COPII Components Sar1b and Sar1c Play Distinct Yet Interchangeable Roles in Pollen Development1[OPEN]
COPII Components Sar1b and Sar1c Play Distinct Yet Interchangeable Roles in Pollen Development1[OPEN]
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COPII 成分 Sar1b 和 Sar1c 在花粉发育中发挥不同但可互换的作用
DOI：
10.1104/pp.20.00159
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发表时间：
2020-07-01
期刊：
影响因子：
7.4
通讯作者：
Zhang, Yan
中科院分区：
文献类型：
--
作者：
Liang, Xin;Li, Shan-Wei;Zhang, Yan
小的GTSAr 1是COPII复合物的一个组成部分，它介导囊泡从内质网运输到高尔基体，参与拟南芥花粉发育的孢子体和配子体控制，不同的亚型发挥不同或冗余的作用。外壳蛋白复合物II（COPII）介导囊泡从内质网到高尔基体的顺行运输。已报道COPII复合物的组分调节花粉发育的孢子体或配子体控制。拟南芥（Arabidopsis thaliana）基因组编码5种Sar 1亚型，这是COPII形成所必需的小GTP酶。通过使用显性阴性方法，提出了Sar 1亚型具有不同的货物特异性，尽管它们的序列相似性。在这里，我们通过分析转移DNA插入突变体和CRISPR/Cas9产生的突变体来检查三种Sar 1亚型的功能。我们报告的功能丧失Sar 1b引起绒毡层功能障碍，导致雄性不育。Sar 1c的异位表达可以弥补Sar 1b在孢子体控制花粉发育中的功能缺失，表明它们是可互换的。基于表达分析，Sar 1b和Sar 1c之间的功能差异可能是由于它们不同的基因转录水平。另一方面，Sar 1b和Sar 1c冗余地介导雄配子体发育，使得thesar 1b; sar 1c小孢子在花药发育阶段10败育。这项研究揭示了Sar 1亚型在孢子体和配子体控制花粉发育中的作用。这也表明，不同的功能的Sar 1亚型可能是由其不同的转录程序。
The small GTPase Sar1, a component of the COPII complex that mediates vesicular trafficking from ER to Golgi, participates in sporophytic and gametophytic control of pollen development in Arabidopsis, with different isoforms playing distinct or redundant roles.The development of pollen is a prerequisite for double fertilization in angiosperms. Coat protein complex II (COPII) mediates anterograde transport of vesicles from the endoplasmic reticulum to the Golgi. Components of the COPII complex have been reported to regulate either sporophytic or gametophytic control of pollen development. The Arabidopsis (Arabidopsis thaliana) genome encodes five Sar1 isoforms, the small GTPases essential for COPII formation. By using a dominant negative approach, Sar1 isoforms were proposed to have distinct cargo specificity despite their sequence similarity. Here, we examined the functions of three Sar1 isoforms through analysis of transfer DNA insertion mutants and CRISPR/Cas9-generated mutants. We report that functional loss ofSar1bcaused malfunction of tapetum, leading to male sterility. Ectopic expression ofSar1ccould compensate forSar1bloss of function in sporophytic control of pollen development, suggesting that they are interchangeable. Functional distinction between Sar1b and Sar1c may have resulted from their different gene transcription levels based on expression analyses. On the other hand, Sar1b and Sar1c redundantly mediate male gametophytic development such that thesar1b;sar1cmicrospores aborted at anther developmental stage 10. This study uncovers the role of Sar1 isoforms in both sporophytic and gametophytic control of pollen development. It also suggests that distinct functions of Sar1 isoforms may be caused by their distinct transcription programs.