Plant Journal：中科院遗传发育所陈凡研究组揭示MAPK信号通路参与

摘要 : 9月14日The Plant Journal在线发表中国科学院遗传与发育生物学研究所陈凡研究组、李云海研究组与中国水稻所合作发表的关于MAPK信号通路调控水稻种子大小机制文章。

9月14日The plant Journal在线发表中国科学院遗传与发育生物学研究所陈凡研究组、李云海研究组与中国水稻所合作发表的关于MAPK信号通路调控水稻种子大小机制文章。陈凡研究组的博士研究生刘书英为该论文的第一作者，副研究员方晓华和研究员陈凡为共同通讯作者。

种子大小是决定水稻产量的重要因素之一，其调控机制备受关注。丝裂原活化蛋白激酶MAPKs是生物体中广泛存在的蛋白激酶，它们在植物生长发育以及胁迫反应过程中发挥了重要作用，然而关于MAPK信号通路参与种子大小调控的作用机制并不清楚。

中国科学院遗传与发育生物学研究所陈凡研究组、李云海研究组与中国水稻所合作鉴定了一个水稻矮杆小粒突变体(dwarf and small grain1, dsg1)。图位克隆结果表明DSG1编码一个丝裂原活化蛋白激酶OsMAPK6，与拟南芥中类似，它处于OsMKK4的下游发挥作用。细胞生物学分析表明DSG1是通过调控细胞分裂而调节了细胞数目，进而影响了水稻种子大小及其生物量。进一步的生理学和分子生物学实验分析表明DSG1调控种子大小与油菜素内酯相关。该研究为进一步解析种子大小的遗传调控机制以及改良水稻品质与产量奠定了良好的基础。


水稻矮杆小粒突变体(dwarf and small grain1, dsg1)的表型分析

原文链接：

OsMAPK6, a mitogen-activated protein kinase, influences rICE grain size and biomass production

原文摘要：

Grain size is an important agronomic trait in determining grain yield. However, the molecular mechanisms that determine the final grain size is not well understood. Here, we report the functional analysis of a rice (Oryza sativa L.) mutant, dwarf and small grains1 (dsg1), which displays pleiotropic phenotypes, including small grains, dwarfism and erect leaves. Cytological observations revealed that the small grain and dwarfism of dsg1 were mainly caused by the inhibition of cell proliferation. Map-based cloning revealed that DSG1 encoded a mitogen-activated protein kinase (MAPK), OsMAPK6. OsMAPK6 mainly located in the nucleus and cytoplasm, and was ubiquitously distributed in various organs, predominately in spikelets and spikelet hulls, consistent with its role in grain size and biomass production. As a functional kinase, OsMAPK6 interacts strongly with OsMKK4, indicating that OsMKK4 is likely to be the upstream MAPKK of OsMAPK6 in rice. In addition, hormone sensitivity tests indicated that the dsg1 mutant was less sensitive to brassinosteroids (BRs). The endogenous BR levels were reduced in dsg1, and the expression of several BR signaling pathway genes and feedback-inhibited genes were altered in the dsg1 mutant, with or without exogenous BRs, indicating that OsMAPK6 may contribute to influence BR homeostasis and signaling. Thus, OsMAPK6, a mitogen-activated protein kinase, plays a pivotal role in grain size, via cell proliferation, and BR signaling and homeostasis, in rice.

DOI: 10.1111/tpj.13025

作者：陈凡

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