MutL调控水稻黄单胞菌的致病力

为了了解水稻白叶枯病菌(Xanthomonas oryzae pv. oryzae，Xoo)中 的MutL/MutS系统是否参与DNA修复以及是否调控病原菌的致病力，构建了mutL突变体，比较了野生型与mutL突变体的突变率差异，野生型、mutL突变体及其互补菌株侵染水稻的能力。结果显示，mutL突变导致Xoo在H₂O₂胁迫下的突变率显著升高，mutL突变导致Xoo致病力下降，表明DNA错配修复蛋白MutL参与Xoo的DNA修复并正调控Xoo致病力。

MutL is required for virulence of Xanthomonas oryzae pv. oryzae

Environmental stimulus and DNA replication may cause DNA mismatch and thus genomic instability, which must be repaired by organisms. All organisms evolve DNA repair systems to cope with these damages. MutL/MutS is the key DNA repair system of bacteria, but its function remains unknown in Xanthomonas oryzae pv. oryzae (Xoo). Whether MutL/MutS is involved in DNA repair and virulence in Xoo needs further studies. MutL mutant and its complementary strain were constructed, and their virulence and mutation rates were analyzed. Results showed that MutL mutation increased Xoo mutation rates under H₂O₂ stress, indicating that MutL is important for DNA repair during the stress. It was also found that MutL mutation reduced Xoo infection ability in rice leaves, suggesting that MutL is required for Xoo-rice interaction. In summary, MutL is involved in DNA repair in Xoo, and is also vital for Xoo virulence.