Xu Shu, Pan Xiayan, Luo Jianying, Wu Jian, Zhou Zehua, Liang Xiaoyu, He Yawen, Zhou Mingguo
College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, China; Key Laboratory of Pesticide, Nanjing Agricultural University, Jiangsu Province, China.
State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China.
Pestic Biochem Physiol. 2015 Jan;117:39-46. doi: 10.1016/j.pestbp.2014.10.006. Epub 2014 Oct 16.
Xanthomonas oryzae pv. oryzae (Xoo) is the casual agent of bacterial blight, which is one of the most serious diseases of rice. The antibiotic phenazine-1-carboxylic acid (PCA), which is primarily produced by Pseudomonas spp., was found and previously reported very effective against Xoo. However, the biological effects of PCA on Xoo remain unclear. In this study, we found that PCA increased the accumulation of reactive oxygen species (ROS) and reduced the activities of catalase (CAT) and superoxide dismutase (SOD) in Xoo. Xoo was more sensitive to H2O2 than Xanthomonas oryzae pv. oryzicola (Xoc), and had a much lower expression of CAT genes. In addition, proteomic analysis indicated that PCA inhibited carbohydrate metabolism and nutrient uptake in Xoo, and analysis of carbon source utilization further confirmed that carbohydrate metabolism in Xoo was repressed by PCA. In conclusion, PCA acted as a redox-cycling agent that disturbed the redox balance in Xoo and reduced CAT and SOD activities, resulting in higher accumulation of ROS, altered carbohydrate metabolism, and lower energy production and nutrient uptake. Moreover, a deficient antioxidant system in Xoo made it very sensitive to PCA.
水稻白叶枯病菌（Xanthomonas oryzae pv. oryzae，简称Xoo）是导致水稻白叶枯病的病原菌，水稻白叶枯病是水稻最严重的病害之一。抗生素吩嗪-1-羧酸（PCA）主要由假单胞菌属产生，已被发现且先前报道其对Xoo非常有效。然而，PCA对Xoo的生物学效应仍不清楚。在本研究中，我们发现PCA增加了Xoo中活性氧（ROS）的积累，并降低了过氧化氢酶（CAT）和超氧化物歧化酶（SOD）的活性。与水稻条斑病菌（Xanthomonas oryzae pv. oryzicola，简称Xoc）相比，Xoo对H2O2更敏感，且其CAT基因的表达水平低得多。此外，蛋白质组学分析表明PCA抑制了Xoo中的碳水化合物代谢和营养吸收，碳源利用分析进一步证实PCA抑制了Xoo中的碳水化合物代谢。总之，PCA作为一种氧化还原循环剂，扰乱了Xoo中的氧化还原平衡，降低了CAT和SOD的活性，导致ROS积累增加、碳水化合物代谢改变以及能量产生和营养吸收减少。此外，Xoo中抗氧化系统的缺陷使其对PCA非常敏感。
