title: The U-Box/ARM E3 ligase PUB13 regulates cell death, defense, and flowering time in Arabidopsis.
abstract: The components in plant signal transduction pathways are intertwined and affect each other to coordinate plant growth, development, and defenses to stresses. The role of ubiquitination in connecting these pathways, particularly plant innate immunity and flowering, is largely unknown. Here, we report the dual roles for the Arabidopsis (Arabidopsis thaliana) Plant U-box protein13 (PUB13) in defense and flowering time control. In vitro ubiquitination assays indicated that PUB13 is an active E3 ubiquitin ligase and that the intact U-box domain is required for the E3 ligase activity. Disruption of the PUB13 gene by T-DNA insertion results in spontaneous cell death, the accumulation of hydrogen peroxide and salicylic acid (SA), and elevated resistance to biotrophic pathogens but increased susceptibility to necrotrophic pathogens. The cell death, hydrogen peroxide accumulation, and resistance to necrotrophic pathogens in pub13 are enhanced when plants are pretreated with high humidity. Importantly, pub13 also shows early flowering under middle- and long-day conditions, in which the expression of SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 and FLOWERING LOCUS T is induced while FLOWERING LOCUS C expression is suppressed. Finally, we found that two components involved in the SA-mediated signaling pathway, SID2 and PAD4, are required for the defense and flowering-time phenotypes caused by the loss of function of PUB13. Taken together, our data demonstrate that PUB13 acts as an important node connecting SA-dependent defense signaling and flowering time regulation in Arabidopsis.
authors.affiliation: Hunan Provincial Key Laboratory of Crop Germplasm Innovation and Utilization and Hunan Provincial Key Laboratory of Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha, Hunan 410128, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Li
authors.forename: Il-Pyung
authors.initials: IP
authors.lastname: Ahn
authors.forename: Yuese
authors.initials: Y
authors.lastname: Ning
authors.forename: Chan-Ho
authors.initials: CH
authors.lastname: Park
authors.forename: Lirong
authors.initials: L
authors.lastname: Zeng
authors.forename: Justin G A
authors.initials: JG
authors.lastname: Whitehill
authors.forename: Haibin
authors.initials: H
authors.lastname: Lu
authors.forename: Qingzhen
authors.initials: Q
authors.lastname: Zhao
authors.forename: Bo
authors.initials: B
authors.lastname: Ding
authors.forename: Qi
authors.initials: Q
authors.lastname: Xie
authors.forename: Jian-Min
authors.initials: JM
authors.lastname: Zhou
authors.forename: Liangying
authors.initials: L
authors.lastname: Dai
authors.forename: Guo-Liang
authors.initials: GL
authors.lastname: Wang
mesh_terms: D017360:Arabidopsis / Q000201:enzymology / Q000235:genetics / Q000382:microbiology / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D020171:Botrytis / Q000276:immunology / Q000472:pathogenicity; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism; D016923:Cell Death; D003001:Cloning, Molecular; D004789:Enzyme Activation; D057075:Enzyme Assays; D035264:Flowers / Q000378:metabolism / Q000502:physiology*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006813:Humidity; D006861:Hydrogen Peroxide / Q000378:metabolism; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism; D010935:Plant Diseases / Q000276:immunology / Q000382:microbiology; D057865:Plant Immunity; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics / Q000382:microbiology / Q000502:physiology; D017434:Protein Structure, Tertiary; D011549:Pseudomonas / Q000472:pathogenicity; D012459:Salicylates / Q000378:metabolism; D013997:Time Factors; D044767:Ubiquitin-Protein Ligases / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: C419046:AGL20 protein, Arabidopsis; D029681:Arabidopsis Proteins; C418902:At5g10140 protein, Arabidopsis; D026161:MADS Domain Proteins; D012459:Salicylates; D006861:Hydrogen Peroxide; C558942:PUB13 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases; D002265:Carboxylic Ester Hydrolases; C400766:PAD4 protein, Arabidopsis