Tissue-specific Ubiquitination by IPA1 INTERACTING PROTEIN 1 Modulates IPA1 Protein Levels to Regulate Plant Architecture in Rice
    作者: Jing Wang, Hong Yu, Guosheng Xiong, Zefu Lu, Yongqing Jiao, Xiangbing Meng, Guifu Liu, Xuewei Chen, Yonghong Wang and Jiayang Li
    刊物名称: Plant Cell
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    摘要: Plant architecture, a collection of genetically controlled agronomic traits, is one of the decisive factors that determine grain production. IDEAL PLANT ARCHITECTURE 1 (IPA1) encodes a key transcription factor having pleiotropic effects on regulating plant architecture in rice (Oryza sativa), and IPA1 expression is controlled at the post-transcriptional level by microRNA156 and microRNA529. Here, we report the identification and characterization of IPA1 INTERACTING PROTEIN 1 (IPI1), a RING-finger E3 ligase that can interact with IPA1 in the nucleus. IPI1 promotes the degradation of IPA1 in panicles while it stabilizes IPA1 in shoot apexes. Consistent with these findings, the ipi1 loss-of-function mutants showed markedly altered plant architecture, including more tillers, enlarged panicles, and increased yield per plant. Moreover, IPI1 could ubiquitinate IPA1-mediated complex with different polyubiquitin chains, adding K48-linked polyubiquitin chains in panicles and K63-linked polyubiquitin chains in the shoot apex. These results demonstrate that IPI1 affects plant architecture through precisely tuning IPA1 protein levels in different tissues in rice, and provide new insight into the tissue-specific regulation of plant architecture and important genetic resources for molecular breeding applications.