Expressing Phosphate Transporter PvPht2;1 Enhances P Transport to the Chloroplasts and Increases Arsenic Tolerance in Arabidopsis thaliana
Expressing Phosphate Transporter PvPht2;1 Enhances P Transport to the Chloroplasts and Increases Arsenic Tolerance in Arabidopsis thaliana
复制标题
表达磷酸盐转运蛋白 PvPht2;1 增强拟南芥叶绿体磷转运并提高砷耐受性
DOI：
10.1021/acs.est.0c03316
复制
发表时间：
2021-02-16
影响因子：
11.4
通讯作者：
Ma, Lena Q.
中科院分区：
文献类型：
--
作者：
Feng, Huayuan;Li, Xinyuan;Ma, Lena Q.
土壤中砷污染对植物的毒害作用引起了人们的广泛关注。磷作为一种类似物，在保护植物免受砷毒害方面起着重要作用。本研究从砷超富集植物蜈蚣蕨（Pteris vittata）中鉴定了一个新的磷酸盐转运蛋白2（PHT 2）PvPht 2;1，并分析了其在酵母突变体和模式植物拟南芥中的砷和磷转运功能。PvPht 2;1含有12个跨膜结构域，与植物中的PHT 2基因具有高度的同源性。PvPht 2;1主要在杜仲叶中表达，其表达量是杜仲根和根茎中的3-4倍，与外源P或As水平无关。PvPht 2; 1定位于模式植物烟草的叶绿体中，是一种低亲和力的磷转运蛋白。As暴露下，PvPht 2; 1酵母转化体显示与对照相当的生长，而高亲和力P转运蛋白PvPht 1;3转化体显示更好的生长，表明PvPht 2;1转运P，但慢于PvPht 1;3转运蛋白。PvPht 2;1在A.拟南芥提高了地上部磷浓度，但不影响砷的积累。此外，转基因A.拟南芥的生长比野生型（WT）植物增加37-59%。在砷胁迫下，表达PvPht 2;1的A. thaliana保持稳定，但WT植物的下降。结果表明，在As胁迫下，表达PvPht 2;1的A.拟南芥增强了磷向叶绿体的运输，保护了光合作用。总之，在叶片中高度表达，不受As暴露的影响，位于叶绿体的PvPht 2;1可能通过有效地将P仅运输到叶绿体来保护Ashyperaccumulator P. vittata免受As毒性。
Arsenic (As) contamination in soils is of great concerns due to its toxicity to plants. As an analogue, phosphorus plays an important role in protecting plants from As toxicity. In this study, we identified a new phosphate transporter 2 (PHT2), PvPht2;1, from As-hyperaccumulator Pteris vittata and analyzed its functions in As and P transport in a yeast mutant, and model plant Arabidopsis thalian. PvPht2;1 contained 12 transmembrane domains, sharing high identity with PHT2 genes in diverse plants. Further, independent of external P or As levels, PvPht2;1 was mainly expressed in P. vittata fronds with the expression being 3-4 folds higher than that in the roots and rhizomes. Localized to the chloroplasts based on GFP-fused PvPht2;1 in model plant tobacco, PvPht2;1 functioned as a low-affinity P transporter. Under As exposure, PvPht2;1 yeast transformants showed comparable growth with the control while high-affinity P transporter PvPht1;3 transformants showed better growth, suggesting that PvPht2;1 transported P but slower than PvPht1;3 transporter. Expressing PvPht2;1 in A. thaliana increased its shoot P concentration without influencing its As accumulation. Further, the chloroplasts' P content in transgenic A. thaliana increased by 37-59% than wild-type (WT) plants. Under As exposure, the photosynthesis of PvPht2;1-expressing A. thaliana remained stable but that of WT plants decreased. The data indicate that, under As stress, expressing PvPht2;1 in A. thaliana enhanced its P transport to the chloroplasts and protected its photosynthesis. In short, highly expressed in the fronds and not impacted by As exposure, chloroplast-located PvPht2;1 may have protected Ashyperaccumulator P. vittata from As toxicity by efficiently transporting only P to its chloroplasts.