Suppressing a phosphohydrolase of cytokinin nucleotide enhances grain yield in rice

Author: Bi Wu, Jianghu Meng, Hongbo Liu, Donghai Mao, Huanran Yin, Zhanyi Zhang, Xiangchun Zhou, Bo Zhang, Ahmed Sherif, Haiyang Liu, Xianghua Li, Jinghua Xiao, Wenhao Yan, Lei Wang, Xingwang Li, Wei Chen, Weibo Xie, Ping Yin, Qifa Zhang & Yongzhong Xing

Nature Genetics. 27 Jul 2023

Abstract:One-step and two-step pathways are proposed to synthesize cytokinin in plants. The one-step pathway is mediated by LONELY GUY (LOG) proteins. However, the enzyme for the two-step pathway remains to be identified. Here, we show that quantitative trait locus GY3 may boost grain yield by more than 20% through manipulating a two-step pathway. Locus GY3 encodes a LOG protein that acts as a 5′-ribonucleotide phosphohydrolase by excessively consuming the cytokinin precursors, which contrasts with the activity of canonical LOG members as phosphoribohydrolases in a one-step pathway. The residue S41 of GY3 is crucial for the dephosphorylation of iPRMP to produce iPR. A solo-LTR insertion within the promoter of GY3 suppressed its expression and resulted in a higher content of active cytokinins in young panicles. Introgression of GY302428 increased grain yield per plot by 7.4% to 16.3% in all investigated indica backgrounds, which demonstrates the great value of GY302428 in indica rice production.

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