Overexpression of a Functional Vicia sativa PCS1 Homolog Increases Cadmium Tolerance and Phytochelatins Synthesis in Arabidopsis.
Overexpression of a Functional Vicia sativa PCS1 Homolog Increases Cadmium Tolerance and Phytochelatins Synthesis in Arabidopsis.
复制标题
功能性蚕豆 PCS1 同源物的过度表达增加拟南芥的镉耐受性和植物螯合素合成
DOI：
10.3389/fpls.2018.00107
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发表时间：
2018
影响因子：
5.6
通讯作者：
Shen Z
中科院分区：
文献类型：
--
作者：
Zhang X;Rui H;Zhang F;Hu Z;Xia Y;Shen Z
植物螯合素酶（PCS）催化的植物螯合素（PC）在植物和其他生物体的金属解毒中起着重要作用。本研究从箭舌豌豆（Vicia sativa）中克隆了一个PCS基因（VsPCS 1），并研究了其在镉（Cd）耐性调控中的作用。镉胁迫下，紫花苜蓿根中VsPCS 1的表达被诱导。亚细胞定位分析表明，VsPCS 1定位于紫花苜蓿叶肉原生质体的细胞质中。在拟南芥中过量表达VsPCS 1（35 S：：VsPCS 1，在野生型背景下）可以弥补AtPCS 1缺陷突变体（atpcs 1）的镉耐受缺陷。与atpcs 1突变体相比，35 S：：VsPCS 1/atpcs 1（AtPCS 1缺失突变体背景）转基因植株叶肉细胞质中Cd荧光强度显著降低，同时液泡中Cd荧光强度增强，表明转基因植株对Cd的耐受性增强可能是由于其将更多的Cd固定到液泡中。此外，过量表达VsPCS 1可提高35 S：：VsPCS 1对Cd的耐性，但对Cd的积累和分配没有影响，表现出与野生型（WT）相同的Cd荧光强度。进一步分析表明，这种增加的耐受性在35 S：：VsPCS 1可能是由于增加的PCs螯合镉在胞质溶胶中。两者合计，从V. sativa中鉴定出功能性PCS 1同源物，其对将Cd保留在胞质溶胶而不是液泡中的高阶PC的合成具有强催化性质。这些发现丰富了PCS介导的高等植物镉解毒的原始模型。
Phytochelatins (PCs) catalyzed by phytochelatin synthases (PCS) are important for the detoxification of metals in plants and other living organisms. In this study, we isolated a PCS gene (VsPCS1) from Vicia sativa and investigated its role in regulating cadmium (Cd) tolerance. Expression of VsPCS1 was induced in roots of V. sativa under Cd stress. Analysis of subcellular localization showed that VsPCS1 was localized in the cytoplasm of mesophyll protoplasts of V. sativa. Overexpression of VsPCS1 (35S::VsPCS1, in wild-type background) in Arabidopsis thaliana could complement the defects of Cd tolerance of AtPCS1-deficent mutant (atpcs1). Compared with atpcs1 mutants, 35S::VsPCS1/atpcs1 (in AtPCS1-deficent mutant background) transgenic plants significantly lowered Cd-fluorescence intensity in mesophyll cytoplasm, accompanied with enhanced Cd-fluorescence intensity in the vacuoles, demonstrating that the increased Cd tolerance may be attributed to the increased PC-based sequestration of Cd into the vacuole. Furthermore, overexpressing VsPCS1 could enhance the Cd tolerance in 35S::VsPCS1, but have no effect on Cd accumulation and distribution, showing the same level of Cd-fluorescence intensity between 35S::VsPCS1 and wild-type (WT) plants. Further analysis indicated this increased tolerance in 35S::VsPCS1 was possibly due to the increased PCs-chelated Cd in cytosol. Taken together, a functional PCS1 homolog from V. sativa was identified, which hold a strong catalyzed property for the synthesis of high-order PCs that retained Cd in the cytosol rather the vacuole. These findings enrich the original model of Cd detoxification mediated by PCS in higher plants.