The role of transcriptional activator Mg-XlnR in regulation of xylanases, cellulases and virulence of the rice blast fungus Magnaporthe oryzae
Keywords:Magnaporthe oryzae, rice blast, transcriptional activator, RNA silencing, virulence.
Transcriptional activator, XlnR, has been known to play an important role in regulation of cell wall degrading enzymes (CWDEs) in some pathogenic fungi. Here, we used RNA silencing to simultaneously knock-down the expression of two XlnR like genes (Mg-XlnR) in the genome of rice blast fungus Magnaporthe oryzae. Using Northern analysis, various levels of silencing of Mg-XlnR genes were observed in knock-down mutants compared with those in the wildtype. Moreover, the reduction of MG-XLNR mRNA observed in knock-down mutants resulted in the degradation of CWDEs mRNA and their extracellular enzymes such as xylanases and cellulases. The decrease of blast lesions and their expansion on infected leaves observed in silenced mutants indicated an important role of Mg-XlnR in regulation of CWDEs genes, particularly xylanases and virulence of the rice blast fungus.