Transcription factor that regulates sirodesmin production and contributes to virulence (PubMed:15387811, PubMed:18023597). Probably binds to the consensus motif TCGGN(3)CCGA found in the promoters of sirT, sirP, sirO, sirN, sirP, sirB, sirR, sirJ and sirQ (PubMed:18023597). Expressed during canola infection (PubMed:20507539). Expression is co-regulated with the other genes from the sirodesmin cluster and corresponds with sirodesmin production (PubMed:15387811). Leads to reduced production of sirodesmin PL and decreased transcription of sirodesmin PL biosynthetic genes (PubMed:18023597).