notas e classes de reações. O delineamento utilizado foi em blocos casualizados, em arranjo fatorial simples 4 × 15 (tratamentos × acessos) com quatro blocos. Os indutores de resistência Agrosilício Plus, Ecolife e Rocksil apresentaram potencial para serem utilizados no manejo da antracnose em feijão-fava. Os acessos estudados revelaram grau de resistência, podendo ser explorados quanto à obtenção de cultivares resistentes à antracnose em futuros programas de melhoramento genético dessa cultura.(AU)

Induction of resistance to Colletotrichum truncatum in lima bean / Indução de resistência à Colletotrichum truncatum em feijão-fava

Anthracnose (Colletotrichum truncatum) is one of the major diseases of the lima bean culture, found in production fields, causing decrease in productivity. The objective of this study was to evaluate the effect of abiotic and biotic inducers applied in lima bean plants to reduce anthracnose severity. Lima bean accessions were used and treated with: the abiotic inducers calcium silicate (Agrosilício Plus) and silicate clay (Rocksil), using the 3 g dose.L-1; the biotic inducer citric biomass extract (Ecolife), at the dose of 3 mL.L-1; and distilled water as control. To evaluate the resistance induction, the results of severity and degree of resistance of fava bean at 7, 11, 15, 19 and 23 days after inoculation were considered according to the scale of grades and classes of reactions. The design was a randomized block in a factorial arrangement 4 × 15 (treatments × hits) with four blocks. Resistance inducers Agrosilicon Plus, Ecolife and Rocksil have potential to be used in the management of anthracnose in fava bean. The studied accesses showed degree of resistance, being able to be explored in relation to obtaining anthracnose resistant cultivars in future breeding programs of this crop.(AU)

A antracnose é uma das principais doenças da cultura do feijão-fava (Phaseolus lunatus L.), sendo encontrada em campos de produção e com grande potencial de causar redução na produtividade. O objetivo do trabalho foi determinar o efeito de indutores abiótico e biótico aplicados em plantas de feijão-fava, a fim de diminuir a severidade da antracnose. Foram utilizados 15 acessos de feijão-fava, tratados com os indutores abióticos: silicato de cálcio (Agrosilício Plus) e argila silicatada (Rocksil), utilizando a dose de 3 g.L-1 para ambos os produtos; e o indutor biótico biomassa cítrica (Ecolife), na dose de 3 mL.L-1. Como testemunha, aplicou-se apenas água destilada. Para avaliar a indução de resistência, foram considerados os resultados de severidade e grau de resistência dos acessos de feijão-fava aos 7, 11, 15, 19 e 23 dias após a inoculação, de acordo com escala de notas e classes de reações. O delineamento utilizado foi em blocos casualizados, em arranjo fatorial simples 4 × 15 (tratamentos × acessos) com quatro blocos. Os indutores de resistência Agrosilício Plus, Ecolife e Rocksil apresentaram potencial para serem utilizados no manejo da antracnose em feijão-fava. Os acessos estudados revelaram grau de resistência, podendo ser explorados quanto à obtenção de cultivares resistentes à antracnose em futuros programas de melhoramento genético dessa cultura.(AU)

Common bean genotypes for agronomic and market-related traits in VCU trials

Value for Cultivation and Use (VCU) trials are undertaken when evaluating improved common bean (Phaseolus vulgaris L.) lines, and knowledge of agronomic and market-related traits and disease reaction is instrumental in making cultivar recommendations. This study evaluates the yield, cooking time, grain color and reaction to anthracnose (Colletotrichum lindemuthianum), Fusarium wilt (Fusarium oxysporum f. sp. phaseoli) and Curtobacterium wilt (Curtobacterium flaccumfaciens pv. flaccumfaciens) of 25 common bean genotypes derived from the main common bean breeding programs in Brazil. Seventeen VCU trials were carried out in the rainy season, dry season and winter season from 2009 to 2011 in the state of São Paulo. Analyses of grain color and cooking time were initiated 60 days after harvest, and disease reaction analyses were performed in the laboratory under controlled conditions. In terms of yield, no genotype superior to the controls was observed for any of the seasons under consideration. Grains from the dry season exhibited better color, while the rainy season led to the shortest cooking times. The following genotypes BRS Esteio, BRS Esplendor and IAC Imperador were resistant to anthracnose, Fusarium wilt and Curtobacterium wilt and, in general, genotypes with lighter-colored grains were more susceptible to anthracnose and Fusarium wilt.

Novel insights into the early stages of infection by oval conidia of Colletotrichum sublineolum

Anthracnose, caused by Colletotrichum sublineolum Henn. ex Sacc. & Trotter, is one of the most important sorghum [Sorghum bicolor (L.) Moench] diseases in Brazil. This fungus exhibits conidial dimorphism, producing either falcate or oval conidia on solid and liquid media, respectively. We compared patterns of the initial infection events by these two types of conidia on sorghum leaves using light microscopy and scanning electron microscopy. The infection events during the first 24 h were similar for both oval and falcate conidia. Globose and melanized apressoria were formed at 24 h after inoculation (hai) regardless of the conidia type. Dense mycelium and oval conidia developed from germinated falcate conidia at 32 hai. Hyphal mass displaying acervuli filled with falcate conidia and surrounded by setae, developed from germinated oval conidia at 48 hai. Oval conidia were as capable as falcate conidia of infecting sorghum leaves. The inherent ability to grow faster and the easeness with which oval conidia can be produced in vitro as compared to falcate, make the former a preferred choice for studies on the C. sublineolum-sorghum interaction. It would be instructive to further investigate the potential role of the oval conidia in epidemics.

Common bean genotypes for agronomic and market-related traits in VCU trials

Value for Cultivation and Use (VCU) trials are undertaken when evaluating improved common bean (Phaseolus vulgaris L.) lines, and knowledge of agronomic and market-related traits and disease reaction is instrumental in making cultivar recommendations. This study evaluates the yield, cooking time, grain color and reaction to anthracnose (Colletotrichum lindemuthianum), Fusarium wilt (Fusarium oxysporum f. sp. phaseoli) and Curtobacterium wilt (Curtobacterium flaccumfaciens pv. flaccumfaciens) of 25 common bean genotypes derived from the main common bean breeding programs in Brazil. Seventeen VCU trials were carried out in the rainy season, dry season and winter season from 2009 to 2011 in the state of São Paulo. Analyses of grain color and cooking time were initiated 60 days after harvest, and disease reaction analyses were performed in the laboratory under controlled conditions. In terms of yield, no genotype superior to the controls was observed for any of the seasons under consideration. Grains from the dry season exhibited better color, while the rainy season led to the shortest cooking times. The following genotypes BRS Esteio, BRS Esplendor and IAC Imperador were resistant to anthracnose, Fusarium wilt and Curtobacterium wilt and, in general, genotypes with lighter-colored grains were more susceptible to anthracnose and Fusarium wilt.(AU)

Novel insights into the early stages of infection by oval conidia of Colletotrichum sublineolum

Anthracnose, caused by Colletotrichum sublineolum Henn. ex Sacc. & Trotter, is one of the most important sorghum [Sorghum bicolor (L.) Moench] diseases in Brazil. This fungus exhibits conidial dimorphism, producing either falcate or oval conidia on solid and liquid media, respectively. We compared patterns of the initial infection events by these two types of conidia on sorghum leaves using light microscopy and scanning electron microscopy. The infection events during the first 24 h were similar for both oval and falcate conidia. Globose and melanized apressoria were formed at 24 h after inoculation (hai) regardless of the conidia type. Dense mycelium and oval conidia developed from germinated falcate conidia at 32 hai. Hyphal mass displaying acervuli filled with falcate conidia and surrounded by setae, developed from germinated oval conidia at 48 hai. Oval conidia were as capable as falcate conidia of infecting sorghum leaves. The inherent ability to grow faster and the easeness with which oval conidia can be produced in vitro as compared to falcate, make the former a preferred choice for studies on the C. sublineolum-sorghum interaction. It would be instructive to further investigate the potential role of the oval conidia in epidemics.(AU)

Viability and susceptibility of propagation material from coffee plants to Colletotrichum sp / Viabilidade e suscetibilidade de material propagativo de cafeeiro a Colletotrichum sp

This study aimed to verify the viability of propagation material from coffee plants descended from germplasm susceptible to blister spot disease as well as its susceptibility to Colletotrichum sp. relative to commercial coffee cultivars. In the first experiment, fruits were harvested from plants with and without symptoms of blister spot and sowed in trays containing a commercial sterilized substrate. The percentages of germinated seeds, viable plantlets and seedlings were evaluated. In diseased tissues, pathogens were isolated and identified though a pathogenicity test. In the second experiment, ten commercial cultivars and one cultivar originating from plants with blister spot were inoculated with the pathogens to assess the severity of anthracnose. Significant differences were not observed with respect to seed germination. However, the viability of plantlets and seedlings was reduced in the cultivar originating from plants with blister spot (Genotype Originated from Diseased Plants-GODP). These plants showed characteristic symptoms of blister spot, including necrosis in the leaves and hypocotyls, wilting and death. In the necrotic lesions, we observed characteristic sporulation of Colletotrichum sp. The cultivar most susceptible to anthracnose in cotyledonary leaves was Catuaí Vermelho (GODP), which presented the highest area under the disease progress curve (AUDPC)...(AU)

Objetivou-se neste trabalho verificar a viabilidade de material propagativo de cafeeiro proveniente de germoplasma susceptível a Mancha manteigosa, assim como a sua susceptibilidade a Colletotrichum sp. em comparação a cultivares comerciais de cafeeiro. No primeiro experimento, frutos foram colhidos de plantas com e sem sintomas da mancha manteigosa e a semeadura realizada em bandejas contendo substrato esterilizado. Avaliou-se a porcentagem de sementes germinadas e de plântulas e mudas viáveis. Realizou-se o isolamento, a identificação do patógeno dos tecidos doentes e o teste de patogenicidade. No segundo experimento, inoculou-se o patógeno em dez cultivares de cafeeiro e em uma cultivar originada de plantas com Mancha manteigosa (GOPD) para a avaliação da severidade da antracnose. Não houve diferença quanto à germinação das sementes. Porém, a viabilidade das plântulas e das mudas, foi reduzida nos GOPDs. Estes apresentaram sintomas da mancha manteigosa, necrose nas folhas e nos hipocótilos, murcha e morte. Nas lesões necrosadas observou-se esporulação característica de Colletotrichum spp. A cultivar Catuaí Vermelho (GOPD) foi altamente suscetível à antracnose nas folhas cotiledonares apresentando a maior AACPD em relação aos outros genótipos testados. Conclui-se que a viabilidade de material propagativo de cafeeiro proveniente de sementes de plantas com Mancha manteigosa...(AU)

Colletotrichum lindemuthianum detection in seeds of germoplasm bank bean of Santa Catarina State University / Detecção de Colletotrichum lindemuthianum em sementes do banco de germoplasma de feijão da Universidade do Estado de Santa Catarina

Beans seeds of Germoplasm bank from Santa Catarina State University (BAF/UDESC), Lages, SC, harvested in 2008/2009 e 2009/2010 seasons, were used in sanity tests of seeds with the objective to evaluate the incidence of fungus Colletotrichum lindemuthianum. The media culture were tested of Potato-Dextrose-Ágar (PDA) and V-8 (tomato juice) and the Blotter Test Method. Evaluated 17 and 13 accesses in 2009 and 2010, respectively, including in two years four commercial cultivates: Pérola, BRSSupremo, SCS 202 Guará and IPR- Uirapuru. For each analyzed material were cultivated 200 seeds, ordered in four repetitions of 50 seeds. The seeds were incubated during ten days in growing chamber with photoperiod of 12 hours and temperature of 21C. The C. lindemuthianum fungus was not detected in accesses BAF51 e BAF86 analyzed in 2009. The media V8 presented itself like the best method of detection and the cultivate SCS 202 Guará presented most of incidence of pathogen among the tested accesses. In 2010 the fungus was detected in all access, and there wasnt significant difference between substrates, however there was significant difference between the tested accesses, most wile BAF07 presented most incidence of pathogen. The presence of the fungus C. lindemuthianum in the accesses seeds of the Germoplasm Bank of Bean UDESC indicates the need to adopt control measures to reduce their incidenc

Sementes de feijão do banco de germoplasma da Universidade do Estado de Santa Catarina (BAF/UDESC), Lages, SC, colhidas nas safras agrícolas 2008/09 e 2009/10, foram utilizadas em teste de sanidade de sementes com o objetivo de avaliar a incidência do fungo Colletotrichum lindemuthianum. Foram testados como substratos os meios de cultura Batata-Dextrose-Ágar (BDA+A) e V-8 (suco de tomate) e o método do Papel de Filtro. Utilizaram-se 17 e 13 acessos de feijão em 2009 e 2010, respectivamente, incluindo, nos dois anos, quatro cultivares comerciais: Pérola, BRS-Supremo, SCS 202 Guará e IPRUirapuru. Para cada material analisado foram utilizadas 200 sementes, dispostas em quatro repetições de 50 sementes. As sementes foram incubadas durante dez dias em câmara de crescimento com fotoperíodo de 12 horas e temperatura de 21C. O fungo C. lindemuthianum não foi detectado nos acessos BAF51 e BAF86 analisados em 2009. O meio V8 apresentou-se como melhor método de detecção e a cultivar SCS 202 Guará apresentou maior incidência do patógeno dentre os acessos testados. Em 2010, o fungo foi detectado em todos os acessos e não houve diferença signifi cativa entre os substratos, mas houve diferença significativa entre os acessos testados, sendo que BAF07 apresentou maior incidência do patógeno. A presença do fungo C. lindemuthianum nas sementes de feijão dos acessos do Banco Germoplasma de Feijão

Vegetative compatibility and heterokaryon formation between different isolates of Colletotrichum lindemuthianum by using the nit mutant system

Colletotrichum lindemuthianum, the causative agent of bean anthracnose, is one of the most common pathogens leading to expressive damage to plants beyond presenting noticeable variability. The knowledge on vegetative compatibility groups (VCGs) is of particular interest in asexual fungi as they subdivide the population in groups that can exchange genetic information via heterokaryosis and the parasexual cycle. Among the techniques used in studies about vegetative compatibility groups, the obtainment of nit mutants is apparent. This paper is aimed at obtaining heterokaryons between different isolates of C. lindemuthianum, grouping them in VCGs and evaluating their genetic variability by using the nit mutants system. Nit mutants were obtained from 20 single spore isolates. The mutants were phenotypically classified and paired for complementation and formation of heterokaryons so as to group them in VCGs. Seventeen mutants from the different phenotypic-rates were recovered: nit1, nit2, nit3 and nitM. At the same time, 10 mutants were selected for pairing and division of the anastomosis groups. Nine heterokaryons were obtained and the isolates were divided into 9 vegetative compatibility groups. In the combinations for the formation of anastomosis, 31 compatible combinations and 24 incompatible combinations were observed. It was concluded that the methodology used to select nit mutants in C. lindemuthianum made it possible to determine the vegetative compatibility groups and that such a technique was adequate to prove genetic variability.

Variabilidade genética de Colletotrichum guaranicola usando marcadores AFLP / Variability of Colletotrichum guaranicola using AFLP markers

Foi detectada a variabilidade genética de vinte isolados de Colletotrichum guaranicola (Albuq.) provenientes de diferentes localidades produtoras de guaraná no Amazonas, utilizando-se marcadores moleculares AFLP. Foi possível separar os isolados em dois grupos. O coeficiente de variação genética entre os isolados foi de 0,0216 e a similaridade genética foi de 94,95 por cento, confirmando que os isolados pertencem à mesma espécie, no entanto, foi observada variabilidade intra-específica.

The genetic variability of twenty Colletotrichum guaranicola (Albuq.) isolates from different fields of guarana in Amazonas, was studied using molecular AFLP markers. The isolates were separated into two groups. The genetic variability coefficient was 0.0216 and the genetic similarity was 94.5 percent, confirming that the isolates belongs to the same species, however, an intra-specific variability was observed.

Variabilidade genética de Colletotrichum guaranicola usando marcadores AFLP

The genetic variability of twenty Colletotrichum guaranicola (Albuq.) isolates from different fields of guarana in Amazonas, was studied using molecular AFLP markers. The isolates were separated into two groups. The genetic variability coefficient was 0.0216 and the genetic similarity was 94.5%, confirming that the isolates belongs to the same species, however, an intra-specific variability was observed.

Foi detectada a variabilidade genética de vinte isolados de Colletotrichum guaranicola (Albuq.) provenientes de diferentes localidades produtoras de guaraná no Amazonas, utilizando-se marcadores moleculares AFLP. Foi possível separar os isolados em dois grupos. O coeficiente de variação genética entre os isolados foi de 0,0216 e a similaridade genética foi de 94,95%, confirmando que os isolados pertencem à mesma espécie, no entanto, foi observada variabilidade intra-específica.

Reaction of dwarf cashew clones to Colletotrichum gloeosporioides isolates in controlled environment

The cashew (Anacardium occidentale L.) crop is an important source of income for the population of the Brazilian Northeast, and anthracnose disease caused by Colletotrichum gloeosporioides leads to significant production loss. However, there is little information on either the host resistance or the variation in the aggressiveness of the pathogen under controlled environment. The reaction of commercial (CCP-06, CCP-09, CCP-76 and CCP-1001) and one non-commercial (CAP-14) dwarf cashew clones was assessed against 36 isolates of this fungus controlled environmental conditions. All the isolates, including those from hosts other than cashew, were able to cause lesions on leaves and stems of most clones, albeit to different degrees. Clone CCP-06 was the most susceptible, while clone CCP-1001 showed a level of resistance to a number of the isolates, including isolate 905, while isolates 910 and 912 were aggressive to all clones. Injury increased the susceptibility of the clones to all isolates, indicating that resistance also might be associated with structural barriers that hinder penetration. Ripened cashew apples (8-week-old), of commercial clones were susceptible to isolates 905 and 910. Immature pseudo-fruits (2-week-old), with exception of clone CCP-76 which was susceptible to both isolates showed resistance against these isolates, suggesting the presence of structural and chemical barriers. Developed nuts (8-week-old), however, were more resistant than immature nuts (2-week-old) to both isolates, probably due to their thicker exocarp cuticle and reduced number of stomatal pores.

A cultura de caju (Anacardium occidentale L.) é uma fonte de renda importante para a população do Nordeste brasileiro, sendo a antracnose causada por Colletotrichum gloeosporioides a doença que mais conduz a perdas de sua produção. Entretanto, há pouca informação para a resistência desse hospedeiro ou para a variação na agressividade do patógeno em ambiente controlado. A reação de clones comerciais (CCP-06, CCP-09, CCP-76 e CCP-1001) e um não comercial (CAP-14) de cajueiros anão-precoce, contra 36 isolados desse fungo, foi avaliada sob condições controladas. Todos os isolados, incluindo os provenientes de diferentes hospedeiros, foram capazes de causar lesões sobre folhas e hastes da maioria dos clones, ainda que em graus diferenciados. O clone CCP-06 foi o mais suscetível, enquanto o clone CCP-1001 foi resistente a mais isolados, incluindo o 905, enquanto os isolados 910 e 912 foram agressivos a todos os clones testados. A injúria mecânica das folhas aumentou a suscetibilidade dos clones a todos os isolados, indicando que a resistência pode também estar associada a barreiras estruturais que impedem a penetração. Os pseudofrutos amadurecidos (8 semanas) dos clones comerciais avaliados, foram suscetíveis a ambos os isolados testados (905 e 910), mas os jovens (2 semanas), com exceção daqueles do clone CCP-76, suscetíveis aos dois isolados, apresentaram resistência a ambos, sugerindo a ação de obstáculos estruturais e químicos diferenciados. As castanhas desenvolvidas (8 semanas), no entanto, foram mais resistentes a ambos os isolados do que as jovens (2 semanas), talvez devido à espessa cutícula do exocarpo e baixo número de estômatos.

Reaction of dwarf cashew clones to Colletotrichum gloeosporioides isolates in controlled environment

The cashew (Anacardium occidentale L.) crop is an important source of income for the population of the Brazilian Northeast, and anthracnose disease caused by Colletotrichum gloeosporioides leads to significant production loss. However, there is little information on either the host resistance or the variation in the aggressiveness of the pathogen under controlled environment. The reaction of commercial (CCP-06, CCP-09, CCP-76 and CCP-1001) and one non-commercial (CAP-14) dwarf cashew clones was assessed against 36 isolates of this fungus controlled environmental conditions. All the isolates, including those from hosts other than cashew, were able to cause lesions on leaves and stems of most clones, albeit to different degrees. Clone CCP-06 was the most susceptible, while clone CCP-1001 showed a level of resistance to a number of the isolates, including isolate 905, while isolates 910 and 912 were aggressive to all clones. Injury increased the susceptibility of the clones to all isolates, indicating that resistance also might be associated with structural barriers that hinder penetration. Ripened cashew apples (8-week-old), of commercial clones were susceptible to isolates 905 and 910. Immature pseudo-fruits (2-week-old), with exception of clone CCP-76 which was susceptible to both isolates showed resistance against these isolates, suggesting the presence of structural and chemical barriers. Developed nuts (8-week-old), however, were more resistant than immature nuts (2-week-old) to both isolates, probably due to their thicker exocarp cuticle and reduced number of stomatal pores.

A cultura de caju (Anacardium occidentale L.) é uma fonte de renda importante para a população do Nordeste brasileiro, sendo a antracnose causada por Colletotrichum gloeosporioides a doença que mais conduz a perdas de sua produção. Entretanto, há pouca informação para a resistência desse hospedeiro ou para a variação na agressividade do patógeno em ambiente controlado. A reação de clones comerciais (CCP-06, CCP-09, CCP-76 e CCP-1001) e um não comercial (CAP-14) de cajueiros anão-precoce, contra 36 isolados desse fungo, foi avaliada sob condições controladas. Todos os isolados, incluindo os provenientes de diferentes hospedeiros, foram capazes de causar lesões sobre folhas e hastes da maioria dos clones, ainda que em graus diferenciados. O clone CCP-06 foi o mais suscetível, enquanto o clone CCP-1001 foi resistente a mais isolados, incluindo o 905, enquanto os isolados 910 e 912 foram agressivos a todos os clones testados. A injúria mecânica das folhas aumentou a suscetibilidade dos clones a todos os isolados, indicando que a resistência pode também estar associada a barreiras estruturais que impedem a penetração. Os pseudofrutos amadurecidos (8 semanas) dos clones comerciais avaliados, foram suscetíveis a ambos os isolados testados (905 e 910), mas os jovens (2 semanas), com exceção daqueles do clone CCP-76, suscetíveis aos dois isolados, apresentaram resistência a ambos, sugerindo a ação de obstáculos estruturais e químicos diferenciados. As castanhas desenvolvidas (8 semanas), no entanto, foram mais resistentes a ambos os isolados do que as jovens (2 semanas), talvez devido à espessa cutícula do exocarpo e baixo número de estômatos.

Extratos de alho e alecrim na indução de faseolina em feijoeiro e fungitoxicidade sobre Colletotrichum lindemuthianum

Plant extracts may assist in controlling plants diseases due to its antimicrobial activity and activation of defense mechanisms. This study aimed to evaluate the effect of aqueous extracts of garlic and rosemary, autoclaved or non autoclaved, on the mycelial growth of Colletotrichum lindemuthianum, production of phaseollin by beans and severity of anthracnose in the field. The fungus was incubated in medium containing the extracts and its growth measured for 18 days. For phaseollin evaluation the extracts were applied on bean hypocotyls, the phytoalexin extracted in ethanol and read in spectrophotometer. The severity of anthracnose was evaluated in bean plants sprayed with the extracts and inoculated with the fungus. For the garlic extract, the greater reduction (57,6%) in micelial growth was at 3% in the non autoclaved extract, as for the rosemary extract, the greater reduction (18,6%) was in the autoclaved extract. Autoclaving had no effect on the induction of phaseollin. At field conditions, the extracts did not reduce significantly the severity of anthracnose. The non autoclaved garlic extract showed to be more efficient in reducing the mycelial growth of C. lindemuthianum, while rosemary, autoclaved or not, proved to be more effective in the induction of phaseollin.

Extratos vegetais podem auxiliar no controle de doenças de plantas, por sua atividade antimicrobiana ou pela ativação de mecanismos de defesa. Neste trabalho, objetivou-se avaliar o efeito dos extratos aquosos de alho e alecrim autoclavados e não autoclavados sobre o crescimento micelial de Colletotrichum lindemuthianum, a produção de faseolina em feijoeiro e a severidade de antracnose em campo. O fungo foi incubado em meio de cultura contendo os extratos, e o crescimento foi mensurado por 18 dias. Para avaliação de faseolina, os extratos foram aplicados sobre hipocótilos de feijão, a extração foi feita em etanol e a leitura foi realizada em espectrofotômetro. A severidade da antracnose foi avaliada em plantas de feijão pulverizadas com os extratos e inoculadas com o fungo. Para o extrato de alho, a maior redução (57,6%) no crescimento micelial foi com a dose de 3,0% do extrato não autoclavado. Já para o extrato de alecrim, a maior redução (18,6%) foi com o extrato autoclavado. A autoclavagem não teve efeito sobre a indução de faseolina. À campo, os extratos não reduziram significativamente a severidade de antracnose. O extrato de alho não autoclavado mostrou-se mais eficiente na redução do crescimento de C. lindemuthianum, enquanto que o de alecrim, autoclavado ou não, foi mais efetivo na indução de faseolina.

Extratos de alho e alecrim na indução de faseolina em feijoeiro e fungitoxicidade sobre Colletotrichum lindemuthianum

Plant extracts may assist in controlling plants diseases due to its antimicrobial activity and activation of defense mechanisms. This study aimed to evaluate the effect of aqueous extracts of garlic and rosemary, autoclaved or non autoclaved, on the mycelial growth of Colletotrichum lindemuthianum, production of phaseollin by beans and severity of anthracnose in the field. The fungus was incubated in medium containing the extracts and its growth measured for 18 days. For phaseollin evaluation the extracts were applied on bean hypocotyls, the phytoalexin extracted in ethanol and read in spectrophotometer. The severity of anthracnose was evaluated in bean plants sprayed with the extracts and inoculated with the fungus. For the garlic extract, the greater reduction (57,6%) in micelial growth was at 3% in the non autoclaved extract, as for the rosemary extract, the greater reduction (18,6%) was in the autoclaved extract. Autoclaving had no effect on the induction of phaseollin. At field conditions, the extracts did not reduce significantly the severity of anthracnose. The non autoclaved garlic extract showed to be more efficient in reducing the mycelial growth of C. lindemuthianum, while rosemary, autoclaved or not, proved to be more effective in the induction of phaseollin.

Extratos vegetais podem auxiliar no controle de doenças de plantas, por sua atividade antimicrobiana ou pela ativação de mecanismos de defesa. Neste trabalho, objetivou-se avaliar o efeito dos extratos aquosos de alho e alecrim autoclavados e não autoclavados sobre o crescimento micelial de Colletotrichum lindemuthianum, a produção de faseolina em feijoeiro e a severidade de antracnose em campo. O fungo foi incubado em meio de cultura contendo os extratos, e o crescimento foi mensurado por 18 dias. Para avaliação de faseolina, os extratos foram aplicados sobre hipocótilos de feijão, a extração foi feita em etanol e a leitura foi realizada em espectrofotômetro. A severidade da antracnose foi avaliada em plantas de feijão pulverizadas com os extratos e inoculadas com o fungo. Para o extrato de alho, a maior redução (57,6%) no crescimento micelial foi com a dose de 3,0% do extrato não autoclavado. Já para o extrato de alecrim, a maior redução (18,6%) foi com o extrato autoclavado. A autoclavagem não teve efeito sobre a indução de faseolina. À campo, os extratos não reduziram significativamente a severidade de antracnose. O extrato de alho não autoclavado mostrou-se mais eficiente na redução do crescimento de C. lindemuthianum, enquanto que o de alecrim, autoclavado ou não, foi mais efetivo na indução de faseolina.

Extratos de alho e alecrim na indução de faseolina em feijoeiro e fungitoxicidade sobre Colletotrichum lindemuthianum

Plant extracts may assist in controlling plants diseases due to its antimicrobial activity and activation of defense mechanisms. This study aimed to evaluate the effect of aqueous extracts of garlic and rosemary, autoclaved or non autoclaved, on the mycelial growth of Colletotrichum lindemuthianum, production of phaseollin by beans and severity of anthracnose in the field. The fungus was incubated in medium containing the extracts and its growth measured for 18 days. For phaseollin evaluation the extracts were applied on bean hypocotyls, the phytoalexin extracted in ethanol and read in spectrophotometer. The severity of anthracnose was evaluated in bean plants sprayed with the extracts and inoculated with the fungus. For the garlic extract, the greater reduction (57,6%) in micelial growth was at 3% in the non autoclaved extract, as for the rosemary extract, the greater reduction (18,6%) was in the autoclaved extract. Autoclaving had no effect on the induction of phaseollin. At field conditions, the extracts did not reduce significantly the severity of anthracnose. The non autoclaved garlic extract showed to be more efficient in reducing the mycelial growth of C. lindemuthianum, while rosemary, autoclaved or not, proved to be more effective in the induction of phaseollin.

Extratos vegetais podem auxiliar no controle de doenças de plantas, por sua atividade antimicrobiana ou pela ativação de mecanismos de defesa. Neste trabalho, objetivou-se avaliar o efeito dos extratos aquosos de alho e alecrim autoclavados e não autoclavados sobre o crescimento micelial de Colletotrichum lindemuthianum, a produção de faseolina em feijoeiro e a severidade de antracnose em campo. O fungo foi incubado em meio de cultura contendo os extratos, e o crescimento foi mensurado por 18 dias. Para avaliação de faseolina, os extratos foram aplicados sobre hipocótilos de feijão, a extração foi feita em etanol e a leitura foi realizada em espectrofotômetro. A severidade da antracnose foi avaliada em plantas de feijão pulverizadas com os extratos e inoculadas com o fungo. Para o extrato de alho, a maior redução (57,6%) no crescimento micelial foi com a dose de 3,0% do extrato não autoclavado. Já para o extrato de alecrim, a maior redução (18,6%) foi com o extrato autoclavado. A autoclavagem não teve efeito sobre a indução de faseolina. À campo, os extratos não reduziram significativamente a severidade de antracnose. O extrato de alho não autoclavado mostrou-se mais eficiente na redução do crescimento de C. lindemuthianum, enquanto que o de alecrim, autoclavado ou não, foi mais efetivo na indução de faseolina.

Control of Colletotrichum gloeosporioides (penz.) Sacc. In yellow passion fruit using Cymbopogon citratus essential oil

The use of antibiotics in agriculture is limited when compared to their applications in human and veterinary medicine. On the other hand, the use of antimicrobials in agriculture contributes to the drug resistance of human pathogens and has stimulated the search for new antibiotics from natural products. Essential oils have been shown to exert several biological activities including antibacterial and antifungal actions. The aim of this study was to determine the activity of 28 essential oils from medicinal plants cultivated at CPMA (Medicinal and Aromatic Plants Collection), CPQBA/UNICAMP, against Colletotrichum gloeosporioides (Penz.) Sacc., the anthracnose agent in yellow passion fruit (Passiflora edulis Sims f. flavicarpa Deg), as well as evaluating their effect in the control of post-harvest decay. The oils were obtained by water-distillation using a Clevenger-type system and their minimal inhibitory concentrations (MIC) determined by the micro-dilution method. According to the results, 15 of the 28 essential oils presented activity against Colletotrichum gloeosporioides, and the following four oils presented MIC values between 0.25 and 0.3 mg/mL: Coriandrum sativum, Cymbopogon citratus, Cymbopogon flexuosus and Lippia alba. The evaluation of Cymbopogon citratus essential oil in the control of post-harvest decay in yellow passion fruit showed that the disease index of the samples treated with the essential oil did not differ (P 0.05) from that of the samples treated with fungicide. The present study shows the potential of Cymbopogon citratus essential oil in the control of the anthracnose agent in yellow passion fruit.