Functional Characterization of the Pheophytinase Gene, , From in Regulating Chlorophyll Degradation and Photosynthesis.

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.