Search

Copyright of Colloquium Agrariae is the property of Asociacao Prudentina de Educacao e Cultura (APEC) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A molecular tool was adapted for practical identification of the world's first transgenic event (Embrapa 5.1) in common bean (Phaseolus vulgaris L.). Based on the technology of RNA interference and on the transformation of plants via the Biobalistic method, a transgenic bean was created with effective resistance to Bean golden mosaic virus, its principal virus. To support the monitoring of this technology, the development of new cultivars, and the process of producing, benefiting, and distributing of seeds and grains, a molecular detection tool based on loop‐mediated isothermal amplification (LAMP) was developed. This tool can facilitating diagnosis, making it fast, specific, low‐cost, and easily executed. Based on the gene Ahas (GenBank M88686) of the Embrapa 5.1 event, sets of initiators were planned (forward outer primer–backward outer primer and forward inner primer–backward inner primer) that are characteristic of the LAMP method. These were evaluated for their sensitivity and specificity in detecting their target. The LAMP method allows direct visual interpretation. The Neutral Red (NR) pH indicator was adopted to facilitate molecular diagnosis in moderately well equipped environments, thus reducing the risk of contamination and the need for skilled labor. This agility in diagnosis occurs because several phases commonly used in molecular techniques, such as polymerase chain reaction, can be excluded. The LAMP method, combined with a rapid DNA extraction method (modified NaOH) and the addition of NR, provides technological support for addressing issues of biosafety, traceability, and identification of the Embrapa 5.1 event in beans in the field and in industry. [ABSTRACT FROM AUTHOR]

Common bean (Phaseolus vulgaris L.) is the most important legume crop for direct human consumption in Brazil. Overall patterns of genetic diversity of common bean in the country are not well understood. Hence, this study sought to integrate morphological and agronomic evaluations with prior molecular diversity data from a geo-referenced collection of Brazilian common bean. Our sample included 279 randomly chosen landrace accessions from the main growing regions of beans in Brazil. Eighteen morphological and three agronomic characters (yield and susceptibility to common bacterial blight and rust diseases) were evaluated in field conditions in Brazil or California. Results show that the sample was diverse morphologically but did not include all the morphological variability described in domesticated common bean outside Brazil. Several accessions showed clear morphological differences in spite of having the same name. The integration of the current morphological and agronomic evaluations with a prior 74-marker diversity assessment of the same landraces improved the identification of five subpopulations identified on the basis of microsatellite diversity. These subpopulations could be distinguished by their morphology, the type and frequency of the market classes they included, and the frequency of susceptibility to diseases. This information will facilitate the management and use of P. vulgaris genetic diversity in Brazil. [ABSTRACT FROM AUTHOR]

In Brazil, the Cowpea mild mottle virus vectored by Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae), is an emerging threat for common bean (Phaseolus vulgaris L.; Fabaceae), including genetically modified elite bean lines developed for resistance to the Bean golden mosaic virus. To investigate this interaction, we quantified the susceptibility of 10 Bean golden mosaic virus-resistant lines to Cowpea mild mottle virus infection in 2 regions in Brazil with natural incidence of viruliferous B. tabaci. In 2 field trials, B. tabaci established on all varieties, but showed preference for the conventional cultivars 'Pérola' and 'BRS Pontal' when compared with elite lines (averaging > 400 nymphs per leaflet, and > 97% infection rate in 1 study). However, whereas elite lines were resistant to Bean golden mosaic virus, all became infected with Cowpea mild mottle virus. Highest infection rates (19 to 99% infected plants) occurred in genetically modified elite lines derived from BRS Pontal versus Pérola (12 to 16%). When comparing seed yield, most elite lines outperformed their conventional recurrent parent. On average, elite lines achieved relative yield increases between 199 and 1,045%, and the varieties CNFCT 16205 and CNFCT 16210 were the most productive in our field trials. Our results showed that the use of common bean cultivars resistant to golden mosaic is an important tool within integrated management strategies for whiteflies and viruses. However, further studies are needed to elucidate the threat of Cowpea mild mottle virus and the nature of whitefly interactions between these different viruses. No Brasil, o Cowpea mild mottle virus transmitido pela Bemisia tabaci (Genn.) (Hemiptera: Aleyrodidae), é uma ameaça emergente ao feijão comum (Phaseolus vulgaris L.; Fabaceae), incluindo as linhas elites de feijão geneticamente modificadas desenvolvidas para resistência ao Bean golden mosaic virus. Para investigar essa interação, quantificamos a suscetibilidade de dez linhas geneticamente modificadas resistentes ao Bean golden mosaic virus à infecção pelo Cowpea mild mottle virus em duas regiões do Brasil com incidência natural de B. tabaci virulíferas. Em dois ensaios de campo, B. tabaci estabeleceu em todas as variedades, mas mostrou preferência pelas cultivares convencionais 'Pérola' e 'BRS Pontal' quando comparadas com as linhas elite geneticamente modificadas (média > 400 ninfas por folíolo e > 97% taxa de infecção por virus em um dos estudos). No entanto, embora as linhas elite foram resistentes ao Bean golden mosaic virus, todas foram infectadas pelo Cowpea mild mottle virus. As maiores taxas de infecção (19 a 99% de plantas infectadas) ocorreram nas linhas elite geneticamente modificadas derivadas da BRS Pontal versus Pérola (12 a 16%). Ao comparar a produtividade, a maioria das linhas elite superou seu pai convencional recorrente. Os aumentos relativos de rendimento foi de 199 a 1.045% sendo as variedades CNFCT 16205 e CNFCT 16210 as mais produtivas. Nossos resultados mostraram que o uso de cultivares de feijão resistentes ao mosaico dourado é uma ferramenta importante dentro das estratégias integradas de manejo para moscas-brancas e vírus. No entanto, mais estudos são necessários para elucidar à ameaça do Cowpea mild mottle virus e a natureza das interações da mosca-branca com estes diferentes vírus. [ABSTRACT FROM AUTHOR]

BRS Ametista is a common bean cultivar with Carioca grain and yields similar to cultivar Pérola, but with larger grain size, resistance to anthracnose and Fusarium wilt. It is recommended for 18 states in all regions of Brazil and can be planted on over 95% of the area used for common bean in the country [ABSTRACT FROM AUTHOR]