Yan Xiaoyuan, Yan Zongyun, Han Yuzhen
State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural UniversityBeijing, China.
Front Plant Sci. 2017 Jun 8;8:981. doi: 10.3389/fpls.2017.00981. eCollection 2017.
The exosome complex plays a central and essential role in RNA metabolism. However, current research on functions of exosome subunit in plants is limited. Here, we used an egg cell-specific promoter-controlled CRISPR/Cas9 system to knock out which encodes a core subunit of the exosome and presented evidence that RRP42 is essential for the development of female gametophytes. Next, we designed three different amiRNAs targeting . The knock-down mutants mainly displayed variegated and serrated leaves, especially in cauline leaves. The internal anatomy of cauline leaves displayed irregularly shaped palisade cells and a reduced density of mesophyll cells. Interestingly, we detected highly accumulated mRNAs that encode xyloglucan endotransglucosylase/hydrolases (XTHs) and expansins (EXPAs) during later growth stages in knock-down mutants. The mRNA decay kinetics analysis for , , and revealed that RRP42 had a role in the decay of these mRNAs in the cytoplasm. RRP42 is localized to both the nucleus and cytoplasm, and is preferentially expressed in cauline leaves during later growth stages. Altogether, our results demonstrate that RRP42 is essential for the development of female gametophytes and plays an important role in mesophyll cell morphogenesis.
外泌体复合物在RNA代谢中发挥着核心且至关重要的作用。然而，目前关于植物中外泌体亚基功能的研究有限。在此，我们使用卵细胞特异性启动子控制的CRISPR/Cas9系统敲除了编码外泌体核心亚基的RRP42，并提供证据表明RRP42对雌配子体的发育至关重要。接下来，我们设计了三种靶向RRP42的不同amiRNA。RRP42敲低突变体主要表现出叶片杂色和锯齿状，尤其是在茎生叶中。茎生叶的内部解剖结构显示出栅栏细胞形状不规则且叶肉细胞密度降低。有趣的是，我们在RRP42敲低突变体的后期生长阶段检测到编码木葡聚糖内转糖基酶/水解酶（XTHs）和扩展蛋白（EXPAs）的mRNA高度积累。对RRP42、XTHs和EXPAs的mRNA衰变动力学分析表明，RRP42在细胞质中这些mRNA的衰变中起作用。RRP42定位于细胞核和细胞质，且在后期生长阶段在茎生叶中优先表达。总之，我们的结果表明RRP42对雌配子体的发育至关重要，并在叶肉细胞形态发生中起重要作用。
