Role of genes and metabolites involved in polyamines synthesis pathways and nitric oxide synthase in stomatal closure on Rosa damascena Mill. under drought stress.

In order to evaluate the genes involved in polyamines synthesis pathway and the role of nitric oxide synthase (NOS) and H2O2 in stomatal closure under drought stress, a research conducted with three irrigation levels (100, 50 and 25% field capacity) at 1, 3, 6 and 12 days on Rosa damascena Mill. HPLC and qPCR results showed that putrescine (Put) accumulation occurred at first day in both 50 and 25% of field capacity and then decreased the other days. Furthermore, Put accumulation in the indirect pathway (ADC, AIH and CPA) was more effective related to the direct pathway (ODC) under severe stress. Increased expression of genes involved in production of spermidine (Spd) and spermine (Spm) i.e., SAMDC, SPDS and SPMS correlated with the highest accumulation of Spd and Spm under 50% FC at 6 d and 25% FC at 12 d, respectively. Moreover, results showed that Put reduction simultaneously accumulated H2O2, which subsequently increased NOS expression suggesting a key signal for stomatal closure.