Genetic structure and proteomic analysis associated in potato to Rhizoctonia solani AG-3PT-stem canker and black scurf

Rhizoctonia solani AG-3PT is a necrotrophic plant pathogenic fungus affecting potato production globally. A total of 20 isolates of R. solani AG-3PT were subjected to pathogenicity tests, genetic diversity and proteomic analyses. The genetic diversity of R. solani AG-3PT isolates with different disease virulence was analyzed using 11 simple sequence repeats (SSR) primer pairs. Cluster analysis grouped the isolates into five main categories, indicating a high genetic diversity and recombination among the isolates, with no correlation between the groups and geographical origin. The protein pattern of 20 isolates of R. solani AG-3PT with different disease severity were analyzed by SDS-PAGE. Protein profiles were different that maybe associated with different levels of their aggressiveness. Based on the pathogenicity test results, isolates Rs-13 and Rs-4 were classified as virulent and least virulent, respectively. Here, we used proteomics strategy to compare mycelial proteins of virulent and least virulent isolates in order to further characterize them at the molecular level. The 2-DE results showed a differential expression of 27 protein spots, of which 11 well-focused protein spots were subjected to LC-MS-MS. The functions of the identified proteins indicated that they play roles in the fungal development, sporulation, carbohydrate metabolic process, lipid metabolic process, protein modification, and nucleotide metabolic process. The differences in pathogenicity between Rs-13 and Rs-4 isolate can be explained by differences in the expression levels of proteins involved in these pathways. The results of this research can enrich our knowledge about the virulence strategies of R. solani AG-3PT and provide useful information for the development of future fungicides. A combination of genetic diversity assessments of pathogen and understanding the biology and virulence mechanisms of pathogen, can help us in development of innovative and sustainable approaches to slow down the emergence of pathogen. • There are considerable variations in virulence among R. solani isolates. They were divided into 5 main groups. • 11 differentially expressed proteins were detected between virulent and least virulent isolates. • The abundance of proteins involved in pathogenicity and fast growth was higher in virulent isolate.