Teng Ke, Yue Yuesen, Zhang Hui, Li Hui, Xu Lixin, Han Chao, Fan Xifeng, Wu Juying
Beijing Academy of Agriculture and Forestry Sciences, Beijing, China.
College of Grassland Science, Beijing Forestry University, Beijing, China.
Front Plant Sci. 2021 Dec 23;12:786570. doi: 10.3389/fpls.2021.786570. eCollection 2021.
Pheophytinase (PPH), the phytol hydrolase, plays important roles in chlorophyll degradation. Nevertheless, little attention has been paid to the PPHs in warm-season grass species; neither its detailed function in photosynthesis has been systematically explored to date. In this study, we isolated from , an excellent warm-season turfgrass species. Quantitative real-time PCR analysis and promoter activity characterization revealed that the expression of could be induced by senescence, ABA, and dark induction. Subcellular localization observation proved that ZjPPH was localized in the chloroplasts. Overexpression of accelerated the chlorophyll degradation and rescued the stay-green phenotype of the Arabidopsis mutant. Moreover, promoted senescence with the accumulation of ABA and soluble sugar contents, as well as the increased transcriptional level of and . Transmission electron microscopy investigation revealed that caused the decomposition of chloroplasts ultrastructure in stable transformed Arabidopsis. Furthermore, chlorophyll fluorescence transient measurement analysis suggested that suppressed photosynthesis efficiency by mainly suppressing both photosystem II (PSII) and photosystem I (PSI). In conclusion, plays an important role in chlorophyll degradation and senescence. It could be a valuable target for genetic editing to cultivate new germplasms with stay-green performance and improved photosynthetic efficiency.
脱镁叶绿酸酶（PPH），即植醇水解酶，在叶绿素降解过程中发挥着重要作用。然而，暖季型草种中的PPH却很少受到关注；迄今为止，其在光合作用中的详细功能也尚未得到系统研究。在本研究中，我们从优良的暖季型草坪草物种[具体物种名称未给出]中分离出了[ZjPPH基因未给出]。定量实时PCR分析和启动子活性表征表明，[ZjPPH基因未给出]的表达可被衰老、脱落酸（ABA）和黑暗诱导所诱导。亚细胞定位观察证明ZjPPH定位于叶绿体中。[ZjPPH基因未给出]的过表达加速了叶绿素降解，并挽救了拟南芥[具体突变体名称未给出]的持绿表型。此外，[ZjPPH基因未给出]促进了衰老，伴随着ABA和可溶性糖含量的积累，以及[相关基因未给出]和[相关基因未给出]转录水平的增加。透射电子显微镜研究表明，[ZjPPH基因未给出]导致了稳定转化拟南芥中叶绿体超微结构的分解。此外，叶绿素荧光瞬态测量分析表明，[ZjPPH基因未给出]主要通过抑制光系统II（PSII）和光系统I（PSI）来抑制光合作用效率。总之，[ZjPPH基因未给出]在叶绿素降解和衰老过程中发挥着重要作用。它可能是基因编辑的一个有价值的靶点，用于培育具有持绿性能和提高光合效率的新种质。
