College of Plant Protection, Shenyang Agricultural University, Shenyang, China.
College of Horticulture, Shenyang Agricultural University, Shenyang, China.
Physiol Plant. 2023 May-Jun;175(3):e13925. doi: 10.1111/ppl.13925.
Type 2C protein phosphatases (PP2Cs) play key roles in regulating plant senescence and ripening. Here, we discovered a subfamily F PP2C, SlPP2C, associated with leaf senescence through transcriptome analysis. The gene expression, protein accumulation, and promoter activity of SlPP2C all gradually increased along with the progression of leaf and flower senescence and fruit ripening in tomato. Also, the expression of SlPP2C was highly up-regulated by the senescent-inducible hormone treatments, showing more sensitivity to ethylene (ETH) and abscisic acid (ABA). Meanwhile, SlPP2C RNA interference (RNAi) tomato transgenic lines showed obvious delayed senescence and ripening phenotypes of leaves, flowers, and fruits. SlPP2C RNAi lines delayed leaf senescence with higher chlorophyll fluorescence and content, and lower expressions of senescence marker genes (SlSGR1 and SlSAG12) compared to WT. SlPP2C RNAi lines clearly delayed flower senescence time; it was at least twice longer than WT. SlPP2C RNAi lines delayed fruit ripening, exhibiting higher firmness and lower polygalacturonase activity compared to WT. In addition, we proved that SlPP2C is unable to interact with any of the ABA receptors (SlPYLs). Together, the results demonstrate that SlPP2C is a senescence-related and ripening-related gene.
2C 型蛋白磷酸酶（PP2Cs）在调控植物衰老和成熟过程中发挥着关键作用。在这里，我们通过转录组分析发现了一个与叶片衰老相关的亚家族 F PP2C，即 SlPP2C。番茄叶片和花衰老以及果实成熟过程中，SlPP2C 的基因表达、蛋白积累和启动子活性均逐渐增加。此外，SlPP2C 的表达受衰老诱导激素处理的高度上调，对乙烯（ETH）和脱落酸（ABA）表现出更高的敏感性。同时，SlPP2C RNA 干扰（RNAi）番茄转基因系表现出明显的叶片、花和果实衰老和成熟延迟表型。SlPP2C RNAi 系延迟叶片衰老，具有更高的叶绿素荧光和含量，以及更低的衰老标记基因（SlSGR1 和 SlSAG12）表达，与 WT 相比。SlPP2C RNAi 系明显延迟了花的衰老时间，比 WT 至少长两倍。SlPP2C RNAi 系延迟了果实成熟，表现出更高的硬度和更低的多聚半乳糖醛酸酶活性，与 WT 相比。此外，我们证明 SlPP2C 无法与任何 ABA 受体（SlPYLs）相互作用。总之，这些结果表明 SlPP2C 是一个与衰老和成熟相关的基因。
