The Functional Research Of MSADS-box Transcription Factor SsMCM1in Sclerotinia Sclerotiorum

Sclerotinia sclerotiorum (Lib.) de Bary is a notorious necrotrophic fungalpathogen with an extensive host range, endangering278families and more than450types of plants. Plant sclerotinia is caused by the fungus S. sclerotiorum, which is animportant cause of disease worldwide, resulting in huge economic losses.MADS-box proteins, a well-conserved family of transcription factors ineukaryotic organisms, specifically regulate a wide range of cellular functionsincluding primary metabolism, cell cycle and cell identity. However, little is knownabout roles of the MADS-box protein family in the fungal pathogen Sclerotiniasclerotiorum.In this research, the S. sclerotiorum MADS-box gene SsMCM1was cloned; itencodes a protein that is highly similar to Mcm1orthologues from Saccharomycescerevisiae and other fungi, and includes a highly conserved DNA-binding domain.SsMCM1is a member of the MADS box protein SRF (serum response factor)lineage. SsMCM1function was investigated using RNA interference. Silencedstrains were obtained using genetic transformation of the RNA interference vectorspS1-SsMCM1and pSD-SsMCM1. SsMCM1expression levels in silenced strainswere analyzed using RT-PCR. The results showed that SsMCM1mRNA expressionin these silenced strains was reduced to different degrees, and growth rate in thesesilenced strains was significantly decreased. Infecting tomato leaflets with silencedstrains indicated that SsMCM1was required for leaf pathogenesis in a susceptiblehost. Our results suggest that the MADS-box transcription factor SsMCM1isinvolved in S. sclerotiorum growth and virulence.