Receptor-Like Kinase (RLK) as a candidate gene conferring resistance to Hemileia vastatrix in coffee

The biotrophic fungus Hemileia vastatrix causes coffee leaf rust (CLR), one of the most devastating diseases in Coffea arabica. Coffee, like other plants, has developed effective mechanisms to recognize and respond to infections caused by pathogens. Plant resistance gene analogs (RGAs) have been identified in certain plants as candidates for resistance (R) genes or membrane receptors that activate the R genes. The RGAs identified in different plants possess conserved domains that play specific roles in the fight against pathogens. Despite the importance of RGAs, in coffee plants these genes and other molecular mechanisms of disease resistance are still unknown. This study aimed to sequence and characterize candidate genes from coffee plants with the potential for involvement in resistance to H. vastatrix . Sequencing was performed based on a library of bacterial artificial chromosomes (BAC) of the coffee clone Híbrido de Timor (HdT) CIFC 832/2 and screened using a functional marker. Two RGAs, HdT_LRR_RLK1 and HdT_LRR_RLK2, containing the motif of leucine-rich repeat-like kinase (LRR-RLK) were identified. Based on the presence or absence of the HdT_LRR_RLK2 RGA in a number of differential coffee clones containing different combinations of the rust resistance gene, these RGAs did not correspond to any resistance gene already characterized (SH1-9). These genes were also analyzed using qPCR and demonstrated a major expression peak at 24 h after inoculation in both the compatible and incompatible interactions between coffee and H. vastatrix . These results are valuable information for breeding programs aimed at developing CLR-resistant cultivars, in addition to enabling a better understanding of the interactions between coffee and H. vastatrix .(AU)

Receptor-Like Kinase (RLK) as a candidate gene conferring resistance to Hemileia vastatrix in coffee

The biotrophic fungus Hemileia vastatrix causes coffee leaf rust (CLR), one of the most devastating diseases in Coffea arabica. Coffee, like other plants, has developed effective mechanisms to recognize and respond to infections caused by pathogens. Plant resistance gene analogs (RGAs) have been identified in certain plants as candidates for resistance (R) genes or membrane receptors that activate the R genes. The RGAs identified in different plants possess conserved domains that play specific roles in the fight against pathogens. Despite the importance of RGAs, in coffee plants these genes and other molecular mechanisms of disease resistance are still unknown. This study aimed to sequence and characterize candidate genes from coffee plants with the potential for involvement in resistance to H. vastatrix . Sequencing was performed based on a library of bacterial artificial chromosomes (BAC) of the coffee clone Híbrido de Timor (HdT) CIFC 832/2 and screened using a functional marker. Two RGAs, HdT_LRR_RLK1 and HdT_LRR_RLK2, containing the motif of leucine-rich repeat-like kinase (LRR-RLK) were identified. Based on the presence or absence of the HdT_LRR_RLK2 RGA in a number of differential coffee clones containing different combinations of the rust resistance gene, these RGAs did not correspond to any resistance gene already characterized (SH1-9). These genes were also analyzed using qPCR and demonstrated a major expression peak at 24 h after inoculation in both the compatible and incompatible interactions between coffee and H. vastatrix . These results are valuable information for breeding programs aimed at developing CLR-resistant cultivars, in addition to enabling a better understanding of the interactions between coffee and H. vastatrix .

Exogenous application of salicylic acid to control coffee rust

The exogenous application of salicylic acid can induce plant resistance against pathogens. However, little is known about the potential uses of this bioregulator for controlling coffee diseases. In this study, we assessed the effect of applying salicylic acid (SA – 150 mg L-1) on the management of coffee rust (Hemileia vastatrix) in a 7-year-old coffee plantation with low crop load (651.6 kg ha-1 in 2017). For comparison, plants were sprayed with protectant fungicide (copper hydroxide – CH) and standard fungicides (SF) used by local farmers (boscalid, pyraclostrobin + epoxiconazole, and copper hydroxide). Non-treated plants were included as a negative control. Five monthly applications were performed from November 2016 to March 2017. Rust incidence and severity, defoliation, and growth of plagiotropic branches were evaluated monthly. The activity of catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD) and total proteins was assessed one day after the first, third, and fifth product applications. Compared to untreated plants, SA reduced the severity and incidence of rust from 36.3 to 54.7%, while CH and SF reduced disease from 31.8 to 54.6% and from 83.8 to 88%, respectively. SA reduced defoliation by 54.1%. SA increased the concentration of CAT, APX, and SOD after the first application. However, this effect was not observed after subsequent applications. Foliar application of SA reduces the severity and incidence of coffee rust and defoliation in plants with a low crop load.

Exogenous application of salicylic acid to control coffee rust

The exogenous application of salicylic acid can induce plant resistance against pathogens. However, little is known about the potential uses of this bioregulator for controlling coffee diseases. In this study, we assessed the effect of applying salicylic acid (SA 150 mg L-1) on the management of coffee rust (Hemileia vastatrix) in a 7-year-old coffee plantation with low crop load (651.6 kg ha-1 in 2017). For comparison, plants were sprayed with protectant fungicide (copper hydroxide CH) and standard fungicides (SF) used by local farmers (boscalid, pyraclostrobin + epoxiconazole, and copper hydroxide). Non-treated plants were included as a negative control. Five monthly applications were performed from November 2016 to March 2017. Rust incidence and severity, defoliation, and growth of plagiotropic branches were evaluated monthly. The activity of catalase (CAT), ascorbate peroxidase (APX), superoxide dismutase (SOD) and total proteins was assessed one day after the first, third, and fifth product applications. Compared to untreated plants, SA reduced the severity and incidence of rust from 36.3 to 54.7%, while CH and SF reduced disease from 31.8 to 54.6% and from 83.8 to 88%, respectively. SA reduced defoliation by 54.1%. SA increased the concentration of CAT, APX, and SOD after the first application. However, this effect was not observed after subsequent applications. Foliar application of SA reduces the severity and incidence of coffee rust and defoliation in plants with a low crop load.(AU)

Genomic prediction of leaf rust resistance to Arabica coffee using machine learning algorithms

Genomic selection (GS) emphasizes the simultaneous prediction of the genetic effects of thousands of scattered markers over the genome. Several statistical methodologies have been used in GS for the prediction of genetic merit. In general, such methodologies require certain assumptions about the data, such as the normality of the distribution of phenotypic values. To circumvent the non-normality of phenotypic values, the literature suggests the use of Bayesian Generalized Linear Regression (GBLASSO). Another alternative is the models based on machine learning, represented by methodologies such as Artificial Neural Networks (ANN), Decision Trees (DT) and related possible refinements such as Bagging, Random Forest and Boosting. This study aimed to use DT and its refinements for predicting resistance to orange rust in Arabica coffee. Additionally, DT and its refinements were used to identify the importance of markers related to the characteristic of interest. The results were compared with those from GBLASSO and ANN. Data on coffee rust resistance of 245 Arabica coffee plants genotyped for 137 markers were used. The DT refinements presented equal or inferior values of Apparent Error Rate compared to those obtained by DT, GBLASSO, and ANN. Moreover, DT refinements were able to identify important markers for the characteristic of interest. Out of 14 of the most important markers analyzed in each methodology, 9.3 markers on average were in regions of quantitative trait loci (QTLs) related to resistance to disease listed in the literature.

Genomic prediction of leaf rust resistance to Arabica coffee using machine learning algorithms

Genomic selection (GS) emphasizes the simultaneous prediction of the genetic effects of thousands of scattered markers over the genome. Several statistical methodologies have been used in GS for the prediction of genetic merit. In general, such methodologies require certain assumptions about the data, such as the normality of the distribution of phenotypic values. To circumvent the non-normality of phenotypic values, the literature suggests the use of Bayesian Generalized Linear Regression (GBLASSO). Another alternative is the models based on machine learning, represented by methodologies such as Artificial Neural Networks (ANN), Decision Trees (DT) and related possible refinements such as Bagging, Random Forest and Boosting. This study aimed to use DT and its refinements for predicting resistance to orange rust in Arabica coffee. Additionally, DT and its refinements were used to identify the importance of markers related to the characteristic of interest. The results were compared with those from GBLASSO and ANN. Data on coffee rust resistance of 245 Arabica coffee plants genotyped for 137 markers were used. The DT refinements presented equal or inferior values of Apparent Error Rate compared to those obtained by DT, GBLASSO, and ANN. Moreover, DT refinements were able to identify important markers for the characteristic of interest. Out of 14 of the most important markers analyzed in each methodology, 9.3 markers on average were in regions of quantitative trait loci (QTLs) related to resistance to disease listed in the literature.(AU)

Agronomic characterization and responses to coffeeleaf rust in coffee progenies resistant to the gall nematode Meloidogyne exigua / Caracterização agronômica e reação à ferrugem de progênies de cafeeiro resistentes a Meloidogyne exigua

The aim of this study was to determine agronomic characteristics and responses to the coffee leaf rust fungus (Hemileia vastatrix Berk. et Br.) in coffee progenies resistant to the gall nematode Meloidogyne exigua. The experiment was conducted in December 2000 at Ouro Verde Farm (FazendaOuro Verde), located in the municipality of Campos Altos Minas Gerais (MG). Ten F3:4 progenies were evaluated. They were derived from crosses between CIFC 2570 Timor Hybrid selections and Catuaí cultivars known to be resistant to M. exigua. The Catuaí Vermelho IAC 99 cultivar served as a control. A randomized block design with three replicates was used. In total, there were thirty-three plots consisting of eight plants each. The following characteristics were assessed between the harvests of 2011/2012 and 2014/2015: (a) yield expressed as processed coffee bags ha-1; (b) rust incidence and severity; (c) vegetative vigor; (d) percentage of coffee fruits at the “cherry” stage; (e) percentage of floaters; (f) crown diameter; (g) percentage of coffee beans of size sieve 17 and higher; and (h) sensory analysis of the coffee beverage. The results indicated the following: (a) the H514-7-14-2, H514-7-4-5, H493- 1-2-2, H514-7-16-3, H514-7-8-11, H518-2-10-1, and H514-5-2-4 progenies were the most productive; (b) all progenies showed promising resistance to coffee leaf rust; (c) all genotypes had the potential for specialty coffee production; (d) the H493-1-2-2 progeny showed resistance both to rust and the nematode, and has good potential for specialty coffee production; and (e) the yields of the H514-7-8-11, H518-2-10-1, H514-5-2-4, H514-7-16-3, H514-7-14-2, H514-7-4-5, and H493-1-2-2 progenies were significantly higher than that of the Catuaí IAC 99 control.(AU)

O objetivo deste trabalho foi disponibilizar informações de características agronômicas e reação à ferrugem de progênies de cafeeiro resistentes a M. exigua. O experimento foi instalado em dezembro de 2000, na Fazenda Ouro Verde, situada no município de Campos Altos MG. Foram avaliadas 10 progênies F3:4 oriundas do cruzamento entre seleções de Híbrido de Timor provenientes do CIFC 2570 e cultivares do grupo Catuaí, previamente selecionadas como resistentes a M. exigua, e a cultivar Catuaí Vermelho IAC 99 como testemunha. Utilizou-se delineamento de blocos ao acaso, com três repetições, totalizando 33 parcelas constituídas de oito plantas cada. Entre as safras 2011/2012 a 2014/2015 foram avaliadas as seguintes características: produtividade em sacas de café beneficiado ha-1, incidência e severidade da ferrugem, vigor vegetativo, porcentagem de frutos no estádio “cereja”, porcentagem de frutos chochos, diâmetro de copa, porcentagem de grãos peneira 17 e acima e análise sensorial de bebida. Diante dos resultados pode-se concluir que: as progênies H514-7-14-2, H514-7-4-5, H493-1- 2-2, H514-7-16-3, H514-7-8-11, H518-2-10-1 e H514-5-2-4 são as mais produtivas; todas as progênies apresentam comportamento promissor para resistência à ferrugem do cafeeiro; todos os genótipos apresentam potencial para a produção de cafés especiais; a progênie H493-1-2-2 se mostra promissora apresentando resistência à ferrugem e ao nematóide além de apresentar bom potencial produtivo; e as progênies H514-7-8-11, H518-2-10-1, H514-5-2-4, H514-7-16-3, H514-7-14-2, H514-7-4-5 e H493-1- 2-2 tiveram produtividade estatisticamente superior à testemunha Catuaí IAC 99.(AU)

Progresso temporal da ferrugem alaranjada em cultivares de cafeeiro no oeste de São Paulo / Temporal progress of orange rust in coffee cultivars in western Sao Paulo

A ferrugem é a doença mais comum das lavouras de café. O trabalho estudou nos cultivares de Coffea arabica L. Acaiá IAC 474-19, Catuaí Amarelo IAC 47, Icatu Amarelo IAC 2944, Icatu Vermelho IAC 4045, Obatã IAC 1669-20 e Apoatã IAC 2258 (Coffea canephora Pierre ex Fhroen) a incidência da ferrugem. O ensaio foi realizado em Adamantina, SP, onde os cafeeiros foram plantados no espaçamento de 4,0 x 2,0 m, com duas plantas por cova e dispostos em 6 linhas com 15 a 20 covas cada. No período entre junho de 2008 a dezembro de 2009, quinzenalmente, coletou-se ao acaso 30 folhas obtidas nos terços superior, médio e inferior dos cafeeiros e calculou-se a porcentagem das folhas com sintomas característicos da ferrugem. Calculou-se a área abaixo da curva de progresso da ferrugem para cada um dos cultivares. Constatou-se a doença na Icatu Amarelo IAC 2944 e Icatu Vermelho IAC 4045, cultivares descritos como resistentes/tolerantes à ferrugem. Concluiuse que a incidência diferiu entre os cultivares e diminuiu com o aumento da temperatura, mas não com a precipitação pluvial. A incidência da doença menor que 5% nos cafeeiros ocorreu com temperaturas máximas médias mensais maiores que 30º C

Rust is the most common disease in the coffee plantations. This work aimed to evaluate the incidence of coffee rust in the following cultivars of Coffea arabica L.: Acaiá IAC 474-19, Catuaí Amarelo IAC 47, Icatu Amarelo IAC 2944, Icatu Vermelho IAC 4045, Obatã IAC 1669-20 and Apoatã IAC 2258 (Coffea canephora Pierre ex Fhroen). The experiment was conducted in Adamantina, northwest region of the state of São Paulo, Brazil. The coffee trees were planted at a spacing of 4.0 x 2.0 m with two plants per hole. Each plot consisted of six lines with 15 to 20 holes each. From June 2008 to December 2009, 30 leaves were randomly collected from the upper, middle and bottom portions of the trees. The leaf rust was found in all cultivars, including on Catuai Amarelo IAC 2944 and Vermelho IAC 4045, although both cultivars are considered resistant to the disease in field conditions. The infections differed significantly among cultivars. The rust symptoms declined with increasing temperature, and the rainfall did not affect the incidence of disease. The less-than-5% infection rate coincided with the occurrence of maximum monthly mean temperatures greater than 30º C.

Progresso temporal da ferrugem alaranjada em cultivares de cafeeiro no oeste de São Paulo / Temporal progress of orange rust in coffee cultivars in western Sao Paulo

A ferrugem é a doença mais comum das lavouras de café. O trabalho estudou nos cultivares de Coffea arabica L. Acaiá IAC 474-19, Catuaí Amarelo IAC 47, Icatu Amarelo IAC 2944, Icatu Vermelho IAC 4045, Obatã IAC 1669-20 e Apoatã IAC 2258 (Coffea canephora Pierre ex Fhroen) a incidência da ferrugem. O ensaio foi realizado em Adamantina, SP, onde os cafeeiros foram plantados no espaçamento de 4,0 x 2,0 m, com duas plantas por cova e dispostos em 6 linhas com 15 a 20 covas cada. No período entre junho de 2008 a dezembro de 2009, quinzenalmente, coletou-se ao acaso 30 folhas obtidas nos terços superior, médio e inferior dos cafeeiros e calculou-se a porcentagem das folhas com sintomas característicos da ferrugem. Calculou-se a área abaixo da curva de progresso da ferrugem para cada um dos cultivares. Constatou-se a doença na Icatu Amarelo IAC 2944 e Icatu Vermelho IAC 4045, cultivares descritos como resistentes/tolerantes à ferrugem. Concluiuse que a incidência diferiu entre os cultivares e diminuiu com o aumento da temperatura, mas não com a precipitação pluvial. A incidência da doença menor que 5% nos cafeeiros ocorreu com temperaturas máximas médias mensais maiores que 30º C (AU)

Rust is the most common disease in the coffee plantations. This work aimed to evaluate the incidence of coffee rust in the following cultivars of Coffea arabica L.: Acaiá IAC 474-19, Catuaí Amarelo IAC 47, Icatu Amarelo IAC 2944, Icatu Vermelho IAC 4045, Obatã IAC 1669-20 and Apoatã IAC 2258 (Coffea canephora Pierre ex Fhroen). The experiment was conducted in Adamantina, northwest region of the state of São Paulo, Brazil. The coffee trees were planted at a spacing of 4.0 x 2.0 m with two plants per hole. Each plot consisted of six lines with 15 to 20 holes each. From June 2008 to December 2009, 30 leaves were randomly collected from the upper, middle and bottom portions of the trees. The leaf rust was found in all cultivars, including on Catuai Amarelo IAC 2944 and Vermelho IAC 4045, although both cultivars are considered resistant to the disease in field conditions. The infections differed significantly among cultivars. The rust symptoms declined with increasing temperature, and the rainfall did not affect the incidence of disease. The less-than-5% infection rate coincided with the occurrence of maximum monthly mean temperatures greater than 30º C. (AU)

EFEITO DE FUNGICIDAS TRIAZÓIS SOBRE O CONTROLE DA CERCOSPORIOSE EM MUDAS DE CAFEEIRO

ABSTRACT Triazole fungicides and their mixtures with insecticides are usually employed for the control of coffee rust and leaf miner in coffee crops. In this study these chemicals were evaluated for the control of brown eye spot, caused by Cercospora coffeicola, another important disease of this crop. Three experiments were carried out in a greenhouse with coffee seedlings of the cultivar Mundo Novo IAC 501. The fungicides epoxiconazole, epoxiconazole + pyraclostrobin, tetraconazole, ciproconazole, copper oxychloride, azoxystrobin and carbendazim were applied to the leaves of coffee seedlings, and ciproconazole + tiametoxam, triadimenol + dissulfotom, and triadimenol were applied to the seedlings substrate. Controls were also included in all experiments. The seedlings were inoculated with suspensions prepared with a mixture of five C. coffeicola isolates (3-4 conidia/mL). The incidence and severity of the disease were evaluated 20 to 56 days after the inoculations. With the exception of copper oxychloride, all products were efficient for the control of brown eye spot. The triazoles, with the exception of tetraconazole, showed reversible phytotoxic effects. Ciproconazole + tiametoxam, epoxiconazole + pyraclostrobin and carbendazim had the highest residual effects and maintained small levels of the disease until 56 days after their application. The triazoles used for the control of coffee rust are also effective for the control of brown eye spot.

RESUMO Fungicidas do grupo dos triazóis e suas misturas com inseticidas são convencionalmente empregados para o controle da ferrugem e do bicho mineiro na cultura do cafeeiro. Neste estudo avaliou-se o efeito desses produtos sobre o controle da cercosporiose, causada por Cercospora coffeicola, outra importante doença do cafeeiro. Três experimentos foram realizados em casa de vegetação com mudas de cafeeiro da cultivar Mundo Novo IAC 501, sendo os produtos aplicados na parte aérea e no substrato. Os produtos aplicados na parte aérea foram: epoxiconazol, epoxiconazol + piraclostrobina, tetraconazol, ciproconazol, oxicloreto de cobre, azoxistrobina e carbendazim e no substrato: ciproconazol + tiametoxam, triadimenol + dissulfotom e triadimenol. Testemunhas sem tratamento químico também foram incluídas nos três experimentos. As mudas foram inoculadas com suspensões preparadas com cinco isolados de C. coffeicola (3-4 conídios/mL). A incidência e a severidade da doença foram avaliadas de 20 até 56 dias após as inoculações. Com exceção do oxicloreto de cobre, todos os demais tratamentos foram eficientes no controle da cercosporiose. Os triazóis, com exceção do tetraconazol, apresentaram sintomas reversíveis de fitotoxicidade. Os produtos: ciproconazol + tiametoxam, epoxiconazol + piraclostrobina e carbendazim tiveram os maiores efeitos residuais, e mantiveram o controle da doença por até 56 dias após sua aplica ção. Os triazóis utilizados para o controle da ferrugem também são eficientes para o controle da cercosporiose do cafeeiro.

Efeito de fungicidas triazóis sobre o controle da cercosporiose em mudas de cafeeiro / Effectiveness of triazole fungicides for the control of brown eye spot on coffee seedlings

Fungicidas do grupo dos triazóis e suas misturas com inseticidas são convencionalmente empregados para o controle da ferrugem e do bicho mineiro na cultura do cafeeiro. Neste estudo avaliou-se o efeito desses produtos sobre o controle da cercosporiose, causada por Cercospora coffeicola, outra importante doença do cafeeiro. Três experimentos foram realizados em casa de vegetação com mudas de cafeeiro da cultivar Mundo Novo IAC 501, sendo os produtos aplicados na parte aérea e no substrato. Os produtos aplicados na parte aérea foram: epoxiconazol, epoxiconazol + piraclostrobina, tetraconazol, ciproconazol, oxicloreto de cobre, azoxistrobina e carbendazim e no substrato: ciproconazol + tiametoxam, triadimenol + dissulfotom e triadimenol. Testemunhas sem tratamento químico também foram incluídas nos três experimentos. As mudas foram inoculadas com suspensões preparadas com cinco isolados de C. coffeicola (3-4 conídios/mL). A incidência e a severidade da doença foram avaliadas de 20 até 56 dias após as inoculações. Com exceção do oxicloreto de cobre, todos os demais tratamentos foram eficientes no controle da cercosporiose. Os triazóis, com exceção do tetraconazol, apresentaram sintomas reversíveis de fitotoxicidade. Os produtos: ciproconazol + tiametoxam, epoxiconazol + piraclostrobina e carbendazim tiveram os maiores efeitos residuais, e mantiveram o controle da doença por até 56 dias após sua aplica ção. Os triazóis utilizados para o controle da ferrugem também são eficientes para o controle da cercosporiose do cafeeiro.

Triazole fungicides and their mixtures with insecticides are usually employed for the control of coffee rust and leaf miner in coffee crops. In this study these chemicals were evaluated for the control of brown eye spot, caused by Cercospora coffeicola, another important disease of this crop. Three experiments were carried out in a greenhouse with coffee seedlings of the cultivar Mundo Novo IAC 501. The fungicides epoxiconazole, epoxiconazole + pyraclostrobin, tetraconazole, ciproconazole, copper oxychloride, azoxystrobin and carbendazim were applied to the leaves of coffee seedlings, and ciproconazole + tiametoxam, triadimenol + dissulfotom, and triadimenol were applied to the seedlings substrate. Controls were also included in all experiments. The seedlings were inoculated with suspensions prepared with a mixture of five C. coffeicola isolates (3-4 conidia/mL). The incidence and severity of the disease were evaluated 20 to 56 days after the inoculations. With the exception of copper oxychloride, all products were efficient for the control of brown eye spot. The triazoles, with the exception of tetraconazole, showed reversible phytotoxic effects. Ciproconazole + tiametoxam, epoxiconazole + pyraclostrobin and carbendazim had the highest residual effects and maintained small levels of the disease until 56 days after their application. The triazoles used for the control of coffee rust are also effective for the control of brown eye spot.

Morfologia, funções dos soros e variações dos ciclos vitais das ferrugens

ABSTRACT The organisms that are generically called rusts form an ample and complicated group. More than 100 genera that include about 6000 species are known today. In Brazil only about 1000 species belonging to 55 genera are known. The rusts belong to the group of fungus organisms, and are very old. Under the biological point of view, there is no doubt that the rusts have been successful, having been able to parasite for such a long period, and with such a varied geographic distribution. This must be due to the fact that they are capable of producing diverse spore forms that are involved in many complex types of life cycles. Thus, these variations provide the rusts with surprising abilities of adaptation in different environmental conditions.

RESUMO Os organismos vivos que são genericamente denominados ferrugens formam um amplo e complicado grupo. Mais de 100 gêneros que incluem cerca de 6.000 espécies são hoje conhecidos. Somente no Brasil são conhecidas cerca de 1.000 espécies pertencendo a 55 gêneros diferentes. As ferrugens pertencem ao grupo de organismos comumente denominados fungos, são organismos muito antigos. Sob o ponto de vista biológico, não há dúvidas de que as ferrugens foram bem sucedidas, tendo sido capazes de parasitar por um período tão longo, e com uma distribuição geográfica tão variada. Isso se deve ao fato de elas serem capazes de produzir diversas formas esporíferas que estão envolvidas em muito tipos complexos de ciclos de vida. Assim, essas variações permitem às ferrugens habilidades surpreendentes de adaptação em diferentes condições ambientais.

Bioprospecting endophytic bacteria for biological control of coffee leaf rust

Suppression of plant diseases due to the action of endophytic microorganisms has been demonstrated in several pathosystems. Experiments under controlled conditions involving endophytic bacteria isolated from leaves and branches of Coffea arabica L and Coffea robusta L were conducted with the objective of evaluating the inhibition of germination of Hemileia vastatrix Berk. & Br., race II, urediniospores and the control of coffee leaf rust development in tests with leaf discs, detached leaves, and on potted seedling of cv. Mundo Novo. The endophytic bacterial isolates tested proved to be effective in inhibiting urediniospore germination and/or rust development, with values above 50%, although the results obtained in urediniospore germination tests were inferior to the treatment with fungicide propiconazole. Endophytic isolates TG4-Ia, TF2-IIc, TF9-Ia, TG11-IIa, and TF7-IIa, demonstrated better coffee leaf rust control in leaf discs, detached leaves, and coffee plant tests. The endophytic isolates TG4-Ia and TF9-Ia were identified as Bacillus lentimorbus Dutky and Bacillus cereus Frank. & Frank., respectively. Some endophytic bacterial isolates were effective in controlling the coffee leaf rust, although some increased the severity of the disease. Even though a relatively small number of endophytic bacteria were tested, promising results were obtained regarding the efficiency of coffee leaf rust biocontrol. These selected agents appears to be an alternative for future replacement of chemical fungicide.

Supressão de doenças de plantas por microrganismos endofíticos tem sido demonstrada em diversos patossistemas. Neste trabalho foram selecionados isolados de bactérias endofíticas de folhas e ramos de cafeeiro com potencial para o controle biológico da ferrugem do cafeeiro, pois é conhecido que esses microrganismos podem possuir essa característica. Bactérias endofíticas isoladas previamente de folhas e ramos de Coffea arabica L e Coffea robusta L foram avaliadas quanto ao seu potencial de biocontrole da ferrugem do café causada pelo fungo Hemileia vastatrix Berk. & Br., raça 2. As bactérias foram testadas para a inibição da germinação de urediniosporos do fungo e em bioensaios para o controle do desenvolvimento da ferrugem alaranjada do cafeeiro em discos de folhas, folhas destacadas e mudas da cv. Mundo Novo. Os isolados de bactérias endofíticas testados demonstraram eficácia na inibição da germinação de urediniosporos e/ou no desenvolvimento da ferrugem, com valores acima de 50%, embora os resultados obtidos nos testes de germinação de urediniosporos tenham sido inferiores ao tratamento com propiconazole (testemunha padrão). Nos testes em discos de folhas, folhas destacadas e em plantas de cafeeiro, os isolados endofíticos TG4-Ia, TF2-IIc, TF9-Ia, TG11-IIa e TF7-IIa demonstraram melhor controle da ferrugem do cafeeiro. Os isolados endofíticos TG4-Ia e TF9-Ia foram identificados como Bacillus lentimorbus Dutky e Bacillus cereus Frank. & Frank., respectivamente. De acordo com os resultados verifica-se que alguns isolados foram eficientes em controlar a ferrugem do cafeeiro, embora alguns tenham aumentado a severidade da doença. Apesar do número relativamente baixo de bactérias endofíticas testadas, resultados promissores foram obtidos em relação ao controle biológico da ferrugem, sendo que esses poderão no futuro apresentar uma alternativa aos fungicidas.

Bioprospecting endophytic bacteria for biological control of coffee leaf rust

Suppression of plant diseases due to the action of endophytic microorganisms has been demonstrated in several pathosystems. Experiments under controlled conditions involving endophytic bacteria isolated from leaves and branches of Coffea arabica L and Coffea robusta L were conducted with the objective of evaluating the inhibition of germination of Hemileia vastatrix Berk. & Br., race II, urediniospores and the control of coffee leaf rust development in tests with leaf discs, detached leaves, and on potted seedling of cv. Mundo Novo. The endophytic bacterial isolates tested proved to be effective in inhibiting urediniospore germination and/or rust development, with values above 50%, although the results obtained in urediniospore germination tests were inferior to the treatment with fungicide propiconazole. Endophytic isolates TG4-Ia, TF2-IIc, TF9-Ia, TG11-IIa, and TF7-IIa, demonstrated better coffee leaf rust control in leaf discs, detached leaves, and coffee plant tests. The endophytic isolates TG4-Ia and TF9-Ia were identified as Bacillus lentimorbus Dutky and Bacillus cereus Frank. & Frank., respectively. Some endophytic bacterial isolates were effective in controlling the coffee leaf rust, although some increased the severity of the disease. Even though a relatively small number of endophytic bacteria were tested, promising results were obtained regarding the efficiency of coffee leaf rust biocontrol. These selected agents appears to be an alternative for future replacement of chemical fungicide.

Supressão de doenças de plantas por microrganismos endofíticos tem sido demonstrada em diversos patossistemas. Neste trabalho foram selecionados isolados de bactérias endofíticas de folhas e ramos de cafeeiro com potencial para o controle biológico da ferrugem do cafeeiro, pois é conhecido que esses microrganismos podem possuir essa característica. Bactérias endofíticas isoladas previamente de folhas e ramos de Coffea arabica L e Coffea robusta L foram avaliadas quanto ao seu potencial de biocontrole da ferrugem do café causada pelo fungo Hemileia vastatrix Berk. & Br., raça 2. As bactérias foram testadas para a inibição da germinação de urediniosporos do fungo e em bioensaios para o controle do desenvolvimento da ferrugem alaranjada do cafeeiro em discos de folhas, folhas destacadas e mudas da cv. Mundo Novo. Os isolados de bactérias endofíticas testados demonstraram eficácia na inibição da germinação de urediniosporos e/ou no desenvolvimento da ferrugem, com valores acima de 50%, embora os resultados obtidos nos testes de germinação de urediniosporos tenham sido inferiores ao tratamento com propiconazole (testemunha padrão). Nos testes em discos de folhas, folhas destacadas e em plantas de cafeeiro, os isolados endofíticos TG4-Ia, TF2-IIc, TF9-Ia, TG11-IIa e TF7-IIa demonstraram melhor controle da ferrugem do cafeeiro. Os isolados endofíticos TG4-Ia e TF9-Ia foram identificados como Bacillus lentimorbus Dutky e Bacillus cereus Frank. & Frank., respectivamente. De acordo com os resultados verifica-se que alguns isolados foram eficientes em controlar a ferrugem do cafeeiro, embora alguns tenham aumentado a severidade da doença. Apesar do número relativamente baixo de bactérias endofíticas testadas, resultados promissores foram obtidos em relação ao controle biológico da ferrugem, sendo que esses poderão no futuro apresentar uma alternativa aos fungicidas.

Avaliação de genótipos dos cafeeiros Arabica e Robusta na Amazônia Ocidental

The behavior of 16 genotypes of coffee (C. arabica and C. canephora) was evaluated in the edaphoclimatic conditions of the state of Acre. The genotypes came from the extinct Brazilian Coffee Institute (Natividade, RJ). The experiment was conducted at Embrapa Acre, Rio Branco, AC, in the period from 1989 to 1996, in a randomized block design, with five repetitions. The characteristics studied were yield of "cherry" fruits and coffee beans, vigor, total height, stem diameter and phytossanitary conditions. The Icatu PR 182039-1 and Conilon ES genotypes showed higher average yield of beans, with 4.345 and 4.147 kg/ha, respectively, followed by Catuaí SH1 EP57C-260, Mundo Novo and Catuaí SH1 EP57C-166, with yields above 2.800 kg/ha. Mundo Novo and Catuaí Amarelo presented higher incidence of Hemileia vastratrix, and Catuaí EP 57-C-260 and Catuaí EP57 C-166 were more susceptible to Pellicularia koleroga. Icatu PR 182039-1, Conilon ES and Catuaí SH1 EP57C-260 were superior to the other genotypes with respect to plant vigor, yield capacity, appearance of the cherries and beans, and show promise for cultivation in the state of Acre.

Avaliou-se o comportamento de 16 genótipos de cafeeiros das espécies C. arabica e C. canephora nas condições edafoclimáticas do estado do Acre. Os genótipos utilizados foram provenientes do extinto Instituto Brasileiro do Café (Natividade, RJ). O experimento foi conduzido no campo experimental da Embrapa Acre, Rio Branco, AC, no período de 1989 a 1996, num delineamento experimental de blocos casualizados, com 5 repetições. As características estudadas foram: produção de café em cereja e côco, vigor, altura da planta, diâmetro do caule e aspectos fitossanitários. Os genótipos Icatu PR182039-1 e Conilon ES foram os que apresentaram as maiores produções médias de café côco, 4.345 e 4.147 kg/ha, respectivamente, e em seguida vieram o Catuaí SH1 EP57C-260, Mundo Novo e Catuaí SH1 EP57C-166, todos com produção acima de 2.800 kg/ha. Quanto a incidência de ferrugem (Hemileia vastratrix), os genótipos Mundo Novo e Catuaí Amarelo apresentaram maior incidência, e os mais susceptíveis a queima do fio (Pellicularia koleroga) foram Catuaí EP 57-C-260 e Catuaí EP57 C-166. Os genótipos Icatu PR 182039-1, Conilon ES e Catuaí SH1 EP57C-260 foram superiores aos demais genótipos quanto a capacidade produtiva, bom aspecto dos frutos e grãos, mostrando-se promissores para o cultivo no Estado do Acre.

Avaliação de genótipos dos cafeeiros Arabica e Robusta na Amazônia Ocidental

The behavior of 16 genotypes of coffee (C. arabica and C. canephora) was evaluated in the edaphoclimatic conditions of the state of Acre. The genotypes came from the extinct Brazilian Coffee Institute (Natividade, RJ). The experiment was conducted at Embrapa Acre, Rio Branco, AC, in the period from 1989 to 1996, in a randomized block design, with five repetitions. The characteristics studied were yield of "cherry" fruits and coffee beans, vigor, total height, stem diameter and phytossanitary conditions. The Icatu PR 182039-1 and Conilon ES genotypes showed higher average yield of beans, with 4.345 and 4.147 kg/ha, respectively, followed by Catuaí SH1 EP57C-260, Mundo Novo and Catuaí SH1 EP57C-166, with yields above 2.800 kg/ha. Mundo Novo and Catuaí Amarelo presented higher incidence of Hemileia vastratrix, and Catuaí EP 57-C-260 and Catuaí EP57 C-166 were more susceptible to Pellicularia koleroga. Icatu PR 182039-1, Conilon ES and Catuaí SH1 EP57C-260 were superior to the other genotypes with respect to plant vigor, yield capacity, appearance of the cherries and beans, and show promise for cultivation in the state of Acre.

Avaliou-se o comportamento de 16 genótipos de cafeeiros das espécies C. arabica e C. canephora nas condições edafoclimáticas do estado do Acre. Os genótipos utilizados foram provenientes do extinto Instituto Brasileiro do Café (Natividade, RJ). O experimento foi conduzido no campo experimental da Embrapa Acre, Rio Branco, AC, no período de 1989 a 1996, num delineamento experimental de blocos casualizados, com 5 repetições. As características estudadas foram: produção de café em cereja e côco, vigor, altura da planta, diâmetro do caule e aspectos fitossanitários. Os genótipos Icatu PR182039-1 e Conilon ES foram os que apresentaram as maiores produções médias de café côco, 4.345 e 4.147 kg/ha, respectivamente, e em seguida vieram o Catuaí SH1 EP57C-260, Mundo Novo e Catuaí SH1 EP57C-166, todos com produção acima de 2.800 kg/ha. Quanto a incidência de ferrugem (Hemileia vastratrix), os genótipos Mundo Novo e Catuaí Amarelo apresentaram maior incidência, e os mais susceptíveis a queima do fio (Pellicularia koleroga) foram Catuaí EP 57-C-260 e Catuaí EP57 C-166. Os genótipos Icatu PR 182039-1, Conilon ES e Catuaí SH1 EP57C-260 foram superiores aos demais genótipos quanto a capacidade produtiva, bom aspecto dos frutos e grãos, mostrando-se promissores para o cultivo no Estado do Acre.

Agronomic characterization and responses to coffeeleaf rust in coffee progenies resistant to the gall nematode Meloidogyne exigua / Caracterização agronômica e reação à ferrugem de progênies de cafeeiro resistentes a Meloidogyne exigua

The aim of this study was to determine agronomic characteristics and responses to the coffee leaf rust fungus (Hemileia vastatrix Berk. et Br.) in coffee progenies resistant to the gall nematode Meloidogyne exigua. The experiment was conducted in December 2000 at Ouro Verde Farm (FazendaOuro Verde), located in the municipality of Campos Altos – Minas Gerais (MG). Ten F3:4 progenies were evaluated. They were derived from crosses between CIFC 2570 Timor Hybrid selections and Catuaí cultivars known to be resistant to M. exigua. The Catuaí Vermelho IAC 99 cultivar served as a control. A randomized block design with three replicates was used. In total, there were thirty-three plots consisting of eight plants each. The following characteristics were assessed between the harvests of 2011/2012 and 2014/2015: (a) yield expressed as processed coffee bags ha-1; (b) rust incidence and severity; (c) vegetative vigor; (d) percentage of coffee fruits at the “cherry” stage; (e) percentage of floaters; (f) crown diameter; (g) percentage of coffee beans of size sieve 17 and higher; and (h) sensory analysis of the coffee beverage. The results indicated the following: (a) the H514-7-14-2, H514-7-4-5, H493- 1-2-2, H514-7-16-3, H514-7-8-11, H518-2-10-1, and H514-5-2-4 progenies were the most productive; (b) all progenies showed promising resistance to coffee leaf rust; (c) all genotypes had the potential for specialty coffee production; (d) the H493-1-2-2 progeny showed resistance both to rust and the nematode, and has good potential for specialty coffee production; and (e) the yields of the H514-7-8-11, H518-2-10-1, H514-5-2-4, H514-7-16-3, H514-7-14-2, H514-7-4-5, and H493-1-2-2 progenies were significantly higher than that of the Catuaí IAC 99 control.

O objetivo deste trabalho foi disponibilizar informações de características agronômicas e reação à ferrugem de progênies de cafeeiro resistentes a M. exigua. O experimento foi instalado em dezembro de 2000, na Fazenda Ouro Verde, situada no município de Campos Altos – MG. Foram avaliadas 10 progênies F3:4 oriundas do cruzamento entre seleções de Híbrido de Timor provenientes do CIFC 2570 e cultivares do grupo Catuaí, previamente selecionadas como resistentes a M. exigua, e a cultivar Catuaí Vermelho IAC 99 como testemunha. Utilizou-se delineamento de blocos ao acaso, com três repetições, totalizando 33 parcelas constituídas de oito plantas cada. Entre as safras 2011/2012 a 2014/2015 foram avaliadas as seguintes características: produtividade em sacas de café beneficiado ha-1, incidência e severidade da ferrugem, vigor vegetativo, porcentagem de frutos no estádio “cereja”, porcentagem de frutos chochos, diâmetro de copa, porcentagem de grãos peneira 17 e acima e análise sensorial de bebida. Diante dos resultados pode-se concluir que: as progênies H514-7-14-2, H514-7-4-5, H493-1- 2-2, H514-7-16-3, H514-7-8-11, H518-2-10-1 e H514-5-2-4 são as mais produtivas; todas as progênies apresentam comportamento promissor para resistência à ferrugem do cafeeiro; todos os genótipos apresentam potencial para a produção de cafés especiais; a progênie H493-1-2-2 se mostra promissora apresentando resistência à ferrugem e ao nematóide além de apresentar bom potencial produtivo; e as progênies H514-7-8-11, H518-2-10-1, H514-5-2-4, H514-7-16-3, H514-7-14-2, H514-7-4-5 e H493-1- 2-2 tiveram produtividade estatisticamente superior à testemunha Catuaí IAC 99.

Eficiência do controle de nematóides, ferrugem e bicho mineiro em cafeeiros

Danos aos cafeeiros são causados pela ferrugem, bicho mineiro e nematóides. Foram objetivos deste trabalho efetuar um levantamento quantitativo dos nematóides em uma propriedade cafeeira, caracterizar duas situações distintas de nematóides no cafeeiro e avaliar a eficiência do controle químico em ambas as situações. Uma propriedade cafeeira foi amostrada em áreas de um hectare que foram estratificadas conforme o nível de infestação de Meloidogyne sp. Numa área com alta infestação foi conduzido um experimento para avaliar a eficiência de produtos químicos no controle dos nematóides, ferrugem e bicho mineiro. O mesmo experimento foi feito em outra área distinta desta em relação à localização, idade das plantas e aos nematóides. Os resultados mostraram ampla ocorrência de Meloidogyne sp. nos cafezais com a predominância de apenas uma espécie. Na segunda área foram detectados no cafeeiro Meloidogyne exigua, M. coffeicola, M. paranaensis e Meloidogyne sp. Foram observadas diferenças significativas de controle entre os tratamentos. O melhor controle da ferrugem, em cafeeiros novos, foi obtido com a aplicação ao solo dos produtos e, nos cafeeiros velhos, a pulverização foliar foi significativamente superior. Quando os níveis populacionais de Meloidogyne spp. foram reduzidos obteve-se maior concentração de triadimenol nas folhas do cafeeiro, menor severidade da doença e maior produção

The main problems of the coffee crop are caused by rust, coffee leaf miner and nematodes. The purposes of this experiment were to do a survey of nematodes in a farm with coffee plantations, characterize two distinct situations involving nematodes in the coffee plant and evaluate comparatively the efficiency of chemical control in both situations. Samples were collected in areas of approximately one hectare, the nematodes were removed in the laboratory and the areas were classified in terms of the level of infestation of Meloidogyne sp. Based on this, one area, with high level of infestation, was selected. An experiment was conducted for three years in this particular area to evaluate the efficiency of the application of chemicals for the control of nematodes, rust and coffee leaf miner. At the same time, the same experiment was conducted in a different area regarding localization, age of the plants and of the nematodes. The results showed a great occurrence of Meloidogyne sp. in the coffee plantations of the farm, only one new species of root-knot nematodes being predominant. In the second experimental area were detected Meloidogyne exigua, M. coffeicola, M. paranaensis and Meloidogyne sp. in the coffee plant and M. javanica in Amaranthus sp. The results of the chemical control showed significant differences between the treatments. However, in the new coffee plantations, the best control of rust was obtained with the application of the products on the ground. In the old coffee plantations, the leaf spraying was significantly superior. When population levels of Meloidogyne spp. were brought down, it has been observed a larger concentration of triadimenol on the leaves of the coffee plant, one could also notice that rust was less severe and the result was a larger production of coffee

Estudo sobre o controle da ferrugem do cafe Hemileia Vastatrix Berk. Et Br. com o emprego de fungicidas veiculados em óleos minerais

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Contribuição ao estudo ecológico da ferrugem do cafeeiro (Hemileia vastatrix Berk et Br.) em diferentes populações de Coffea arabica L. da região de Pindorama - SP, Brasil

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