Open AccessFungal cellulase is an elicitor but its enzymatic activity is not required for its elicitor activity
Author(s) -
Ma Yanan,
Han Chao,
Chen Jinyin,
Li Haiyun,
He Kun,
Liu Aixin,
Li Duochuan
Publication year - 2015
Publication title -
molecular plant pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.945
H-Index - 103
eISSN - 1364-3703
pISSN - 1464-6722
DOI - 10.1111/mpp.12156
Subject(s) - elicitor , cellulase , biology , biochemistry , potato virus x , wild type , rhizoctonia solani , plant defense against herbivory , microbiology and biotechnology , enzyme , mutant , gene , botany , rna
Summary Plant‐pathogenic fungi produce cellulases. However, little information is available on cellulase as an elicitor in plant–pathogen interactions. Here, an endocellulase ( EG 1) was isolated from R hizoctonia solani . It contains a putative protein of 227 amino acids with a signal peptide and a family‐45 glycosyl hydrolase domain. Its aspartic acid ( A sp) residue at position 32 was changed to alanine ( A la), resulting in full loss of its catalytic activity. Wild‐type and mutated forms of the endoglucanase were expressed in yeast and purified to homogeneity. The purified wild‐type and mutant forms induced cell death in maize, tobacco and A rabidopsis leaves, and the transcription of three defence marker genes in maize and tobacco and 10 genes related to defence responses in maize. Moreover, they also induced the accumulation of reactive oxygen species ( ROS ), medium alkalinization, Ca 2+ accumulation and ethylene biosynthesis of suspension‐cultured tobacco cells. Similarly, production of the EG 1 wild‐type and mutated forms in tobacco induced cell death using the Potato virus X ( PVX ) expression system. In vivo , expression of EG 1 was also related to cell death during infection of maize by R. solani . These results provide direct evidence that the endoglucanase is an elicitor, but its enzymatic activity is not required for its elicitor activity.