Abscisic acid (ABA) plays a vital role in coordinating physiological processes during fresh fruit ripening. ABA can bind to ABA receptors which interacts and inhibits their co-receptors type 2C phosphatases (PP2Cs). However, the dissected mechanism of PP2C during fruit ripening is unclear. In this study, we identify the role of SlPP2C3, a tomato type 2C phosphatase, as a negative regulator of ABA signaling and fruit ripening. SlPP2C3 selectively interacted with monomeric ABA receptors and SlSnRK2.8 kinase in both yeast and tobacco epidermal cells. Expressions of SlPP2C3 were observed in all tissues, and it negatively correlated with the fruit ripening which was induced by exogenous ABA. Tomato plants with suppressed SlPP2C3 expression exhibited enhanced sensitivity to ABA, while SlPP2C3 over-expressed plants were less sensitive to ABA. Meaningfully, lack of SlPP2C3 expression causes the acceleration of fruit ripening onset via the alternation of ABA signaling activity, and the fruit gloss is affected by the changes of outer epidermis structure. RNA-seq analysis found significant different expression of cuticle-related genes in pericarp between wild-type and SlPP2C3 suppressed lines. Taken together, our finding demonstrate that SlPP2C3 plays an important role in the regulation of fruit ripening and fruit appearance quality in tomato.

中文翻译：

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番茄蛋白磷酸酶2C（SlPP2C3）负调节水果成熟的开始和水果的光泽

脱落酸（ABA）在新鲜水果成熟期间协调生理过程中起着至关重要的作用。ABA可以与ABA受体结合，后者相互作用并抑制其2C型磷酸共受体（PP2Cs）。然而，PP2C在果实成熟过程中的分解机理尚不清楚。在这项研究中，我们确定了番茄2C型磷酸酶SlPP2C3作为ABA信号传导和果实成熟的负调节剂。S1PP2C3在酵母和烟草表皮细胞中与单体ABA受体和S1SnRK2.8激酶选择性相互作用。在所有组织中均观察到SlPP2C3的表达，其与外源ABA诱导的果实成熟呈负相关。具有抑制的SlPP2C3表达的番茄植株表现出对ABA的增强敏感性，而过量表达的SlPP2C3植株对ABA的敏感性较低。有意义的是，SlPP2C3表达的缺乏会导致通过ABA信号转导活性的改变而加速果实成熟的开始，并且果实的光泽度受外部表皮结构变化的影响。RNA-seq分析发现野生型和SlPP2C3抑制品系在果皮中表皮相关基因的表达差异显着。综上所述，我们的发现表明SlPP2C3在调节番茄果实成熟和果实外观质量中起着重要作用。