[Phospholipase Dα1 and hydrogen sulfide were involved in the allelopathy of oridonin to Arabidopsis thaliana]

We investigated the signal relationship between phospholipase Dα1 (PLDα1) and the gas signal molecule hydrogen sulfide (H₂S) in Arabidopsis thaliana response to the allelopathy of diterpenoid oridonin. The wild type Arabidopsis Columbia (WT), phospholipase Dα1 (PLDα1) deletion mutant pldα1, D-/L-cysteine desulfyrase synthetic deletion mutant d-cdes and l-cdes seedlings were used as experiment materials, while 60 μmol·L^-1 oridonin was applied as treatment concentration. The results showed that oridonin significantly increased H₂S content, PLD and D-/L-CDes activities, and gene expressions of PLDα1 and D-/L-CDes in WT. Under oridonin treatment, the D-CDes and L-CDes activities of pldɑ1 seedlings were significantly lower than those of WT. Both D-CDes and L-CDes activities increased after exogenous addition of phosphatidic acid (PA) and were higher than those of WT. Oridonin significantly inhibited root growth of four lines, with d-cdes and l-cdes being more sensitive to oridonin. Application of NaHS promoted root growth and endogenous H₂S production of four lines under oridonin treatment, while application of PA increased root growth and endogenous H₂S production in WT, pldɑ1 and l-cdes, but had no effect in d-cdes. These results indicated that PLDα1 and H₂S played a vital role in driving the response of Arabidopsis to oridonin, and that PLDα1/PA was located at the upstream of D-CDes to participate the regulation of the H₂S production and root growth.

以拟南芥哥伦比亚野生型(WT)、磷脂酶Dα1(PLDα1)缺失型突变体pldα1、D-/L-半胱氨酸脱巯基酶(D-/L-CDes)缺失型突变体d-cdes和l-cdes幼苗为试验材料,60 μmol·L^-1冬凌草甲素为处理浓度,研究了拟南芥响应二萜类化合物冬凌草甲素的化感作用中磷脂酶Dα1(PLDα1)与气体信号分子硫化氢(H₂S)的信号关系。结果表明: 冬凌草甲素显著提高了野生型拟南芥幼苗H₂S含量、PLD和D-/L-CDes酶的活性及其基因表达;冬凌草甲素处理下,pldα1突变体幼苗的D-CDes和L-CDes活性明显低于WT,外源添加磷脂酸(PA)后D-CDes和L-CDes活性显著提高,并高于WT;冬凌草甲素显著抑制4种株系根的生长,其中d-cdes和l-cdes对冬凌草甲素更加敏感,外施NaHS可以促进冬凌草甲素处理下4种株系根的生长及内源H₂S产生,外施PA只对冬凌草甲素处理下的WT、pldα1和l-cdes株系根的生长及内源H₂S产生有促进作用,而对d-cdes株系没有明显作用。说明PLDα1和H₂S在拟南芥响应冬凌草甲素过程中发挥作用,且PLDα1/PA位于D-CDes上游,参与调控拟南芥幼苗H₂S的产生及根生长的信号过程。.

Keywords: allelopathy; hydrogen sulfide; oridonin; phospholipase Dα1.