根毛缺陷基因RHD6调控植物耐铝性的生理及分子机理

铝（Al）毒害是酸性土壤上限制作物生产的主要因子之一。明确植物对铝胁迫的耐性机制，发掘植物耐铝关键基因，是利用现代生物技术手段改良植物营养遗传性状，最终培育适应酸性铝毒土壤植物新品种的前提。我们前期在对拟南芥铝耐性调控转录因子突变体筛选中发现，根毛缺陷基因RHD6参与了对植物耐铝性的调控，且RHD6基因的敲除导致根细胞壁中铝的积累量显著增高。本项目拟在前期研究的基础上，结合生理生化、细胞学、遗传学及分子生物学等手段，继续深入探讨铝胁迫下RHD6调控植物耐铝的生理和分子机理，阐明铝胁迫下AtALMT1和AtMATE调控的根系有机酸分泌、细胞壁组成或结构变化以及根毛数目变化在RHD6调控植物耐铝性中的作用；明确铝胁迫下STOP1和GL2与RHD6间的调控关系及机理；筛选RHD6下游结合调控关键基因，明确其在耐铝性调控中的作用。为最终阐明RHD6调控植物耐铝性的生理和分子机理提供依据。

Aluminum (Al) toxicity is one of the major limiting factors for crop production in acid soil. Understanding of the physiological and molecular resistance mechanism of plants to Al stress is the prerequirement for the improvement of yield in the breeding for adaptation to Al toxicity in acid soil. We previously have found that the loss of function mutant rhd6 (root hair defective 6) shows a highly enhanced root-growth sensitivity to Al stress, and more Al accumulated in the cell wall of rhd6 roots compared to that of the wild-type plants. To further better understand the physiological and molecular regulation mechanism of RHD6 in Al resistance, the present study will combine the physiological, biochemical, cellular, genetic and molecular approaches and further analyse (i): the potential involvement of AtALMT1- and AtMATE-regulated organic acid exudation from roots, modification of cell-wall composition or structure and root hair number in RHD6-regulated Al resistance; (ii): the regulatory network among STOP1, GL2 and RHD6, and their roles in Al resistance; (iii) the down-regulated target genes of RHD6 and clarify their molecular and physiological functions.