Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Av. Agustín Escardino, 7, Paterna, Valencia 46980, Spain.
Plant Physiol Biochem. 2013 Sep;70:287-94. doi: 10.1016/j.plaphy.2013.06.002. Epub 2013 Jun 10.
The interplay between abscisic acid (ABA) and phospholipases A2 and D (PLA2 and PLD) in the response of citrus fruit to water stress was investigated during postharvest by using an ABA-deficient mutant from 'Navelate' orange named 'Pinalate'. Fruit from both varieties harvested at two different maturation stages (mature-green and full-mature) were subjected to prolonged water loss inducing stem-end rind breakdown (SERB) in full-mature fruit. Treatment with PLA2 inhibitor aristolochic acid (AT) and PLD inhibitor lysophosphatidylethanolamine (LPE) reduced the disorder in both varieties, suggesting that phospholipid metabolism is involved in citrus peel quality. Expression of CsPLDα and CsPLDβ, and CssPLA2α and CssPLA2β was studied by real-time RT-PCR during water stress and in response to ABA. CsPLDα expression increased in mature-green fruit from 'Navelate' but not in 'Pinalate' and ABA did not counteract this effect. ABA enhanced repression of CsPLDα in full-mature fruit. CsPLDβ gene expression decreased in mature-green 'Pinalate', remained unchanged in 'Navelate' and was induced in full-mature fruit from both varieties. CssPLA2α expression increased in mature-green fruit from both varieties whereas in full-mature fruit only increased in 'Navelate'. CssPLA2β expression increased in mature-green flavedo from both varieties, but in full-mature fruit remained steady in 'Navelate' and barely increased in 'Pinalate' fruit. ABA reduced expression in both after prolonged storage. Responsiveness to ABA increased with maturation. Our results show interplay between PLA2 and PLD and suggest that ABA action is upstream phospholipase activation. Response to ABA during water stress in citrus is regulated during fruit maturation and involves membrane phospholipid degradation.
在采后，通过使用“Navelate”甜橙的 ABA 缺陷突变体“Pinalate”研究了脱落酸 (ABA) 与磷脂酶 A2 和 D (PLA2 和 PLD) 之间的相互作用在柑橘果实对水分胁迫的反应中的作用。从两个不同成熟阶段（成熟绿和完熟）收获的两种品种的果实都经历了长时间的水分流失，导致末端果皮破裂（SERB）在完熟果实中。PLA2 抑制剂马兜铃酸（AT）和 PLD 抑制剂溶血磷脂酰乙醇胺（LPE）处理减少了两种品种的无序，表明磷脂代谢参与了柑橘果皮质量。通过实时 RT-PCR 研究了 CsPLDα 和 CsPLDβ 以及 CssPLA2α 和 CssPLA2β 在水分胁迫下和响应 ABA 时的表达。CsPLDα 在“Navelate”的成熟绿果实中表达增加，但在“Pinalate”中没有，ABA 没有抵消这种效应。ABA 增强了对 CsPLDα 在完熟果实中的抑制作用。CsPLDβ 基因表达在成熟绿的“Pinalate”中减少，在“Navelate”中保持不变，在两个品种的完熟果实中诱导。CssPLA2α 在两个品种的成熟绿果实中表达增加，而在完熟果实中仅在“Navelate”中增加。CssPLA2β 在两个品种的成熟绿果皮中表达增加，但在完熟果实中在“Navelate”中保持稳定，在“Pinalate”果实中几乎没有增加。ABA 在延长贮藏后降低了两者的表达。对 ABA 的反应性随成熟度的增加而增加。我们的结果表明 PLA2 和 PLD 之间存在相互作用，并表明 ABA 作用在上游磷脂酶激活。柑橘在水分胁迫下对 ABA 的反应在果实成熟过程中受到调节，并涉及膜磷脂的降解。
