OsRRM, an RNA-Binding Protein, Modulates Sugar Transport in Rice (Oryza sativa L.)

Derui Liu; Lina Xu; Wei Wang; Shuwen Jia; Sukui Jin; Jiping Gao

doi:10.3389/fpls.2020.605276

OsRRM, an RNA-Binding Protein, Modulates Sugar Transport in Rice (Oryza sativa L.)

Front Plant Sci. 2020 Dec 8:11:605276. doi: 10.3389/fpls.2020.605276. eCollection 2020.

Authors

Derui Liu^{1

2}, Lina Xu^{1

2}, Wei Wang^{1

2}, Shuwen Jia^{1

2}, Sukui Jin^{1

2}, Jiping Gao^{1

2

3}

Affiliations

¹ Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Key Laboratory of Crop Genomics and Molecular Breeding of Jiangsu Province, Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, College of Agriculture, Yangzhou University, Yangzhou, China.
² National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
³ Innovation Academy for Seed Design, Chinese Academy of Sciences, Beijing, China.

Abstract

Sugar allocation between vegetative and reproductive tissues is vital to plant development, and sugar transporters play fundamental roles in this process. Although several transcription factors have been identified that control their transcription levels, the way in which the expression of sugar transporter genes is controlled at the posttranscriptional level is unknown. In this study, we showed that OsRRM, an RNA-binding protein, modulates sugar allocation in tissues on the source-to-sink route. The OsRRM expression pattern partly resembles that of several sugar transporter and transcription factor genes that specifically affect sugar transporter gene expression. The messenger RNA levels of almost all of the sugar transporter genes are severely reduced in the osrrm mutant, and this alters sugar metabolism and sugar signaling, which further affects plant height, flowering time, seed size, and starch synthesis. We further showed that OsRRM binds directly to messenger RNAs encoded by sugar transporter genes and thus may stabilize their transcripts. Therefore, we have uncovered the physiological function of OsRRM, which sheds new light on sugar metabolism and sugar signaling.

Keywords: Oryza sativa; RNA binding protein; Spen-like; sugar signaling; sugar transport.