Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan 430074, China.
Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan 430074, China.
Int J Mol Sci. 2023 Sep 5;24(18):13700. doi: 10.3390/ijms241813700.
Kiwifruit is a perennial fruit tree with high nutritional and economic value; however, various pathogen stresses have resulted in reductions in its yield and quality. Pentatricopeptide repeat proteins (PPRs), characterized by tandem repetitions of 35 amino acid motifs, play roles in RNA editing, mRNA stability, and splicing. They may also regulate plant development and growth. Nevertheless, the roles of PPRs in plant development and disease resistance remain unclear. In this study, we focused on the roles of PPRs in the fruit development and pathogen stress of kiwifruit and conducted a series of analyses of the PPR gene family in two representative kiwifruit species ( () and ()) with markedly different degrees of disease resistance. A total of 497 and 499 PPRs were identified in and , respectively. All the kiwifruit PPRs could be phylogenetically divided into four subfamilies. There were about 40.68% PPRs predicted to be localized to mitochondria or chloroplasts. A synteny analysis showed that the expansion of the kiwifruit PPRs mainly originated from segmental duplication. Based on RNA-seq data from the fruit over 12 periods of development and maturity, a weighted correlation network analysis suggested that two PPRs, Actinidia20495.t1 and Actinidia15159.t1, may be involved in fruit development and maturation. In addition, we observed different responses with respect to the expression of PPRs and RNA editing between resistant and susceptible kiwifruits following infection with pathogenic bacteria, indicating the regulatory role of PPRs in the stress response via the modulation of RNA editing. The differentially expressed upstream transcription factors of the PPRs were further identified; they may regulate resistance adaption by modulating the expression of the PPRs. Collectively, these results suggest that PPRs play roles in the development and disease resistance of kiwifruit and provide candidate genes for further clarifying the resistance mechanisms in kiwifruits.
猕猴桃是一种多年生水果树，具有很高的营养价值和经济价值；然而，各种病原体的压力导致其产量和质量下降。五肽重复蛋白（PPR）的特征是串联重复 35 个氨基酸基序，在 RNA 编辑、mRNA 稳定性和剪接中发挥作用。它们还可能调节植物的发育和生长。然而，PPR 在植物发育和抗病性中的作用仍不清楚。在这项研究中，我们专注于 PPR 在猕猴桃果实发育和病原体胁迫中的作用，并对两个具有明显不同抗病性的代表性猕猴桃物种（ （ ）和 （ ））中的 PPR 基因家族进行了一系列分析。共鉴定出 和 中的 497 个和 499 个 PPR。所有猕猴桃 PPR 都可以在系统发育上分为四个亚家族。约有 40.68%的 PPR 预测定位于线粒体或叶绿体。共线性分析表明，猕猴桃 PPR 的扩张主要来源于片段重复。基于 12 个时期的果实发育和成熟的 RNA-seq 数据，加权相关网络分析表明，两个 PPR，Actinidia20495.t1 和 Actinidia15159.t1，可能参与果实发育和成熟。此外，我们观察到，在感染病原菌后，抗性和感病猕猴桃的 PPR 和 RNA 编辑表达存在不同的反应，表明 PPR 通过调节 RNA 编辑在应激反应中发挥调节作用。进一步鉴定了 PPR 的差异表达上游转录因子；它们可能通过调节 PPR 的表达来调节抗性适应。总的来说，这些结果表明 PPR 在猕猴桃的发育和抗病性中发挥作用，并为进一步阐明猕猴桃的抗性机制提供了候选基因。
