Identification of two glycerophosphodiester phosphodiesterase genes in maize leaf phosphorus remobilization

• 作者: Jingxin Wang Wenbo Pan Alexiy Nikiforov William King Wanting Hong Weiwei Li Yang Han Jana Patton-Vogt Jianbo Shen Lingyun Cheng
• 来源期刊: 作物学报（英文版）
• 年，卷（期）: 2021,（1）
• 所属期刊栏目: Research Papers
• 页码范围: 95-108
• 页数: 14页
• 语种: 英文

摘要

Phosphate deficiency is one of the leading causes of crop productivity loss. Phospholipid degradation liberates phosphate to cope with phosphate deficiency. Glycerophosphodiester phosphodiesterases (GPX-PDEs) hydrolyse the intermediate products of phospholipid catabolism glycerophosphodiesters into glycerol-3-phosphate, a precursor of phosphate. However, the function of GPX-PDEs in phosphate remobilization in maize remains unclear. In the present study, we characterized two phosphate deficiency-inducible GPX-PDE genes, ZmGPX-PDE1 and ZmGPX-PDE5, in maize leaves. ZmGPX-PDE1 and ZmGPX-PDE5 were transcriptionally regulated by ZmPHR1, a well-described phosphate starvation-responsive transcription factor of the MYB family. Complementation of the yeast GPX-PDE mutant gde1Δindicated that ZmGPX-PDE1 and ZmGPX-PDE5 functioned as GPX-PDEs, suggesting their roles in phosphate recycling from glycerophosphodiesters. In vitro enzyme assays showed that ZmGPX-PDE1 and ZmGPX-PDE5 catalysed glycerophosphodiester degradation with different substrate preferences for glycerophosphoinositol and glycerophosphocholine, respectively. ZmGPX-PDE1 was upregulated during leaf senescence, and more remarkably, loss of ZmGPX-PDE1 in maize compromised the remobilization of phosphorus from senescing leaves to young leaves, resulting in a stay-green phenotype under phosphate starvation. These results suggest that ZmGPX-PDE1 catalyses the degradation of glycerophosphodiesters in maize, promoting phosphate recycling from senescing leaves to new leaves. This mechanism is crucial for improving phosphorus utilization efficiency in crops.