PLDα1介导ABA调控的拟南芥主根伸长并参与根毛生长

探讨了磷脂酶Dα1（PLDα1）在ABA抑制拟南芥主根伸长过程中的作用。PLOα1基因突变体pldα1主根伸长受ABA抑制小于野生型（WT）；根系PLDα1活性在ABA处理下升高；拟南芥根细胞原生质体中活性氧（ROS）含量在ABA处理下升高，但是pldα1升高小于WT；根系NADPH氧化酶活性在ABA处理下升高，pldα1升高小于WT，外源加入10μmol/L^-1 PA（磷脂酸，PLD水解产物）后，前者活性显著升高；外源加入H2O2可诱导WT和pldα1主根伸长都受到抑制，且二者差异不明显。结果表明，PLDα1产生的PA通过激活NADPH氧化酶产生ROS介导ABA调控的拟南芥主根伸长过程。此外，初步探讨了PLDα1在拟南芥根毛尖端生长中的作用：pldα1突变体根毛长度小于WT，根毛尖端ROS和Ca^2＋浓度低于WT。

PLDα1 Modulated ABA-Mediated Main Root Elongation and Regulated Tip Growth of Root Hair in Arabidopsis

The role of PLDα1 in ABA inhibition of main root elongation in Arabidopsis was studied. When the seedlings were treated with ABA, elongation of main root of wild-type （WT） was inhibited more obviously than that of pldα1. In main root protoplasts, the activity of both PLDα1 and NADPH oxidase increased under ABA treatment, and the NADPH oxidase activity increased much more in WT than in pldα1. When 10μmol L^-1 PA was added into the growth medium, the NADPH oxidase activity increased in pldα1 protoplasts. The concentration of ROS in Arabidopsis root protoplasts increased more quickly in WT than in pldα1 after ABA addition. When H2O2 was added into the culture medium, main root elongation was inhibited in both genotypes. All these results suggested that, PA produced by PLDα1 acted as a regulator in ABA- mediated root elongation in Arabidopsis via NADPH oxidase-produced ROS. In addition, root hair of pldα1 was shorter than that of WT. On the tip of root hair, pldα1 had lower concentration of ROS and Ca^2＋ than WT.