Common bean reaction to angular leaf spot comprises transcriptional modulation of genes in the ALS10.1 QTL

Genetic resistance of common bean (Phaseolus vulgaris L.) against angular leaf spot (ALS), caused by the fungus Pseudocercospora griseola, is conferred by quantitative trait loci (OIL). In this study, we determined the gene content of the major OIL ALS10.1 located at the end of chromosome Pv10, and identified those that are responsive to ALS infection in resistant (CAL 143) and susceptible (IAC-UNA) genotypes. Based on the current version of the common bean reference genome, the ALS10.1 core region contains 323 genes. Gene Ontology (GO) analysis of these coding sequences revealed the presence of genes involved in signal perception and transduction, programmed cell death (PCD), and defense responses. Two putative R gene clusters were found at ALS10.1 containing evolutionary related coding sequences. Among them, the Phvu1.010G025700 was consistently up-regulated in the infected IAC-UNA suggesting its contribution to plant susceptibility to the fungus. We identified six other genes that were regulated during common bean response to P. griseola; three of them might be negative regulators of immunity as they showed opposite expression patterns during resistant and susceptible reactions at the initial phase of fungal infection. Taken together, these findings suggest that common bean reaction to F? griseola involves transcriptional modulation of defense genes in the ALS10.1 locus, contributing to resistance or susceptibility depending on the plant-pathogen interaction6COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIOR - CAPESFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP6899/10-22009/024112; 2010/51673-

Evidence for Strong Kinship Influence on the Extent of Linkage Disequilibrium in Cultivated Common Beans

Phaseolus vulgaris is an important grain legume for human consumption. Recently, association mapping studies have been performed for the species aiming to identify loci underlying quantitative variation of traits. It is now imperative to know whether the linkage disequilibrium (LD) reflects the true association between a marker and causative loci. The aim of this study was to estimate and analyze LD on a diversity panel of common beans using ordinary r2 and r2 extensions which correct bias due to population structure (rS2), kinship (rV2), and both (rVS2). A total of 10,362 single nucleotide polymorphisms (SNPs) were identified by genotyping by sequencing (GBS), and polymorphisms were found to be widely distributed along the 11 chromosomes. In terms of r2, high values of LD (over 0.8) were identified between SNPs located at opposite chromosomal ends. Estimates for rV2 were lower than those for rS2. Results for rV2 and rVS2 were similar, suggesting that kinship may also include information on population structure. Over genetic distance, LD decayed to 0.1 at a distance of 1 Mb for rVS2. Inter-chromosomal LD was also evidenced. This study showed that LD estimates decay dramatically according to the population structure, and especially the degree of kinship. Importantly, the LD estimates reported herein may influence our ability to perform association mapping studies on P. vulgaris

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

Divergence and genetic variability among superior rubber tree genotypes Divergência e variabilidade genética de genótipos superiores de seringueira

The objective of this work was to estimate the genetic variability and divergence among 22 superior rubber tree (Hevea sp.) genotypes of the IAC 400 series. Univariate and multivariate analyses were performed using eight quantitative traits (descriptors), including yield. In the univariate analyses, the estimated parameters were: genetic and environmental variances; genetic and environmental coefficients of variation; and the variation index. The Mahalanobis generalized distance, the Tocher agglomerative method and canonical variables were used for the multivariate analyses. In the univariate analyses, variability was verified among the genotypes for all the variables evaluated. The Tocher method grouped the genotypes into 11 clusters of dissimilarity. The first four canonical variables explained 87.93% of the cumulative variation. The highest genetic variability was found in rubber yield-related traits, which contributed the most to the genetic divergence. The most divergent pairs of genotypes are suggested for crossbreeding. The genotypes evaluated are suitable for breeding and may be used to continue the IAC rubber tree breeding program.<br>O objetivo deste trabalho foi estimar a divergência e a variabilidade genética entre 22 genótipos superiores de seringueira (Hevea sp.) da série IAC 400. Análises univariadas e multivariadas foram realizadas com oito caracteres quantitativos (descritores), incluindo produtividade. Na análise univariada, os parâmetros estimados foram: variâncias genética e ambiental, coeficientes de variação genética e ambiental, e índice de variação. A distância generalizada de Mahalanobis, o método aglomerativo de Tocher e variáveis canônicas foram utilizados nas análises multivariadas. Nas análises univariadas, verificou-se variabilidade entre os genótipos para todas as variáveis avaliadas. O método de Tocher agrupou os genótipos em 11 grupos de dissimilaridade. As quatro primeiras variáveis canônicas explicaram 87,93% da variação acumulada. A maior variabilidade genética foi encontrada em variáveis relacionadas à produtividade de borracha, que foram as que mais contribuíram para a divergência genética. Os pares de genótipos identificados como mais divergentes são indicados para cruzamentos. Os genótipos avaliados são adequados para o melhoramento genético e podem ser utilizados para continuar o programa de melhoramento da seringueira do IAC

Antixenosis of bean genotypes to Chrysodeixis includens (Lepidoptera: Noctuidae)

The objective of this work was to evaluate bean genotypes for resistance to soybean looper (Chrysodeixis includens). Initially, free-choice tests were carried out with 59 genotypes, divided into three groups according to leaf color intensity (dark green, light green, and medium green), in order to evaluate oviposition preference. Subsequently, 12 genotypes with high potential for resistance were selected, as well as two susceptible commercial standards. With these genotypes, new tests were performed for oviposition in a greenhouse, besides tests for attractiveness and consumption under laboratory conditions (26 +/- 2 degrees C, 65 +/- 10% RH, and 14 h light: 10 h dark photophase). In the no-choice test with adults, in the greenhouse, the &apos;IAC Jabola&apos;, Arcelina 1, &apos;IAC Boreal&apos;, &apos;Flor de Mayo&apos;, and &apos;IAC Formoso'genotypes were the least oviposited, showing antixenosis-type resistance for oviposition. In the free-choice test with larvae, Arcelina 4, &apos;BRS Horizonte&apos;, &apos;Perola&apos;, H96A102-1-1-1-52, &apos;IAC Boreal&apos;, &apos;IAC Harmonia&apos;, and &apos;IAC Formoso'were the less consumed genotypes, which indicates antixenosis to feeding. In the no-choice test, all genotypes (except for &apos;IAPAR 57&apos;) expressed moderate levels of antixenosis to feeding against C. includens larvae.O objetivo deste trabalho foi avaliar genótipos de feijoeiro quanto à resistência a lagarta-falsa-medideira (Chrysodeixis includens). Inicialmente, foram realizados testes com chance de escolha com 59 genótipos, divididos em três grupos, de acordo com a intensidade de coloração das folhas (verde-escura, verde-clara e verde-médio), para avaliar a preferência quanto à oviposição. Em seguida, selecionaram-se 12 genótipos com grande potencial de resistência, assim como dois padrões comerciais suscetíveis. Com estes genótipos, realizaram-se novos ensaios de oviposição, em casa de vegetação, além de testes de atratividade e consumo, em condições de laboratório (26±2ºC, 65±10% UR e fotófase de 14 h luz: 10 h escuro). No teste sem chance de escolha, com adultos, em casa de vegetação, os genótipos 'IAC Jabola', Arcelina 1, 'IAC Boreal', 'Flor de Mayo' e 'IAC Formoso' foram os menos ovipositados, tendo apresentado resistência do tipo antixenose à oviposição. No teste com chance de escolha, com larvas, Arcelina 4, 'BRS Horizonte', 'Pérola', H96A102-1-1-1-52, 'IAC Boreal', 'IAC Harmonia' e 'IAC Formoso' foram os genótipos menos consumidos, o que indica antixenose à alimentação. No teste sem chance de escolha, todos os genótipos (exceto 'IAPAR 57') expressaram níveis moderados de antixenose à alimentação de larvas de C. includens.Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq