[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.