EMS mutagenesis, selection and molecular characterization of soybean mutants with altered response to Phakopsora pachyrhizi

• Ano de defesa: 2019
• Autor(a) principal: Stock, Vinícius de Moura
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa; Fitopatologia
• Palavras-chave em Português: Ferrugem-da-soja; Glycine max; Metanossulfonato de etila; Genes; Soja; Ciências Agrárias
• Link de acesso: https://locus.ufv.br//handle/123456789/30077

The susceptibility and resistance of plants to microbial pathogens involves complex molecular interactions between the microbe’s effectors and the host’s targets. These effectors interact with host’s targets altering host cell metabolism, defense response and nutrient supply, favoring the parasitism. Therefore, loss or changes in these targets may limit the pathogen’s ability to cause disease. The objective of this study was to identify and characterize mutants from susceptible TMG4182 soybean variety with an altered response to P. pachyrhizi aiming to identify genes that encode effector targets. 1,820 M2 families obtained from soybean seeds treated with 0.3% (v / v) EMS for 16 hours were evaluated. Twenty-two seeds from each M2 families were planted in the greenhouse and evaluated for phenotypic variations. At the V1 stage, these plants were inoculated with P. pachyrhizi isolate PPUFV02 and screened for altered disease development phenotypes. From a total of 30,068 M2 plants evaluated, 2,976 displayed phenotypic variations in growth, plant architecture and leaf morphology, and 101 altered disease development. Plants from two M2 families, GMMT-509-20 and GMMT-504-04, displayed reddish-brown (RB) symptoms with less sporulation, while one, GMMT-496-01 presented necrotic lesions with fewer uredia and little sporulation. F2 segregation indicates that these phenotypes are determined by recessive genes. Whole-genome resequencing of ‘TMG4182’ and these mutants revealed a mutation frequency of approximately 1 variant nucleotide per 45,647 bases, 50% being base transitions from C to T and G to A. A total of 1,132 non-synonymous SNPs were detected in protein-coding genes. dCAPS assays also confirmed the presence of polymorphisms in plant defense-related genes: Glyma.03G220100, Glyma.18G046300, Glyma.03G049300, and Glyma.01G118900. However, these mutations were not associated with the mutant phenotypes. In future studies, Bulk segregant analysis and MutMap will be employed to identify the mutant genes.