The Plant Cell:中科院遗传所李家洋研究组发表水稻理想株型研究进
2017年3月14日，国际植物科学顶级期刊《The Plant Cell》在线发表了中国科学院遗传与发育生物学研究所李家洋研究组的一篇研究论文，研究在水稻理想株型研究取得新进展。已毕业的博士研究生王静和副研究员余泓博士为该论文的共同第一作者，李家洋研究员和王永红研究员为共同通讯作者。
水稻的株型是决定水稻产量的主要因素之一，水稻理想株型的塑造是提高水稻产量的重要途径。控制水稻理想株型的主基因IPA1 (Ideal plant Architecture 1) 编码一个含SBP-box的转录因子，参与调控多个生长发育过程。通过对IPA1的互作蛋白IPI1的系统深入研究，表明IPI1编码一个RING-finger E3 ligase，能够和IPA1在细胞核内发生互作，并泛素化IPA1蛋白;IPI1功能丧失突变体的IPA1蛋白水平在茎基部降低，但在穗部升高，相应地植株表现出分蘖数增加、穗子变大和每穗粒数增加的表型;进一步生化分析揭示，IPI1对IPA1的泛素化具有组织特异性，从而精细调控不同组织IPA1蛋白水平。该研究为进一步解析水稻株型调控遗传调控网络和水稻品种设计奠定了基础。
原文链接：
Tissue-specific Ubiquitination by IPA1 INTERACTING PROTEIN 1 Modulates IPA1 Protein Levels to Regulate Plant Architecture in RICE
原文摘要：
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.
作者：李家洋
