School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China.
School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang 621010, China.
Ecotoxicol Environ Saf. 2021 Dec 15;226:112868. doi: 10.1016/j.ecoenv.2021.112868. Epub 2021 Oct 4.
With the booming demand of the electric vehicle industry, the concentration of manganese (Mn) and cobalt (Co) flowing into land ecosystems has also increased significantly. While these transition metals can promote the growth and development of plants, they may become toxic under high concentrations. It is thus important to understand how Mn and Co are distributed in plants to develop novel germplasms for the remediation of these heavy metals in contaminated soils. Here, an MTP gene that encodes the CDF (cation diffusion facilitator) protein in Populus trichocarpa, PtrMTP6, was screened as the key gene involved in the distribution of both Mn and Co in poplar. The PtrMTP6-GFP fusion protein was co-localized with the mRFP-VSR2, showing that PtrMTP6 proteins are present at the pre-vacuolar compartment (PVC). Yeast mutant complementation assays further identified that PtrMTP6 serves as a Mn and Co transporter, reducing yeast cell toxicity after exposure to excessive Mn or Co. Histochemical analyses showed that PtrMTP6 was mainly expressed in phloem, suggesting that PtrMTP6 probably involved in the Mn and Co transport via phloem in plants. Under excess Co, PtrMTP6 overexpressing poplar lines were more severely damaged than the control due to higher Co accumulations in young tissue. PtrMTP6 overexpressing lines showed little change in their tolerance to excess Mn, although young tissues also accumulated more Mn. PtrMTP6 play important roles in Mn and Co distribution in poplar and further research on its regulation will be important to increase bioremediation in Mn and Co polluted ecosystems.
随着电动汽车行业的蓬勃发展，流入陆地生态系统的锰（Mn）和钴（Co）浓度也显著增加。虽然这些过渡金属可以促进植物的生长和发育，但在高浓度下它们可能会变得有毒。因此，了解 Mn 和 Co 在植物中的分布对于开发用于修复污染土壤中这些重金属的新型种质资源非常重要。在这里，筛选出毛果杨（Populus trichocarpa）中编码 CDF（阳离子扩散促进剂）蛋白的 MTP 基因，PtrMTP6，作为 Mn 和 Co 在杨树中分布的关键基因。PtrMTP6-GFP 融合蛋白与 mRFP-VSR2 共定位，表明 PtrMTP6 蛋白存在于前液泡区（PVC）。酵母突变体互补测定进一步鉴定出 PtrMTP6 作为 Mn 和 Co 转运蛋白，在暴露于过量 Mn 或 Co 后减少酵母细胞毒性。组织化学分析表明，PtrMTP6 主要在韧皮部表达，表明 PtrMTP6 可能参与植物中 Mn 和 Co 通过韧皮部的运输。在过量 Co 存在下，由于幼组织中积累的 Co 更高，PtrMTP6 过表达的杨树品系比对照品系受到更严重的损害。PtrMTP6 过表达系在对过量 Mn 的耐受性方面变化不大，尽管幼组织也积累了更多的 Mn。PtrMTP6 在 Mn 和 Co 在杨树中的分布中发挥重要作用，进一步研究其调控机制对于增加 Mn 和 Co 污染生态系统的生物修复将非常重要。
