Abstract The involvement of different isoforms of genes encoding phospholipases D (CsPLDα, CsPLDβ, CsPLDδ, CsPLDγ and CsPLDζ) and A2 (CsPLA2α, CsPLA2β and CsPAT1) on starvation-induced postharvest non-chilling peel pitting (NCPP) has been compared in the inner (albedo) and outer (flavedo) parts of the peel of citrus fruit treated or not with sucrose (Suc). The study has been performed in Navelate (Citrus sinensis (L.) Osbeck) sweet orange, which is prone to NCPP, stored under non-stressful environmental conditions (90–95 % relative humidity (RH) and 20 °C). Transcriptional changes, as well as respiration rate and ATP content evolution during fruit storage were compared in both peel tissues. Results indicated that the albedo is more susceptible than the flavedo to starvation; and that, at early stress stage, ATP and all CsPLD isoforms and CsPLA2β are good indicators of carbon starvation in the albedo, and CsPLDβ in the flavedo. These carbon starvation-induced signals were not activated when Suc was applied as an external energy source. In the second phase of starvation, expression of all CsPLD-encoding genes increased with NCPP; and CsPLDγ and CsPLDζ showed major increases in both peel tissues. The correlation of the expression of CsPLA isoforms with damage development was lower. In this phase, Suc may protect the fruit by providing additional energy sources to sustain respiration; and by favouring phospholipid-derived signaling messengers mediated by CsPLDβ and CsPAT1 in the albedo, CsPLDζ in the flavedo, and CsPLA2β in both tissues. Results from the examination of changes in gene expression point out tissue specificities in the expression of CsPL genes but also different susceptibility to starvation between the flavedo and the albedo in citrus fruit.

中文翻译：

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磷脂酶和蔗糖参与柑橘类水果碳饥饿诱导的非冷果皮点蚀

摘要 编码磷脂酶 D（CsPLDα、CsPLDβ、CsPLDδ、CsPLDγ 和 CsPLDζ）和 A2（CsPLA2α、CsPLA2β 和 CsPAT1）的基因的不同亚型对饥饿诱导的采后非冷皮点蚀 (NCPP) 的参与已在内部进行了比较。用或未用蔗糖 (Suc) 处理过的柑橘类水果果皮的（反照率）和外部（flavedo）部分。该研究是在 Navelate（Citrus sinensis (L.) Osbeck）甜橙中进行的，该甜橙易于发生 NCPP，储存在无压力的环境条件下（90-95% 相对湿度 (RH) 和 20 °C）。在两种果皮组织中比较了水果储存过程中的转录变化、呼吸速率和 ATP 含量演变。结果表明，反照率比flavedo更容易挨饿；而且，在早期的压力阶段，ATP 和所有 CsPLD 同种型以及 CsPLA2β 是反照率中碳饥饿的良好指标，以及淡化中 CsPLDβ。当 Suc 用作外部能源时，这些碳饥饿诱导的信号没有被激活。在饥饿的第二阶段，所有 CsPLD 编码基因的表达都随着 NCPP 的增加而增加；CsPLDγ 和 CsPLDζ 在两种果皮组织中均表现出显着增加。CsPLA 亚型的表达与损伤发展的相关性较低。在这个阶段，Suc 可以通过提供额外的能量来维持呼吸来保护水果；并且通过有利于由反照率中的 CsPLDβ 和 CsPAT1、flavedo 中的 CsPLDζ 和两种组织中的 CsPLA2β 介导的磷脂衍生信号信使。