title: Rice XA21 binding protein 3 is a ubiquitin ligase required for full Xa21-mediated disease resistance.
abstract: XA21 is a receptor-like kinase protein in rice (Oryza sativa) that confers gene-for-gene resistance to specific races of the causal agent of bacterial blight disease, Xanthomonas oryzae pv oryzae. We identified XA21 binding protein 3 (XB3), an E3 ubiquitin ligase, as a substrate for the XA21 Ser and Thr kinase. The interaction between XB3 and the kinase domain of XA21 has been shown in yeast and in vitro, and the physical association between XB3 and XA21 in vivo has also been confirmed by coimmunoprecipitation assays. XB3 contains an ankyrin repeat domain and a RING finger motif that is sufficient for its interaction with the kinase domain of XA21 and for its E3 ubiquitin ligase activity, respectively. Transgenic plants with reduced expression of the Xb3 gene are compromised in resistance to the avirulent race of X. oryzae pv oryzae. Furthermore, reduced levels of Xb3 lead to decreased levels of the XA21 protein. These results indicate that Xb3 is necessary for full accumulation of the XA21 protein and for Xa21-mediated resistance.
authors.affiliation: Department of Plant Pathology, University of Florida, Gainesville, Florida 32611, USA.
authors.forename: Yong-Sheng
authors.initials: YS
authors.lastname: Wang
authors.forename: Li-Ya
authors.initials: LY
authors.lastname: Pi
authors.forename: Xiuhua
authors.initials: X
authors.lastname: Chen
authors.forename: Pranjib K
authors.initials: PK
authors.lastname: Chakrabarty
authors.forename: Junda
authors.initials: J
authors.lastname: Jiang
authors.forename: Alfred Lopez
authors.initials: AL
authors.lastname: De Leon
authors.forename: Guo-Zhen
authors.initials: GZ
authors.lastname: Liu
authors.forename: Liangcai
authors.initials: L
authors.lastname: Li
authors.forename: Ulla
authors.initials: U
authors.lastname: Benny
authors.forename: James
authors.initials: J
authors.lastname: Oard
authors.forename: Pamela C
authors.initials: PC
authors.lastname: Ronald
authors.forename: Wen-Yuan
authors.initials: WY
authors.lastname: Song
mesh_terms: D000595:Amino Acid Sequence; D017089:Ankyrin Repeat; D018628:Gene Dosage; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D007113:Immunity, Innate / Q000235:genetics / Q000276:immunology*; D008969:Molecular Sequence Data; D012275:Oryza / Q000201:enzymology* / Q000235:genetics; D010766:Phosphorylation; D010935:Plant Diseases / Q000235:genetics / Q000276:immunology*; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D013379:Substrate Specificity; D013816:Thermodynamics; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015003:Yeasts / Q000201:enzymology
chemical_list: D010940:Plant Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D025801:Ubiquitin; C097148:Xa21 protein, Oryza sativa; D044767:Ubiquitin-Protein Ligases; D017346:Protein Serine-Threonine Kinases