Genome-Wide Analysis of Microsatellites in Alternaria arborescens and Elucidation of the Function of Polyketide Synthase (PksJ).

Microsatellites or simple sequence repeats (SSRs) have been the most widely applied class of molecular markers used in genetic studies, having applications in genetic conservation, population studies, as well as diagnostics of fungi. Mining and analysis of SSRs of the whole genome sequence have been carried out in this study for the fungus Alternaria arborescens causing early blight of tomato and well known for producing mycotoxins like alternariol (AOH), alternariol monomethyl ether (AME), etc. A total of 4097 microsatellites were identified in A. Arborescens genome. Contig 1 was identified as the most SSR-rich region which was further analyzed to correlate the presence of SSRs with different biological processes. A total of 246 putative genes were predicted in this study and KEGG pathway analysis of 155 predicted genes indicated that SSRs can be linked with important metabolic pathways, molecular functioning, signal transduction, and cellular processes. The prediction of fungal mycotoxin inducer gene Polyketide synthase (PksJ) linked with SSR in this study may be a potential candidate participating in oncogenic signal transduction in human. Our study is the first report of PksJ gene in A. arborescens, a precursor of AOH and AME.