BOTRYOID POLLEN 1 regulates ROS-triggered PCD and pollen wall development by controlling UDP-sugar homeostasis in rice

Authors：Chen, Huiqiong; Zhang, Shuqing; Li, Ruiqi; Peng, Guoqing; Chen, Weipan; Rautengarten, Carsten; Liu, Minglong; Zhu, Liya; Xiao, Yueping; Song, Fengshun; Ni, Jinlong; Huang, Jilei; Wu, Aimin; Liu, Zhenlan; Zhuang, Chuxiong; Heazlewood, Joshua L.; Xie, Yongyao^*; Chu, Zhizhan^*; Zhou, Hai^*

Source：Plant Cell, 2023, 35(9): 3522-3543.

DOI：10.1093/plcell/koad181

• PROGRAMMED CELL-DEATH
• ANTHER CUTICLE
• MALE-STERILITY
• 4-EPIMERASE ISOFORMS
• MONOCLONAL-ANTIBODY
• EXINE FORMATION
• PROTEIN
• BIOSYNTHESIS
• ENCODES
• GENE

Uridine diphosphate (UDP)-sugars are important metabolites involved in the biosynthesis of polysaccharides and may be important signaling molecules. UDP-glucose 4-epimerase (UGE) catalyzes the interconversion between UDP-Glc and UDP-Gal, whose biological function in rice (Oryza sativa) fertility is poorly understood. Here, we identify and characterize the botryoid pollen 1 (bp1) mutant and show that BP1 encodes a UGE that regulates UDP-sugar homeostasis, thereby controlling the development of rice anthers. The loss of BP1 function led to massive accumulation of UDP-Glc and imbalance of other UDP-sugars. We determined that the higher levels of UDP-Glc and its derivatives in bp1 may induce the expression of NADPH oxidase genes, resulting in a premature accumulation of reactive oxygen species (ROS), thereby advancing programmed cell death (PCD) of anther walls but delaying the end of tapetal degradation. The accumulation of UDP-Glc as metabolites resulted in an abnormal degradation of callose, producing an adhesive microspore. Furthermore, the UDP-sugar metabolism pathway is not only involved in the formation of intine but also in the formation of the initial framework for extine. Our results reveal how UDP-sugars regulate anther development and provide new clues for cellular ROS accumulation and PCD triggered by UDP-Glc as a signaling molecule. @@@ UDP-Glc and its derivatives induce the expression of NADPH oxidase genes, inducing ROS-triggered PCD as signaling molecules, but also regulate pollen wall development as metabolites.

• Institution
  广东省农业科学院; 华南农业大学