Caracterização e expressão transiente de genes de Phakopsora pachyrhizi que codificam proteínas secretadas

• Ano de defesa: 2010
• Autor(a) principal: Costa, Poliene Martins
• Orientador(a): Brommonschenkel, Sérgio Hermínio
• Banca de defesa: Pereira, Olinto Liparini , Correa Junior, Ary
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Viçosa
• Programa de Pós-Graduação: Mestrado em Fitopatologia
• Departamento: Etiologia; Epidemiologia; Controle
• País: BR
• Palavras-chave em Português: Phakopsora pachyrhizi; Ferrugem-da-soja; Soja
• Palavras-chave em Inglês: Phakopsora pachyrhizi; Crown rust soybean; Soybean
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOSSANIDADE::FITOPATOLOGIA
• Link de acesso: http://locus.ufv.br/handle/123456789/4431

Rust fungi secrete and translocate proteins into the cytoplasm of plant cells during host-parasite interaction. Nowadays, it s known that Avr genes encode effector proteins that are recognized by proteins encoded by R genes. However, it s still unknown the nature and the function of Avr genes of the fungus Phakopsora pachyrhizi. Recently, the use of the Yeast Secretion Trap system allowed the identification of partial sequences of cDNAs that encode proteins secreted by the monopustular isolate PPUFV02 of P. pachyrhizi. In order to keep on the secretome characterization of this isolate to identify Avr genes, this work was developed with two purposes: (1) to evaluate and to characterize the reaction of 33 soybean genotypes to P. pachyrhizi monopustular isolate PPUFV02 in order to support future functional studies of candidate Avr genes, (2) to obtain the complete sequence and analyse the transient expression in tobacco of six genes from P. pachyrhizi monopustular isolate PPUFV02 that encode secreted proteins. The isolate PPUFV02 was avirulent in the soybean genotypes PI 594538-A, PI 230970, PI 459025, PI 200487 and PI 471904 which contain, respectively, the resistance genes Rpp1b, Rpp2, Rpp4, Rpp5. The resistance of these genotypes was detected by RB lesions. We also verified the occurrence of RB lesions in the soybean genotypes PI 587880-A, PI 594767-A, PI 561356, PI 587905 and the absence of symptoms in PI 594754 genotype after the inoculation with isolate PPUFV02 of P. pachyrhizi. It was obtained the complete sequences of six genes that encode secreted proteins. They presented typical characteristics of effectors as small proteins (<400 aa) with unknown function, proteins with secretion signal peptide at the N-terminal region and some of the proteins with cysteine residues that could form disulfide bonds. Preliminary studies of agroinfiltration in tobacco revealed that three genes encode proteins able to induce necrosis in this plant. This result is consistent with the mechanism of P. pachyrhizi pathogenesis. However, further studies are needed to confirm the results obtained in tobacco and to verify whether the same results are obtained in other non-host plants and in soybean.