Manoel Teixeira Souza Júnior

Development of virus resistant transgenic papayas expressing the coat protein gene from a Brazilian isolate of Papaya ringspot virus

Translatable and nontranslatable versions of the coat protein (cp) gene of a Papaya ringspot virus (PRSV) isolate collected in the state of Bahia, Brazil, were engineered for expression in Sunrise and Sunset Solo varieties of papaya (Carica papaya). The biolistic system was used to transform secondary somatic embryo cultures derived from immature zygotic embryos. Fifty-four transgenic lines, 26 translatable and 28 nontranslatable gene versions, were regenerated, with a transformation efficiency of 2.7%. Inoculation of cloned R0 plants with PRSV BR, PRSV HA or PRSV TH, Brazilian, Hawaiian and Thai isolates, respectively, revealed lines with mono-, double-, and triple-resistance. After molecular analysis and a preliminary agronomic evaluation, 13 R1 and R2 populations were incorporated into the papaya-breeding program at Embrapa Cassava and Tropical Fruits, in Cruz das Almas, Bahia, BrazilVersoes traduziveis e nao traduziveis do gene da capa proteica (cp) de um isolado de Papaya ringspot virus (PRSV) coletado no Estado da Bahia, Brasil, foram produzidas para expressao nas variedades Sunrise e Sunset Solo de mamoeiro (Carica papaya). O sistema de biobalistica foi utilizado para transformar embrioes somaticos secundarios derivados de embrioes zigoticos imaturos. Cinquenta e quatro linhas transgenicas, sendo 26 contendo versoes traduziveis e 28 contendo versoes nao traduziveis do gene cp foram regeneradas, o que resultou em 2,7% de eficiencia de transformacao, quando considerado o numero de linhas transgenicas obtidas por embriao zigotico imaturo excisado. Desafios de plantas R0 com PRSV BR, PRSV HA ou PRSV TH, respectivamente isolado brasileiro, havaiano e tailandes, revelaram linhas com resistencia a um, dois e tres isolados de PRSV. Apos analises moleculares e avaliacao agronomica preliminar, 13 populacoes R1 e R2 de mamoeiros transgenicos foram incorporadas ao programa de melhoramento genetico da Embrapa Mandioca e Fruticultura, em Cruz das Almas, Bahia, Brasil.

Scanning electron microscopy of the interaction between Cryptococcus magnus and Colletotrichum gloeosporioides on papaya fruit

The objective of this work was to investigate possible modes of action of the yeast Cryptococcus magnus in controlling anthracnose (Colletotrichum gloeosporioides) on post harvested papaya fruits. Scanning electron microscopy was used to analyze the effect of the yeast on inoculations done after harvest. Results showed that C. magnus is able to colonize wound surfaces much faster than the pathogen, outcompeting the later for space and probably for nutrients. In addition, C. magnus produces a flocculent matrix, which affects hyphae integrity. The competition for space and the production of substances that affect hyphae integrity are among the most important modes of action of this yeast.O objetivo deste trabalho foi investigar provaveis modos de acao da levedura Cryptococcus magnus , que resultam no controle da antracnose ( Colletotrichum gloeosporioides ) em frutos de mamoeiro na pos-colheita. A microscopia eletronica de varredura foi utilizada para avaliar o efeito da levedura sobre inoculacoes realizadas apos a colheita. Os resultados mostraram que C. magnus e capaz de colonizar a superficie de ferimentos nos frutos e vencer a competicao por espaco e, provavelmente, por nutrientes. Alem disso, C. magnus produz uma matriz de textura caracteristica que afeta a integridade da hifa do patogeno. A competicao por espaco e a producao de substâncias que afetam a integridade das hifas estao entre os mais importantes modos de acao desta levedura.

Diversidade genética de isolados de Ralstonia solanacearum e caracterização molecular quanto a filotipos e sequevares

The objective of this work was to identify Brazilian isolates of Ralstonia solanacearum according to phylotypes and sequevars, to determine their genetic diversity, to associate the pathogen genetic structure with its taxonomy and geographical origin, and to identify a specific molecular marker to diagnose banana moko disease. A group of 33 isolates of R. solanacearum, from the collection of Embrapa Tabuleiros Costeiros, collected from different plant hosts, was characterized using the repetitive extragenic palindromic sequence-based PCR (rep-PCR) and RAPD. From this group, 19 belonged to the pathogen race 2 and 14 to the race 1, and 15 isolates were associated with banana crop. Phylotypes and sequevars were characterized and determined by Multiplex PCR. It was verified that the isolates belonged to phylotypes II (82%) and III (12%). All isolates from banana plants belonged to phylotype II. The RAPD technique was efficient in grouping these isolates according to their geographical origin; however, it requires a large number of molecular markers. It was possible to establish the relationships among the isolates by rep-PCR. The enterobacterial repetitive intergenic consensus primer (ERIC) made it possible to separate the isolates according to the race, and the REP primer allowed for the discrimination among phylotypes.These were the two mostinformative analyses.

Advancing palm genomics by developing a high-density battery of molecular markers for Elaeis oleifera for future downstream applications

Background Although (Elaeis guineensis) is planted on only 5% of the total world vegetable oil acreage, it accounts for more than 30% of vegetable oil produced worldwide [1]. In Brazil, the Federal Government launched a plan to boost Oil Palm production as a way to meet the biofuels market increasing demand for vegetable oil. Nevertheless, the Oil Palm expansion areas in Brazil coincide with the area of occurrence of bud rot [2], a major disease that is decimating plantations already established in the area. In a way to circumvent such problem, breeders are now using E. oleifera germplasm in Oil Palm breeding programs, generating inter-specific hybrids not only resistant to bud rot, but with higher unsaturated fatty acid content, lower height [3]. E. oleifera, however, lack the genomic resources currently available for Oil Palm [1], hampering many possible studies that could potentially help breeding. Based on the foregoing, we started a project to develop a large set of molecular markers for the species based on the DArTSeq platform [4].

Microscopia eletrônica de varredura da interação entre Cryptococcus magnus e Colletotrichum gloeosporioides em frutos de mamão

The objective of this work was to investigate possible modes of action of the yeast Cryptococcus magnus in controlling anthracnose (Colletotrichum gloeosporioides) on post harvested papaya fruits. Scanning electron microscopy was used to analyze the effect of the yeast on inoculations done after harvest. Results showed that C. magnus is able to colonize wound surfaces much faster than the pathogen, outcompeting the later for space and probably for nutrients. In addition, C. magnus produces a flocculent matrix, which affects hyphae integrity. The competition for space and the production of substances that affect hyphae integrity are among the most important modes of action of this yeast.O objetivo deste trabalho foi investigar provaveis modos de acao da levedura Cryptococcus magnus , que resultam no controle da antracnose ( Colletotrichum gloeosporioides ) em frutos de mamoeiro na pos-colheita. A microscopia eletronica de varredura foi utilizada para avaliar o efeito da levedura sobre inoculacoes realizadas apos a colheita. Os resultados mostraram que C. magnus e capaz de colonizar a superficie de ferimentos nos frutos e vencer a competicao por espaco e, provavelmente, por nutrientes. Alem disso, C. magnus produz uma matriz de textura caracteristica que afeta a integridade da hifa do patogeno. A competicao por espaco e a producao de substâncias que afetam a integridade das hifas estao entre os mais importantes modos de acao desta levedura.