AtPIN2基因通过影响根尖抗氧化能力参与拟南芥耐铝响应

AtPIN2 Is Involved in Aluminum Tolerance by Affecting Antioxidant Capacity in the Roots of Arabidopsis

PIN2是根尖生长素运输的重要蛋白,PIN2基因的差异表达是否影响植物耐铝性并不清楚。本文以不同AtPIN2表达水平的拟南芥为材料,研究了AtPIN2差异表达对拟南芥耐铝性的影响。结果表明,铝处理明显增强拟南芥根尖0-5 mm区域AtPIN2基因的转录表达,与对照相比,其表达量增加了80%。铝能诱导PIN2蛋白在根尖细胞膜水平方向累积,并且呈束状分布。通过分析不同AtPIN2表达材料的耐铝性,发现在铝处理条件下,PIN2缺失突变体（pin2-ko）的根系伸长速率显著小于PIN2超表达（PIN2-OX）和野生型材料（Col）;并且,pin2-ko累积较多的活性氧;pin2-ko的SOD、CAT和APX活性以及GSH含量均显著低于PIN2-OX。上述结果表明,AtPIN2表达差异影响拟南芥耐铝性,敲除AtPIN2导致其对铝毒更敏感,其机理可能是AtPIN2通过影响根尖抗氧化能力参与拟南芥耐铝响应。

PIN2 is an important auxin efflux protein. It remains unclear whether differential expression of AtPIN2 influences aluminum tolerance ofArabidopsis thaliana. In this study, the relationship between differential expression of AtPIN2 and aluminum tolerance was examined using Arabidopsis PIN2 overexpression line （PIN2-OX）, PIN2 knock-out line （pin2-ko）, and Columbia wild type （Col） as materials. AI treatment enhanced the expression of AtPIN2 in 0-5 mm root tips of Arabidopsis seedlings obviously, and its expression was in- creased by 80% in comparison to the control. A1 could induce the accumulation of PIN2 protein in the plasma membrane horizontal direction, and P1N2 protein showed a cluster distribution. Exposure to AI stress, a more serious root inhibition was observed in pin2-ko than in PIN2-OX and Col. PIN2-OX had a lower content of H202 and O2^- than pin2-ko. Exposure to A1 stress, SOD, CAT and APX activities and GSH content ofpin2-ko were lower than PIN2-OX. These results suggested that different expression of AtPIN2 influenced A1 tolerance of Arabidopsis seedling, pin2-ko was more sensitive to A1, and this might be AtPIN2 involved in aluminum tolerance by affecting antioxidant capacity.