南湖新闻网讯（通讯员 朱凯杰）近日，果蔬园艺作物种质创新与利用全国重点实验室桃树栽培生理与生态课题组在桃树应答锰过量胁迫方面取得新进展，研究成果以“Insights Into the Mechanisms of Tonoplast Dicarboxylate Transporter‐Induced Plant Tolerance Against Manganese Toxicity in Peach”为题在Plant, Cell & Environment发表。

桃原产于我国，在世界范围内广泛栽培。在我国的种植面积超过1500万亩，年产量高达1800多万吨，是第四大类经济果树。近年来，随着传统农业措施的缺失和化肥过量的施用，土壤酸化问题日益严重，导致土壤中游离态锰等重金属离子的过量释放，严重影响作物生长及产量品质。

课题组前期产业调研，发现鄂南棕红壤桃树枝枯叶黄和果实品质差，元素检测显示桃园土壤和枝条中锰含量过高。为此，课题组系统解析了锰过量对桃苗生长及代谢的影响，研究结果不仅丰富了多年生果树锰耐受的理论认知，还为产业实践提供了切实可行的解决方案。

PpTDT介导苹果酸转运缓解桃锰胁迫的分子机制

研究通过生理生化及转录组分析，发现锰过量显著诱导桃苗中有机酸的积累，特别是苹果酸。外源施加苹果酸显著缓解桃苗对锰过量胁迫的敏感反应。进一步研究发现，液泡膜二羧酸转运蛋白‌PpTDT‌基因的表达受锰和苹果酸双重诱导表达。在烟草、桃叶片及根系中过表达PpTDT增加了苹果酸含量，提高桃苗对锰过量胁迫的抗性。反之，桃苗中沉默PpTDT降低苹果酸含量，加剧了桃苗的锰毒害症状。综上，PpTDT通过调控苹果酸向液泡转运，将锰离子“锁进”细胞“垃圾处理站”，从而增强桃苗对锰过量胁迫的抗性‌。

研究不仅揭示了桃响应锰过量胁迫的分子机理，还提出‌苹果酸‌作为天然化合物缓解桃及其他多年生果树锰过量胁迫中的潜力，为园艺作物重金属抗性遗传改良提供了理论依据。

华中农业大学园艺林学学院朱凯杰副研究员为论文第一作者，刘军伟教授为论文通讯作者。华中农业大学王创教授、李国怀教授及孟加拉国锡尔赫特农业大学Mirza Hasanuzzaman教授参与指导了本研究工作。该研究得到了国家自然科学基金（32272645和32402479）和国家现代桃产业技术体系（CARS-30）的经费资助。

审核人：刘军伟

【英文摘要】

Manganese (Mn) toxicity poses a severe hazard to plant growth, with organic acids playing a crucial role in detoxifying toxic metals. However, the regulatory mechanisms governing the response of organic acids to Mn toxicity remain largely elusive, particularly in perennial fruit crops. Herein, we investigated the physio-biochemical and transcriptomic responses of peach seedlings to Mn toxicity. Organic acids, especially malate, significantly increased in Mn-treated peach seedlings. Subsequently, malate application markedly mitigated Mn toxicity in peach. Further, we identified a key vacuolar malate transporter, PpTDT, whose expression was dramatically induced by both Mn and malate treatments. PpTDT was localised to the vacuolar membrane. Heterologous expression of PpTDT in yeast restored growth arrest and enhanced Mn tolerance. Overexpression of PpTDT in tobacco, peach leaves and roots enhanced Mn toxicity tolerance, and increased malate and Mn content. Conversely, silencing of PpTDT in peach seedlings exacerbated Mn toxicity, resulting in decreased malate and Mn content. These findings unveil the role of PpTDT in facilitating intracellular chelation of Mn through malate transport, thereby imparting Mn toxicity tolerance in peach. Our study also highlights the potential of malate as an natural compound for improving Mn toxicity tolerance in peach and potentially other fruit crops.

论文链接：https://onlinelibrary.wiley.com/doi/10.1111/pce.15468