The Role of a Host-Induced Arginase of pv. in Promoting Virulence on Rice.

The plant bacterial pathogen pv. causes bacterial blight of rice, which is one of the most destructive rice diseases prevalent in Asia and parts of Africa. Despite many years of research, how pv. causes bacterial blight of rice is still not completely understood. Here, we show that the loss of the gene caused a significant decrease in the virulence of pv. in the susceptible rice cultivar IR24. Bioinformatics analysis demonstrated that encodes arginase. Quantitative real-time PCR and Western blot assays revealed that expression was significantly induced by rice and arginine. The deletion mutant strain showed elevated sensitivity to hydrogen peroxide, reduced extracellular polysaccharide (EPS) production, and reduced biofilm formation, all of which are important determinants for the full virulence of pv. , compared with the wild-type strain. Taken together, the results of this study revealed a mechanism by which a bacterial arginase is required for the full virulence of pv. on rice because of its contribution to tolerance to reactive oxygen species, EPS production, and biofilm formation.