G protein and PLDδ are involved in JA to regulate osmotic stress responses in .

Jasmonic acid (JA) is regarded as an endogenous regulator which plays an important role in regulating plant growth, development and stress response. Using the seedlings of ecotype Col-0 (wild-type, WT), phospholipase Dδ (PLDδ) deficient mutant (), the G protein α subunit (GPA1) deficient mutant (), 9-Lipoxygenase (9-LOX) deficient mutants ( and ) as materials, the effects of JA responding to osmotic stress and the functions of G protein and PLDδ in this response were investigated. Exogenous MeJA reduced the EL and MDA in WT, but increased the EL and MDA in and , indicating that GPA1 and PLDδ were involved in the protection of JA on the membrane. The genes expression levels, and the activities of PLDδ and LOX1 were significantly induced by osmotic stress. The LOX activity and JA content in seedings were lower obviously than those in WT, but were markedly increased and were higher than WT after applying phosphatidic acid (PA). These results demonstrated that JA responded to osmotic stress by regulating G protein and PLDδ in . PLDδ was located upstream of 9-LOX and involved in the JA biosynthesis.