title: The Type III Effector AvrBs2 in Xanthomonas oryzae pv. oryzicola Suppresses Rice Immunity and Promotes Disease Development.
abstract: Xanthomonas oryzae pv. oryzicola, the causal agent of bacterial leaf streak, is one of the most important bacterial pathogens in rice. However, little is known about the functions of individual type III effectors in virulence and pathogenicity of X. oryzae pv. oryzicola. Here, we examined the effect of the mutations of 23 putative nontranscription activator-like effector genes on X. oryzae pv. oryzicola virulence. The avrBs2 knock-out mutant was significantly attenuated in virulence to rice. In contrast, the xopAA deletion caused enhanced virulence to a certain rice cultivar. It was also demonstrated that six putative effectors, including XopN, XopX, XopA, XopY, XopF1, and AvrBs2, caused the hypersensitive response on nonhost Nicotiana benthamiana leaves. Virulence function of AvrBs2 was further confirmed by transgenic technology. Pathogen-associated molecular pattern-triggered immune responses including the generation of reactive oxygen species and expression of pathogenesis-related genes were strongly suppressed in the AvrBs2-expressing transgenic rice lines. Although not inhibiting flg22-induced activation of mitogen-activated protein kinases, heterologous expression of AvrBs2 greatly promotes disease progression in rice caused by two important bacterial pathogens X. oryzae pvs. oryzae and oryzicola. Collectively, these results indicate that AvrBs2 is an essential virulence factor that contributes to X. oryzae pv. oryzicola virulence through inhibiting defense responses and promoting bacterial multiplication in monocot rice.
authors: Department of Plant Pathology, China Agricultural University, Beijing 100193, China; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors: Shuai
authors: S
authors: Li
authors: Department of Plant Pathology, China Agricultural University, Beijing 100193, China; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors: Yanping
authors: Y
authors: Wang
authors: Department of Plant Pathology, China Agricultural University, Beijing 100193, China; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors: Shanzhi
authors: S
authors: Wang
authors: Department of Plant Pathology, China Agricultural University, Beijing 100193, China; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors: Anfei
authors: A
authors: Fang
authors: Department of Plant Pathology, China Agricultural University, Beijing 100193, China; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors: Jiyang
authors: J
authors: Wang
authors: Department of Plant Pathology, China Agricultural University, Beijing 100193, China; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors: Lijuan
authors: L
authors: Liu
authors: Department of Plant Pathology, China Agricultural University, Beijing 100193, China; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors: Kang
authors: K
authors: Zhang
authors: Department of Plant Pathology, China Agricultural University, Beijing 100193, China; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors: Yuling
authors: Y
authors: Mao
authors: Department of Plant Pathology, China Agricultural University, Beijing 100193, China; Key Laboratory of Plant Pathology, Ministry of Agriculture, China Agricultural University, Beijing 100193, China.
authors: Wenxian
authors: W
authors: Sun
mesh_terms: D017360:Arabidopsis / Q000382:microbiology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D054884:Host-Pathogen Interactions / Q000276:immunology*; D009154:Mutation; D012275:Oryza / Q000276:immunology* / Q000382:microbiology*; D010935:Plant Diseases / Q000382:microbiology; D018515:Plant Leaves / Q000382:microbiology; D014026:Nicotiana / Q000382:microbiology; D014974:Xanthomonas / Q000235:genetics* / Q000472:pathogenicity*
chemical_list: D001426:Bacterial Proteins