Small RNA profiling of Sclerotinia sclerotiorum while infecting Brassica napus

Mr Roshan Regmi1,2, Dr Toby  Newman1, Dr Lars Kamphuis1,2, Dr Mark Derbyshire1

1Centre for Crop and Disease Management, Curtin University, Perth, Australia, 2CSIRO Agriculture and Food, Floreat, Perth, Australia

Pathogen secrets different classes of molecules to infect its host. Recently, small RNA from the pathogen evolved as a new kind of pathogenicity factor during host infection. Sclerotinia sclerotiorum is a necrotroph fungus having broad host range. It incites Sclerotinia stem rot in Brassica napus (canola) and causes huge economic loses to canola industry annually in Australia and other canola growing part of the world. Despite new insights and efforts, limited fact is known about its molecular interaction with the host. To unravel the role of Sclerotinia small RNA in pathogenicity, we sequenced the small RNA from fungal mycelium while infecting Brassica napus leaves at 0, 12 and 24-time points. On an average, more than 60 M clean reads were obtained. The size class distribution enriched 22 nt length reads and 5 prime biased reads are uracils in those reads. We aligned those reads with the Sclerotinia genome and predicted the locus that has abundant 22 nt reads. The abundant putative small RNAs targets were identified in Brassica napus and Arabidopsis. We developed GFP transformed Sclerotinia strains to facilitate our sRNA knock out strains to accommodate in silico analysis with in vitro validation. The findings from this result would add more understanding on molecular mechanism of Sclerotinia sclerotiorum and Brassica napus patho-system.