💡这项突破是什么?
南湖新闻网讯（通讯员 姜澳生）6月16日，我校资源与环境学院植物营养生物学课题组研究成果“Disruption of BnPHT5;1b gene enhances arsenate tolerance through increased arsenate retention in shoot cell walls of Brassica napus”在Journal of Hazardous Materials在线发表。该研究是课题组继2022年在Plant, Cell & Environment发表“Identification of vacuolar phosphate influx transporters in Brassica napus”后，围绕甘蓝型油菜液泡磷转运蛋白功能开展的进一步延伸研究。
图文摘要
砷污染是影响农产品安全和农业生态环境的重要问题。砷酸盐 [As(V)] 与磷酸盐化学性质相似，可通过植物磷转运相关途径进入细胞，进而干扰磷代谢、诱导氧化胁迫并抑制作物生长。甘蓝型油菜是我国重要油料作物，阐明其砷吸收、转运和解毒机制，对砷污染农田安全利用和作物遗传改良具有重要意义。前期研究中，课题组鉴定了甘蓝型油菜液泡磷内流转运蛋白 BnPHT5;1b，明确其定位于液泡膜并参与细胞磷稳态调控。在此基础上，本研究进一步探究 BnPHT5;1b 在砷酸盐胁迫响应及砷分配调控中的作用。研究人员系统比较了 BnPHT5;1b 突变体在砷酸盐胁迫下的生长表现、砷积累特征及分子响应。结果表明，BnPHT5;1b 突变体表现出更强的砷酸盐耐受性，具有较高生物量、较长根系和较高叶绿素含量。进一步分析发现，BnPHT5;1b 突变并未降低砷吸收，反而促进砷由根向地上部转运，并显著增加地上部砷积累。值得关注的是，虽然 BnPHT5;1b 突变体地上部砷积累增加，但籽粒砷含量并未升高。研究发现，转运至地上部的砷更多滞留于茎叶细胞壁组分中，同时突变体表现出更强的抗氧化和谷胱甘肽相关解毒响应，表明 BnPHT5;1b 突变可能通过促进砷向地上部转运、增强茎叶细胞壁砷滞留和提高细胞解毒能力，缓解砷对植株生长的毒害作用。
该研究揭示了液泡磷转运蛋白 BnPHT5;1b 在油菜砷胁迫耐受和砷分配调控中的新功能，将课题组前期关于液泡磷稳态的研究拓展至砷污染胁迫与作物安全生产领域，为油菜应用于砷污染农田植物修复和安全生产提供了新的遗传资源和理论依据。
我校资源与环境学院已毕业博士生韩贝为论文第一作者，石磊教授为通讯作者。已毕业硕士生姜澳生、湘湖实验室副研究员严军军、已毕业博士生吴涛、张兵兵、王雅洁、杨鑫宇，以及资源与环境学院汪社亮副教授、赵竹青教授等参与了研究。该研究得到国家重点研发计划项目资助。
论文链接：https://doi.org/10.1016/j.jhazmat.2026.142729
英文摘要：Arsenic (As) contamination poses a significant threat to crop production and food safety. In plants, arsenate [As(V)] is taken up into cells through phosphate transporters due to their chemical similarity, where it disrupts metabolic processes and causes oxidative stress. However, the precise role of phosphate transporters in As accumulation and tolerance remains unclear. Here, we investigated the function of BnPHT5;1b, a vacuolar phosphate influx transporter in Brassica napus. Double mutants of two BnPHT5;1b genes, BnA09.PHT5;1b and BnCn.PHT5;1b (hereafter referred to as BnPHT5;1b DM) exhibited enhanced tolerance to As(V) at the seedling stage, showing increased biomass, longer roots, and higher chlorophyll content under As stress. Transcriptome analysis revealed that both wild-type and mutant plants activated oxidative stress responses, but the BnPHT5;1b DM displayed stronger enrichment of antioxidant and detoxification pathways. Importantly, disruption of BnPHT5;1bs promoted root-to-shoot As translocation, with xylem sap As(III) and As(V) increased by 51.0% and 75.0%, respectively, and As concentrations in cotyledons, old leaves, and new leaves increased by 61.3%, 153.7%, and 129.7%, respectively. This was accompanied by 6.8-fold higher As accumulation in shoot cell walls, while seed As levels remained similar to or slightly lower than those of wild-type. These findings establish BnPHT5;1b as a key regulator of As transport and detoxification in B. napus. This study reveals a previously unrecognized strategy for enhancing arsenate tolerance while promoting root-to-shoot As translocation and shoot cell wall retention without increasing seed As accumulation, providing a potential genetic resource for phytoremediation of As-contaminated soils.
