The Bacterial Second Messenger c-di-GMP Metabolism Regulation and the Roles of Virulence

WEI Chao;YANG Jun;ZHANG Yuanbao;WANG Lei;SUN Wenxian;WANG Yunyue;Ministry of Education Key Laboratory for Agriculture Biodiversity and Plant Disease Management,Yunnan Agricultural University;Department of Plant Pathology and the Ministry of Agricultural Key Laboratory for Plant Pathology,China Agricultural University;

cyclic diguanylate;;receptor;;biofilm formation;;bacterial motility;;type III secretion system;;virulence

Cyclic diguanylate( c-di-GMP) is a novel and universal second messenger in bacteria. Cellular levels of c-di-GMP are fine-tuned through two categories of proteins,one is the diguanylate cyclases( DGC) that harbor the GGDEF domains and are responsible for the synthesis of c-di-GMP; the other is phosphodiesterases( PDE) that contain EAL or HD-GYP domains and are involved in the degradation of c-di-GMP. Several types of molecules function as c-di-GMP receptors,including PilZ-domain proteins,degenerate GGDEF or EAL domain-containing proteins,transcription factors and riboswitches. These receptors sense cellular levels of the dinucleotide and regulate the expression of specific downstream genes. The c-di-GMP molecule is involved in the regulation of various biological processes in bacteria including biofilm formation,motility,the production of exopolysaccharides,the secretion of extracellular enzymes and the expression of the type III secretion system,and thus affecting bacterial virulence. In the review,we summarized progresses on the c-di-GMP-related studies and discuss prospects of c-di-GMP in regulation of bacterial virulence.