Suppression of glycolate oxidase causes glyoxylate accumulation that inhibits photosynthesis through deactivating Rubisco in rice

• DOI: 10.1111/ppl.12104
• Publication Date: 2013-10-08T15:20:48Z
• Authors: Yusheng Lu; Yong Li; Qiaosong Yang; Zhisheng Zhang; Yan Chen; Sheng Zhang; Xin‐Xiang Peng
• Keywords: C4 Photosynthesis; Photorespiration

Glycolate oxidase (GLO) is a key enzyme for photorespiration in plants. Previous studies have demonstrated that suppression of GLO causes photosynthetic inhibition, and the accumulated glycolate with deactivated Rubisco likely involved regulation. Using isolated chloroplasts, it has been found only glyoxylate can effectively inactivate meanwhile inhibit photosynthesis, but little vivo evidence acquired reported. In this study, we generated transgenic rice (Oryza sativa) plants being constitutively silenced, conducted physiological biochemical analyses on these to explore regulatory mechanism. When was downregulated, net rate (Pn) reduced plant growth correspondingly stunted. Surprisingly, glyoxylate, as product catalysis, response suppression, like its substrate glycolate. Furthermore, content be inversely proportional Pn while directly activation state GLO-suppressed A mathematical fitting equation using least square method also content. Despite further failed reveal how current results do strongly suggest there may exist an unidentified, alternative pathway produce inhibits photosynthesis by deactivating Rubisco, photorespiratory phenotype