重金属诱导的柳树离子组变异及其元素稳态重建机制

Heavy metal(HM) contamination is a widespread and important environmental concern. Various in situ and ex situ cleanup technologies have been employed, of which phytoremediation is promising due to its low implementation costs and significant environmental benefits. Under the selective pressure of high concentration of HMs, minerals and HMs homeostasis are crucial for HM resistance in plants. The micro-distribution of HMs in roots of Salix integra were detected by synchrotron-based micro-X-ray fluorescence (μ-XRF) in the previous studies and indicating the critical role of apoplastic barriers in the selective entry of HMs into the vascular system. To elucidate the mechanisms of apoplastic barriers in controlling the ion homeostasis, in this project, the ionomic variation in different tissues of S. integra were determined by ionomics method for the purpose of understanding the interactions of mineral elements and HMs. Differences in the development of apoplastic barriers in roots of S. integra in the presence of cadmium(Cd)was furtherly investigated to illustrate the regulative role of the secondary deposition of cell wall in maintaining ion homeostasis. Using noninvasive microtest technology (NMT) and transcriptomic sequencing, the Cd dynamic uptake in roots and the interaction mechanism with responsive genes related in the transport of other bivalent cations might be revealed, and the molecular regulative network for ion homeostasis will be constructed. The results would actually provide the theoretical basis for breeding of new willow varieties with high biomass and heavy metal accumulation.

土壤重金属污染是全球面临的重要环境问题，当前国际上治理大面积土壤重金属污染最经济有效的方法是植物修复技术。在高浓度重金属的选择压力下，维持体内重金属和矿质营养的离子平衡，对提高植物重金属的抗性至关重要。前期采用同步辐射X-射线荧光（XRF）技术构建了杞柳（Salix integra）根系重金属的微区分布图谱，发现根系非原生质体屏障对重金属的滞留作用。为进一步了解这种滞留作用对重金属和矿质元素吸收平衡的调控机制，本项目采用离子组学方法，继续以杞柳为研究对象，通过分析不同组织离子谱的变异，阐明重金属和矿质元素在杞柳体内的互作方式；进一步分析镉对根部非原生质体屏障发育的影响，揭示根细胞壁次生加厚对离子稳态的调控机制；结合非损伤微测技术和转录组学方法，研究二价阳离子转运蛋白对镉积累能力的贡献，从而构建杞柳体内离子稳态机制的分子调控网络，为选育具有高生物量和重金属高积累量的柳树新品种奠定理论基础。