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【目的】旨在揭示水稻白叶枯病菌(Xanthomonas oryzae pv.oryzae,简称Xoo)环鸟苷二磷酸(c-di-GMP)信号蛋白VieAxoo的生物学功能。【方法】本研究通过标记置换法对vieAxoo基因(PXO_04753)进行了缺失突变研究,采用表型测定进行了功能鉴定。【结果】从野生型菌株PXO99A中克隆的vieAxoo基因序列与其它病原黄单胞菌的同源序列高度保守。VieAxoo具有参与c-di-GMP降解的磷酸二酯酶(PDE)EAL结构域和磷酸信号识别受体REC结构域。与PXO99A相比,△vieAxoo基因缺失突变体对水稻的致病性、胞外多糖(EPS)产生和运动性无明显改变;但对烟草的致敏性和生物膜形成显著降低;基因互补可以使之完全恢复。【结论】VieAxoo正向调控了Xoo对烟草的致敏性和生物膜形成能力。
【Objective】 The objective of this study was to reveal the biological function of Xylhomonas oryzae pv. Oryzae (Xoo) cyclic carbonyl-dipeptide phosphate (VipAxoo). 【Method】 In this study, the deletion mutation of vieAxoo gene (PXO_04753) was studied by the marker replacement method. The phenotype assay was used for functional identification. 【Result】 The results showed that the sequence of vieAxoo cloned from wild type strain PXO99A was highly conserved among the homologous sequences of other pathogenic Xanthomonas. VieAxoo has a phosphodiesterase (PDE) EAL domain and a phosphate signal recognition receptor REC domain involved in c-di-GMP degradation. Compared with PXO99A, △ vieAxoo deletion mutant had no significant effect on the pathogenicity of rice, EPS production and motility, but significantly reduced the allergenicity and biofilm formation of tobacco. The full recovery. 【Conclusion】 VieAxoo positively regulated the sensitization and biofilm formation ability of Xoo to tobacco.