Mapeamento de genes de resistência da soja à ferrugem asiática e análise transcricional na interação patógeno-hospedeiro
Data
2008-02-29
Autores
Silva, Danielle Cristina Gregorio da [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
A ferrugem asiática da soja é causada pelo fungo Phakopsora pachyrhizi. Quatro genes de resistência à ferrugem da soja distintos, Rpp1 a 4, foram descritos. O objetivo deste trabalho foi mapear geneticamente os genes de resistência Rpp2 e Rpp4 e identificar genes induzidos pela resposta de defesa mediada pelo gene Rpp2. Duas populações F2:3 derivadas dos cruzamentos entre as linhagens resistentes PI 230970 (Rpp2) e PI 459025 (Rpp4) com a cultivar suscetível BRS 184, e marcadores SSR, foram utilizados neste estudo. Os locos Rpp2 e Rpp4 foram mapeados nos grupos de ligação J e G da soja, respectivamente, e os marcadores associados terão grande valor no processo de seleção assistida por marcadores para este caráter. Quatro bibliotecas de cDNA, derivadas de folhas do genótipo resistente PI 230970 (Rpp2) e do genótipo suscetível Embrapa 48, obtidas às 24 e 192 horas após a inoculação com esporos de P. pachyrhizi, foram geradas utilizando a metodologia SSH e tiveram seu padrão de expressão avaliado por análise de microarranjos de cDNA. Foram produzidas 3.807 sequências viáveis, das quais 670 foram sequências únicas, sendo 149 destas (22,2%) novas sequências da soja. A categoria funcional mais representativa para as quatro bibliotecas foi proteção celular, defesa e virulência. Apenas 65 trnascritos foram diferencialmente expressos, estando eles envolvidos na geração de espécies reativas de oxigênio, fitoalexinas e proteínas antimicrobianas, morte celular e senescência, modificação, estabilização e degradação protéica, controle da expressão gênica e reforço de parede celular. Este trabalho permitiu a identificação de novas seqüências da soja e contribuiu para a elucidação da estratégia de defesa mediada pelo gene Rpp2.
Asian soybean rust is caused by the fungus Phakopsora pachyrhizi. Four resistance genes to this disease, Rpp1 to 4, were previously identified. The aim of this work was to identify SSR markers linked to Rpp2 and Rpp4, and to characterize genes up-regulated under soybean-Asian rust interaction. Two F2:3 populations derived from the crosses PI 230970 (Rpp2) x BRS 184 and PI 459025 (Rpp4) x BRS 184, and SSR markers were used for mapping. Rpp2 and Rpp4 loci were mapped on the soybean linkage groups J and G, respectively, and the associated markers will be highly valuable to assist the introduction of these genes into soybean cultivars. Four cDNA libraries derived from leaf samples of the resistant genotype PI 230970 and the susceptible genotype Embrapa 48, obtained at 24 and 192 hours after inoculation, were generated using SSH and evaluated by cDNA microarray analysis. A total of 3,807 reliable ESTs were obtained, 670 from them were unique. The most representative functional category in all libraries was “cell rescue, defense and virulence”. Only 65 transcripts were differentially expressed among treatments, and were involved in the generation of reactive oxygen species, phytoalexins and antimicrobial proteins; cell death and senescence; protein fate; gene expression control; and reinforcement of cell wall. This work produced novel soybean sequences and contributed to the comprehension of the soybean mechanism of resistance to Asian rust mediated by Rpp2.
Asian soybean rust is caused by the fungus Phakopsora pachyrhizi. Four resistance genes to this disease, Rpp1 to 4, were previously identified. The aim of this work was to identify SSR markers linked to Rpp2 and Rpp4, and to characterize genes up-regulated under soybean-Asian rust interaction. Two F2:3 populations derived from the crosses PI 230970 (Rpp2) x BRS 184 and PI 459025 (Rpp4) x BRS 184, and SSR markers were used for mapping. Rpp2 and Rpp4 loci were mapped on the soybean linkage groups J and G, respectively, and the associated markers will be highly valuable to assist the introduction of these genes into soybean cultivars. Four cDNA libraries derived from leaf samples of the resistant genotype PI 230970 and the susceptible genotype Embrapa 48, obtained at 24 and 192 hours after inoculation, were generated using SSH and evaluated by cDNA microarray analysis. A total of 3,807 reliable ESTs were obtained, 670 from them were unique. The most representative functional category in all libraries was “cell rescue, defense and virulence”. Only 65 transcripts were differentially expressed among treatments, and were involved in the generation of reactive oxygen species, phytoalexins and antimicrobial proteins; cell death and senescence; protein fate; gene expression control; and reinforcement of cell wall. This work produced novel soybean sequences and contributed to the comprehension of the soybean mechanism of resistance to Asian rust mediated by Rpp2.
Descrição
Palavras-chave
Soja, Genes de resistência, Transcritoma, Gycine max, Phakopsora pachyrhizi, Resistance genes, Transcriptone
Como citar
SILVA, Danielle Cristina Gregorio da. Mapeamento de genes de resistência da soja à ferrugem asiática e análise transcricional na interação patógeno-hospedeiro. 2008. xiv, 153 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2008.