Grain number and seed-setting rate are components of crop yield. Cytokinin influences grain yield. However, emerging studies suggest that high cytokinin signals often lead to reduced branching or seed-setting rate, leading to reduced grain yield, although the mechanisms remain unclear. In this study, we identified and characterized the rice (Oryza sativa L.) gene LONELY GUY-LIKE 8 (LOGL8), based on anal-ysis of the LOGL8-pm (promoter mutant of LOGL8) mutant, which harbors a T-DNA insertion in the pro-moter of this gene. The mutation in LOGL8-pm causes ectopic hyperexpression of LOGL8 in inflorescence organs, resulting in plants with smaller panicles and defective ovules lacking archesporial cells and integuments. Knockout of LOGL8 caused pollen abortion, leading to a reduced seed-setting rate. LOGL8 encodes a putative cytokinin-activating enzyme. Our results showed that LOGL8 directly catalyzes the biosynthesis of bioactive cytokinins. Therefore, we propose that the ectopic expression of LOGL8 dis-rupts cytokinin spatiotemporal distribution and causes inhibition of LONELY GUY (LOG), which affects panicle branching and female organ development. These findings reveal the important role of LOGL8 in male development, and highlight the delicate balance of local cytokinin levels during panicle branching and female organ development.

Shuifu Chen;Sulin Lou;Xiucai Zhao;Shijuan Zhang;Letian Chen;Ping Huang;Guande Li;Yingying Li;Yao-Guang Liu;Yuanling Chen

State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources,South China Agricultural University,Guangzhou 510642,Guangdong,China;College of Life Sciences,South China Agricultural University,Guangzhou 510642,Guangdong,China;College of Life Sciences and Oceanography,Shenzhen University,Shenzhen 518060,Guangdong,China;Shenzhen Key Laboratory of Marine Bioresource and Eco-Environmental Science,Shenzhen 518060,Guangdong,China;Guangdong Provincial Key Laboratory for Plant Epigenetics,Shenzhen 518060,Guangdong,China;Key Laboratory of Plant Functional Genomics and Biotechnology of Guangdong Provincial Higher Education Institutions,Guangzhou 510642,Guangdong,China;Guangdong Provincial Key Laboratory of Protein Function and Regulation in Agricultural Organisms,South China Agricultural University,Guangzhou 510642,Guangdong,China

作物学报（英文版）

[1]Shuifu Chen;Sulin Lou;Xiucai Zhao;Shijuan Zhang;Letian Chen;Ping Huang;Guande Li;Yingying Li;Yao-Guang Liu;Yuanling Chen-.Ectopic expression of a male fertility gene, LOGL8, represses LOG and hinders panicle and ovule development)[J].作物学报（英文版）,2022(06):1665-1673

LOGL8,Cytokinin,LONELY,GUY,hyperexpression,archesporial,cytokinins,rupts

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