茶树耐土壤钾贫瘠的根系响应及其调控机制研究

As one of the most important nutrients, potassium plays an important role in improving the quality, yield and resistance of tea. Due to natural and human factors, soil potassium deficiency has become a universal constraint of tea production. The response and regulation mechanisms of root morphology, physiology and molecular are important plant adaptations to potassium deficiency. In our previous studies, two specific tea materials, which had similar genetic backgrounds but extremely different low-potassium tolerance abilities and root developments, were obtained through artificial hybridization, field and laboratory screening. In this proposed project, systematic studies of root response and regulation in resistance to low-potassium stress of tea will be conducted. Split pot experiments will be conducted, via root scanner and non-invasive microelectrode technique, to study root morphological and physiological responses (such as root plasticity, root exudate activation, proton efflux and so on) to low-potassium stress. In addition, next generation sequencing technology will be used to dig key genes related to potassium efficient capacity of tea root. Such efforts will not only contribute to our further understanding of response and regulation mechanisms of root morphology, physiology and molecular in improving low-potassium tolerance ability of tea, but also help to provide theoretical basis and technical support for alleviation of soil potassium deficiency in tea gardens and variety breeding of tea with high resistance to low-potassium stress.

钾作为重要的营养元素之一，在提高茶树品质、产量与抗性方面都具有重要作用。由于自然和人为原因，茶园土壤缺钾严重，已成为茶叶生产的普遍限制因素。缺钾条件下根系形态、生理与分子的响应与调控机制是植物抵御钾贫瘠的一种重要适应机制。本课题组通过前期人工杂交、田间与室内研究，筛选出遗传背景相近但根系和耐低钾能力极端分离的两个特异茶树单株材料。本项目拟在此基础上，针对目前茶树耐低钾胁迫中根系响应与调控研究的薄弱环节，围绕当前根系生物学热点展开系统研究。通过分根试验，结合根系原位监测、非损伤性微测（NMT）与高通量测序（NGS）技术，原位研究根构型重塑、根系分泌物活化、质子分泌等形态与生理响应对茶树耐贫钾能力的影响，挖掘与茶树根系钾高效相关的关键基因。以期明确茶树根系形态、生理与分子的响应与调控在提高其耐土壤贫钾能力上的作用机制，为缓解茶园土壤钾匮乏和耐土壤钾贫瘠茶树品种的培育提供理论基础和技术支持。

钾作为重要的营养元素之一，在提高茶树品质、产量与抗性方面都具有重要作用。由于自然和人为原因，茶园土壤缺钾严重，已成为茶叶生产的普遍限制因素。缺钾条件下根系形态、生理与分子的响应与调控机制是植物抵御钾贫瘠的一种重要适应机制。本课题组以前期选育的遗传背景相近但根系和耐低钾能力极端分离的两个特异茶树单株为材料，通过根系原位监测、非损伤性微测（NMT）与高通量测序（NGS）技术等，对比分析两个单株在根构型重塑、根系分泌物活化等形态与生理响应对茶树耐贫钾能力的影响，挖掘与茶树根系钾高效相关的关键基因。取得了如下研究成果：（1）耐低钾型比钾敏感型茶树根际土壤钾库能储存更多的缓效钾。（2）在低钾胁迫时，耐低钾型茶树能有效提高细根生长，从而促进钾吸收，而钾敏感型茶树则趋向于发育粗根。（3）耐低钾型茶树对外界钾的感知更灵敏，供钾能有效提高耐低钾型茶树根系分泌物对土壤钾素的活化能力。（4）耐低钾胁迫关键基因包括：乙烯、铵转运蛋白、硝酸盐转运蛋白和磷脂酰肌醇，暗示茶树可能存在氮-钾互作。. 通过本项目的研究工作，发表SCI论文5篇，获得实用新型专利授权1项，培养了1名硕士研究生。本项目的研究，为缓解茶园土壤钾匮乏和耐土壤钾贫瘠茶树品种的培育提供理论基础和技术支持。