PLDdelta is involved in NO induced stomatal closure

DISTEFANO AYELEN.MARIANA; GARCÍA-MATA CARLOS; LAMATTINA LORENZO; LAXALT ANA MARÍA

Rosario, Santa Fé, Argentina

Congreso; Sociedad Argentina de Fsiología Vegetal (SAFV).; 2008

Sociedad Argentina de Fsiología Vegetal (SAFV).

Previously we have shown that, in Vicia faba guard cells, nitric oxide (NO) induces stomatal closure via activation of phospholipase D (PLD) with the consequent production of phosphatidic acid. Multiple PLD isoforms exist. Arabidopsis has 12 with distinguishable biochemical and regulatory properties, and also with little functional redundancy. Two isoforms, PLDalpha1 and delta had been related to stomatal closure and drought response upon ABA treatments. Our current goal is to determine whether PLDalpha1 and PLDdelta are required for NO induced stomatal closure. As a measure of stomatal closure we evaluate the leaf loss of fresh weight (LFW), since LFW is largely determined by stomatal conductance. NO treated wild type plants shows less LFW than non-treated plants, reflecting the fact that NO induces stomatal closure. In pldalpha1 plants, NO treatment partially avoided the reduction of LFW; but it has no effects on LFW of plddelta and pldalpha1-plddelta mutants. These results were corroborated by direct microscopic stomata observation in epidermal peels of NO-treated wild type and mutants plants. This indicates that during stomatal closure NO could be activating PA accumulation via PLDdelta and partially via PLDalpha. Futures studies will be done to directly measure in vivo PLD activity upon NO treatments in Arabidopsis.