Glycoside hydrolase 28 family protein RsPG1 from Rhizoctonia solani motivates immune response to pathogen attack in different host plants.

Rhizoctonia solani is a necrotrophic pathogen causing rice sheath blight. Here, RsPG1, a glycosyl hydrolase encoding gene, was isolated from R. solani. Expression of RsPG1 was up-regulated upon R. solani infection in rice and by pectin treatment. Transient expression of RsPG1 in tobacco and tomato induced cell death response. RsPG1 encoded a protein belonging to glycosyl hydrolase family 28 and possessing pectinase activity. Infiltration of tobacco leaves with purified RsPG1 protein triggered cell death and up-regulated the transcription of CYP71D20, a pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) marker gene. Pretreatment of rice leaves with RsPG1 also up-regulated the transcription of PTI marker genes OsNPR3, OsPR1a and OsPR5, and promoted the resistance to R. solani infection. The residues of 18-260 and 181-361 in RsPG1 were essential for cell death induction in tobacco. Heat inactivation of RsPG1 protein led to failed cell death induction, up-regulated transcription of PTI marker genes CYP71D20, RBOHA and RBOHB, and improved resistance to R. solani infection in tobacco. Furthermore, the immunity response activity of RsPG1 was independent of the immunity receptors NbBAK1 and NbSOBIR1 in tobacco. These results indicate that RsPG1 is a typical elicitor secreted by R. solani that could trigger immune response in multiple plants.