Phospholipase D δ knock-out mutants are tolerant to severe drought stress

DISTÉFANO A.M; VALIÑAS, M; SCUFFI D; LAMATTINA L; ARJEN TEN HAVE; GARCIA-MATA C; LAXALT AM

Plant Signaling and Behavior

Taylor and Francis

Año: 2015

Phospholipase D (PLD) is involved in different plant processes, ranging from responses toabiotic and biotic stress to plant development. Phospholipase Dd (PLDδ) is activated indehydration and salt stress, producing the lipid second messenger phosphatidic acid. Inthis work we show that pldδ Arabidopsis mutants were more tolerant to severe droughtthan wild-type plants. PLDδ has been shown to be required for ABA regulation ofstomatal closure of isolated epidermal peels. However, there was no significantdifference in stomatal conductance at the whole plant level between wild-type and pld dmutants. Since PLD hydrolyses structural phospholipids, then we looked at membraneintegrity. Ion leakage measurements showed that during dehydration of leaf discs pld dmutant has less membrane degradation compared to the wild-type. We further analyzedthe mutants and showed that pldδ have higher mRNA levels of RAB18 and RD29Acompared to wild-type plants under normal growth conditions. Transient expression ofAtPLDd in Nicotiana benthamiana plants induced a wilting phenotype. These findingssuggests that, in wt plants PLDd disrupt membranes in severe drought stress and, theabsence of the protein (PLDd knock-out) might drought-primed the plants, making themmore tolerant to severe drought stress. The results are discussed in relation to PLDd rolein guard cell signalling and drought tolerance.