Chloroplast-targeted Hsp90 plays essential roles in plastid development and embryogenesis in Arabidopsis possibly linking with VIPP1
Chloroplast-targeted Hsp90 plays essential roles in plastid development and embryogenesis in Arabidopsis possibly linking with VIPP1
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叶绿体靶向的 Hsp90 在拟南芥质体发育和胚胎发生中发挥重要作用，可能与 VIPP1 相关。
DOI：
10.1111/ppl.12083
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发表时间：
2014-02-01
影响因子：
6.4
通讯作者：
Li, Yinxin
中科院分区：
文献类型：
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作者：
Feng, Juanjuan;Fan, Pengxiang;Li, Yinxin
拟南芥基因组包含7个Hsp 90成员。质体AtHsp90.5突变导致叶绿体发育和胚胎发生缺陷。然而，质体AtHsp90.5的确切功能尚未确定。在本研究中，在AtHsp 90. 5转化的拟南芥中发现了白化病幼苗，这表明它们是AtHsp 90. 5共抑制的植物。白化植株光合超复合物的积累减少，光合作用相关基因的表达显著下调。AtHsp 90. 5 T-DNA插入突变体是胚胎致死的，胚胎停滞在心脏期。进一步的研究表明，AtHsp90.5在开花后4天（DPA）的角果中表达上调。共聚焦显微镜证实AtHsp90.5定位于叶绿体中。AtHsp90.5突变体和共抑制植物中的质体发育严重受损，观察到很少的类囊体膜，表明AtHsp90.5参与叶绿体生物合成。利用双分子荧光互补系统发现AtHsp90.5与质体中的小泡诱导蛋白VIPP 1相互作用。AtHsp90.5共抑制植物中VIPP 1寡聚体和单体之间的比例急剧向寡聚体状态转变。我们的研究证实了AtHsp90.5在叶绿体生物发生和胚胎发生中的重要作用。进一步的证据还表明，AtHsp90.5可能有助于VIPP 1的分解，以形成和/或维持类囊体膜。
The Arabidopsis genome contains seven members of Hsp90. Mutations in plastid AtHsp90.5 were reported to cause defects in chloroplast development and embryogenesis. However, the exact function of plastid AtHsp90.5 has not yet been defined. In this study, albino seedlings were found among AtHsp90.5 transformed Arabidopsis, which were revealed to be AtHsp90.5 co-suppressed plants. The accumulation of photosynthetic super-complexes in the albinos was decreased, and expression of genes involved in photosynthesis was significantly down-regulated. AtHsp90.5 T-DNA insertion mutants were embryo-lethal with embryo arrested at the heart stage. Further investigation showed AtHsp90.5 expression was up-regulated in the siliques at 4 days post anthesis (DPA). Confocal microscopy proved AtHsp90.5 was located in the chloroplasts. Plastid development in the AtHsp90.5 mutants and co-suppressed plants was seriously impaired, and few thylakoid membranes were observed, indicating the involvement of AtHsp90.5 in chloroplast biogenesis. AtHsp90.5 was found to interact with vesicle-inducing protein in plastids 1 (VIPP1) by bimolecular fluorescence complementation system. The ratio between VIPP1 oligomers and monomers in AtHsp90.5 co-suppressed plants drastically shifted toward the oligomeric state. Our study confirmed that AtHsp90.5 is vital for chloroplast biogenesis and embryogenesis. Further evidence also suggested that AtHsp90.5 may help in the disassembly of VIPP1 for thylakoid membrane formation and/or maintenance.