OsAlR2调控水稻耐铝的功能分析OA

[Objective]Study was carried out to investigate the function of the aluminum tolerance-related gene OsAlR2 under aluminum stress,and to elucidate the regulatory mechanism by which OsAlR2 participates in regulating aluminum stress responses.[Methods]In our previous study,an aluminum tolerance-related gene OsAlR2 was identified.The knockout mutant ko-alr2 and overexpression mutant oe-alr2 were generated,and the phenotypes and physiological mechanisms of these lines were analyzed.[Results]After aluminum treatment,the root length and root activity of oe-alr2 were lower than those of the wild type,whereas no significant differences were observed between ko-alr2 and the wild type.In terms of aluminum content,the Al³ ⁺ content in ko-alr2 was significantly lower than that in the wild type,while no obvious difference was found in oe-alr2 compared with the wild type.Subsequent section observation showed that root cells of oe-alr2 exhibited varying degrees of damage after aluminum treatment,whereas no obvious damage was detected in the wild type and ko-alr2.Under aluminum stress,the MDA content in oe-alr2 was significantly higher than that in the wild type,while the MDA content in ko-alr2 was markedly lower.Assays of the reactive oxygen species-scavenging enzymes CAT and SOD revealed that the activities of CAT and SOD in ko-alr2 were significantly higher than those in the wild type,whereas the activities in oe-alr2 were lower.The expression levels of several known aluminum tolerance genes,including OsFRDL2,OsSTAR1,and OsCDT3,were determined.Under aluminum stress,the transcript levels of OsSTAR1 and OsCDT3 in ko-alr2 were significantly upregulated and higher than those in the wild type,while the opposite pattern was observed in oe-alr2.[Conclusion]These results demonstrate that the OsAlR2 gene is involved in regulating the defense of rice against aluminum toxicity.It negatively regulates aluminum tolerance in rice by modulating reactive oxygen species-scavenging capacity and the expression of aluminum tolerance-related genes.This study lays a foundation for further revealing the regulatory mechanism of this gene in response to aluminum stress at the rice seedling stage.