Distéfano Ayelen M, Valiñas Matías A, Scuffi Denise, Lamattina Lorenzo, Ten Have Arjen, García-Mata Carlos, Laxalt Ana M
a Instituto de Investigaciones Biológicas-CONICET; Universidad Nacional de Mar del Plata ; Mar del Plata , Argentina.
Plant Signal Behav. 2015;10(11):e1089371. doi: 10.1080/15592324.2015.1089371.
Phospholipase D (PLD) is involved in different plant processes, ranging from responses to abiotic and biotic stress to plant development. Phospholipase Dδ (PLDδ) is activated in dehydration and salt stress, producing the lipid second messenger phosphatidic acid. In this work we show that pldδ Arabidopsis mutants were more tolerant to severe drought than wild-type plants. PLDδ has been shown to be required for ABA regulation of stomatal closure of isolated epidermal peels. However, there was no significant difference in stomatal conductance at the whole plant level between wild-type and pldδ mutants. Since PLD hydrolyses structural phospholipids, then we looked at membrane integrity. Ion leakage measurements showed that during dehydration of leaf discs pldδ mutant has less membrane degradation compared to the wild-type. We further analyzed the mutants and showed that pldδ have higher mRNA levels of RAB18 and RD29A compared to wild-type plants under normal growth conditions. Transient expression of AtPLDδ in Nicotiana benthamiana plants induced a wilting phenotype. These findings suggest that, in wt plants PLDδ disrupt membranes in severe drought stress and, in the absence of the protein (PLDδ knock-out) might drought-prime the plants, making them more tolerant to severe drought stress. The results are discussed in relation to PLDδ role in guard cell signaling and drought tolerance.
磷脂酶D(PLD)参与植物的多种生理过程,从对非生物和生物胁迫的响应到植物发育。磷脂酶Dδ(PLDδ)在脱水和盐胁迫下被激活,产生脂质第二信使磷脂酸。在本研究中,我们发现拟南芥pldδ突变体比野生型植物更耐受严重干旱。已有研究表明,PLDδ是脱落酸(ABA)调节离体表皮条气孔关闭所必需的。然而,野生型和pldδ突变体在整株水平上的气孔导度没有显著差异。由于PLD水解结构磷脂,因此我们研究了膜的完整性。离子渗漏测量表明,在叶片脱水过程中,与野生型相比,pldδ突变体的膜降解较少。我们进一步分析了这些突变体,发现与正常生长条件下的野生型植物相比,pldδ突变体中RAB18和RD29A的mRNA水平更高。在本氏烟草植株中瞬时表达AtPLDδ会诱导萎蔫表型。这些发现表明,在野生型植物中,PLDδ在严重干旱胁迫下破坏膜结构,而在缺乏该蛋白(PLDδ基因敲除)的情况下,可能会使植物产生干旱记忆,使其更耐受严重干旱胁迫。我们结合PLDδ在保卫细胞信号传导和耐旱性方面的作用对结果进行了讨论。