An H-NS-like protein involved in the negative regulation of hrp genes in Xanthomonas oryzae pv. oryzae

作者：Kametani Ikawa Yumi; Tsuge Seiji^*; Furutani Ayako; Ochiai Hirokazu

来源：FEMS Microbiology Letters, 2011, 319(1): 58-64.

DOI：10.1111/j.1574-6968.2011.02266.x

• Xanthomonas oryzae pv
• oryzae
• hrp
• type III secretion system
• histone-like nucleoid-structuring protein

hrp genes encode components of a type III secretion (T3S) system and play crucial roles in the pathogenicity of the rice pathogen Xanthomonas oryzae pv. oryzae (Xoo). A histone-like nucleoid-structuring (H-NS) protein binds DNA and acts as a global transcriptional repressor. Here, we investigated the involvement of an h-ns-like gene, named xrvB, in the expression of hrp genes in Xoo. Under the hrp-inducing culture condition, the expression of a key hrp regulator HrpG increased in the XrvB mutant, followed by activation of the downstream gene expression. Also, in planta, the secretion of a T3S protein (XopR) was activated by the mutation in xrvB. Gel retardation assay indicated that XrvB has DNA-binding activity, but without a preference for the promoter region of hrpG. The results suggest that XrvB negatively regulates hrp gene expression and that an unknown factor(s) mediates the regulation of hrpG expression by XrvB.

• 出版日期2011-6