Plant Physiology∣SEIPIN蛋白介導脂滴生物合成以促進花粉傳播並降低種子休眠

02-01

本論文於2017年12月4日在線發表於Plant Physiology，原文題目如下：

SEIPIN proteins mediate lipid droplet biogenesis to promote pollen transmission and reduce seed dormancy

摘要：

脂滴是植物細胞中普遍存在的細胞器，但其生理作用大部分是未知的。為了深入了解脂滴在植物中的功能，我們已經表徵了SEIPIN蛋白的擬南芥同源物，其是酵母和動物中脂滴生物合成的關鍵因子。SEIPIN1幾乎只在胚胎中表達，而SEIPIN2和SEIPIN3在胚胎和花粉中具有最大水平的表達譜，也是脂滴積累最豐富的位置。遺傳分析表明，所有三個SEIPINs有助於脂滴在胚胎中正確的生物發生，而在花粉中，只有SEIPIN2和SEIPIN3發揮重要作用。雙突變體seipin2 seipin3和seipin三突變體在種子和花粉中累積極度增大的脂滴，這阻礙了它們隨後在萌發過程中的動員。有趣的是，電子顯微鏡分析揭示了在seipin三突變體胚胎中，存在附著於I型核質網的核脂滴，這支持了SEIPINs對於維持在核膜上脂滴出芽的正確極性，將其限制在外膜上是必需的。在花粉中，脂滴生物合成和周轉的擾動與體外發芽減少以及體內受精效率較低有關。在種子中，seipin2seipin3和seipin三突變體中的發芽本身不受影響，但是種子休眠水平顯著增加。我們的研究結果揭示了SEIPIN依賴的脂滴生物合成在花粉傳播和調整種子萌發時間的相關性，是農業中兩個重要的適應性特徵

Abstract：

Lipid droplets (LDs) are ubiquitous organelles in plant cells, but their physiological roles are largely unknown. To gain insight into the function of LDs in plants, we have characterized the Arabidopsis homologues of SEIPIN proteins, which are crucial factors for LD biogenesis in yeast and animals. SEIPIN1 is expressed almost exclusively in embryos, while SEIPIN2 and SEIPIN3 have broader expression profiles with maximal levels in embryos and pollen, where LDs accumulate most abundantly. Genetic analysis demonstrates that all three SEIPINs contribute to proper LD biogenesis in embryos, whereas in pollen, only SEIPIN2 and SEIPIN3 play a significant role. The double seipin2 seipin3 and triple seipin mutants accumulate extremely enlarged LDs in seeds and pollen, which hinders their subsequent mobilization during germination. Interestingly, electron microscopy analysis reveals the presence of nuclear LDs attached to type I nucleoplasmic reticulum in triple seipin mutant embryos, supporting that SEIPINs are essential for maintaining the correct polarity of LD budding at the nuclear envelope, restricting it to the outer membrane. In pollen, the perturbations in LD biogenesis and turnover are coupled to reduced germination in vitro and with lower fertilization efficiency in vivo. In seeds, germination per se is not affected in seipin2 seipin3 and triple seipin mutants but there is a striking increase in seed dormancy levels. Our findings reveal the relevance of SEIPIN-dependent LD biogenesis in pollen transmission and in adjusting the timing of seed germination, two key adaptive traits of great importance in agriculture

每日一詞
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美[?h?nd?]
vt. 阻礙，妨礙; 成為阻礙;
adj. 後面的，後方的;

[例句]Does the fact that your players are part-timers help or hinder you?
隊員們都是兼職的，這對你有利還是不利？

[其他] 第三人稱單數：hinders 現在分詞：hindering 過去式：hindered 過去分詞：hindered