花生根系高效活化和吸收磷素的生理及分子机制研究

Peanut (Arachis hypogaea L.) is a phosphorus loving leguminous crop. It is very sensitive to phosphorus fertility. Available phosphorus deficiency is an important factor which limits the improvement of peanut yield in china. So increasing phosphorus uptake efficiency is an important way to increase yield of peanut. Crop phosphorus activation ability and absorption ability are key factors that determining phosphorus absorption efficiency, which are very different between genotypes. The project is to take a series of peanut genotypes with different phosphorus efficiency as test materials, which were screened out in our previous study. Under the stress of low phosphorus, the kinds and amount of organic acids, H+ concentration, acid phosphatase activity, protein composition and variation, and relative expression of Pi transporters genes are to be detected in root and its secretion. Furthermore, we will study the phosphorus activation ability and absorption ability differences between peanut genotypes and their relationship with phosphorus efficiency. Reveal the key root exudates affecting phosphorus activation and the key gene determining the phosphorus absorption capacity. And point out which is the limiting factors for phosphorus efficiency, phosphorus activation ability or absorption ability. Guided by the above theory, new technology aimed at regulating phosphorus activation or absorption efficiency can be developed, and also related technology of regulating soil phosphorus supply and fertilizer. Moreover, breeders can develop new varieties with high phosphorus efficiency based on molecular markers associated with high phosphorus efficiency. The goal of "double reduction" will be achieved from cultivation or breeding way.

花生是豆科喜磷作物，对供磷水平反应敏感，有效磷匮缺是我国花生生产的重要限制因素。提高磷吸收效率是花生生产节本增效的重要途径。作物活化土壤无效磷的能力和吸收能力是决定磷吸收效率的两个关键因子。本项目以前期筛选的不同磷吸收效率花生基因型为试验材料，检测低磷胁迫处理后磷素吸收效率、根系分泌有机酸的种类和数量、酸性磷酸酶活性、磷转运蛋白基因表达量、蛋白质组成及变化规律变化等，比较基因型间磷活化能力和吸收能力的差异，明确限制磷吸收效率的因素是活化能力还是吸收能力，发掘调控花生磷素活化和吸收的关键基因及网络，解析花生对磷素高效吸收及耐低磷的分子机制。这为栽培上研制施肥或土壤调理技术、育种上开发磷高效分子标记、培育磷吸收效率高的品种提供理论基础，从栽培和育种两个途径实现资源高效利用，达到“双减”目标。

花生是喜磷作物，有效磷匮缺是限制我国花生生产的重要因素。提高磷吸收效率是促进花生生产的重要途径。作物活化土壤无效磷的能力和吸收能力是决定磷吸收效率的两个关键因子。项目进行了低磷条件下磷吸收对花生产量的贡献、花生活化/吸收磷的能力及机制、基因型间磷吸收效率差异机制等方面的研究，取得重要进展。.明确低磷条件下磷吸收效率对产量的贡献增强，磷吸收效率强的材料更适合在低磷条件下种植。建立水培法鉴定花生种质活化/吸收效率的方法体系。鉴定评价了235份花生种质活化/吸收磷素的能力，筛选出48份磷活化/吸收高效种质。明确磷活化效率对磷活化能力的贡献大于根系形态；低磷胁迫下，较大的根体积和平均根直径对提高磷活化能力亦有较大贡献；有机酸分泌量和种类的增加在促进活化效率方面均有重要作用。磷吸收效率对磷吸收能力的贡献大于根系形态；低磷处理下根系形态对磷吸收能力的贡献大于足磷处理；低磷胁迫下，较大的根表面积、总根长和根干重对获得较高的磷吸收能力也有较大贡献；磷吸收动力学参数中以Imax值对磷高效品种的高净磷吸收速率的贡献最大；鉴定出5个响应低磷胁迫表达的PHT1基因，其中AhPHT1;17可能参与了花生磷素吸收。花生种质高效活化/吸收有两种策略，一是低磷胁迫下根系生长被促进且活化/吸收效率提高，另一种是根系生长未被促进，但活化/吸收效率显著提高。.筛选出24份磷活化高效种质，26份磷吸收高效种质，19份双高种质。以花育22、山花14号为例，解析种质磷高效的差异机制。低磷胁迫下，花育22具有较高的磷活化能力，能将更多无效磷转化为有效磷，较大的根表面积和根体积以及较强的单位根干重磷吸收效率促进了有效磷的吸收；山花14号较强的单位根表面积磷吸收效率促进了磷素吸收。.研究结果为栽培上研制施肥或土壤调理技术、育种上开发磷高效分子标记、培育磷吸收效率高的品种提供理论基础，从栽培和育种两个途径实现磷素资源高效利用，达到“双减”目标。