J Integr Plant Biol. ›› 2022, Vol. 64 ›› Issue (1): 118-134.DOI: 10.1111/jipb.13183

• Molecular Physiology • Previous Articles     Next Articles

OsRLR4 binds to the OsAUX1 promoter to negatively regulate primary root development in rice

Chendong Sun1,2,3†, Dongming Li1†, Zhenyu Gao4†, Lei Gao5, Lianguang Shang6, Mei Wang2, Jiyue Qiao2, Shilin Ding4, Chuanyou Li7, Markus Geisler8, Dean Jiang2, Yanhua Qi1,2* and Qian Qian4*   

  1. 1 Key Laboratory of Herbage & Endemic Crop Biology of Ministry of Education, Inner Mongolia Key Laboratory of Herbage & Endemic Crop Biotechnology, School of Life Sciences, Inner Mongolia University, Hohhot 010000, China
    2 State Key Laboratory of Plant Physiology and Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
    3 The Key Laboratory for Quality Improvement of Agricultural Products of Zhejiang Province, College of Advanced Agricultural Sciences, Zhejiang Agriculture and Forestry University, Lin'an Hangzhou 311300, China
    4 State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou 310006, China
    5 College of Life Sciences and Oceanography, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen University, Shenzhen, China
    6 Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518120, China
    7 State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, The Chinese Academy of Sciences, Beijing 100101, China
    8 Department of Biology, University of Fribourg, Fribourg CH‐1700, Switzerland

    These authors contributed equally to this work.
    * Correspondences: Yanhua Qi (qyhjp@zju.edu.cn, Dr. Qi is responsible for the distribution of the materials associated with this article); Qian Qian (qianqian188@hotmail.com)
  • Received:2021-07-25 Accepted:2021-10-29 Online:2021-11-03 Published:2022-01-01

Abstract: Root architecture is one of the most important agronomic traits that determines rice crop yield. The primary root (PR) absorbs mineral nutrients and provides mechanical support; however, the molecular mechanisms of PR elongation remain unclear in rice. Here, the two loss-of-function T-DNA insertion mutants of root length regulator 4 (OsRLR4), osrlr4-1 and osrlr4-2 with longer PR, and three OsRLR4 overexpression lines, OE-OsRLR4-1/-2/-3 with shorter PR compared to the wild type/Hwayoung (WT/HY), were identified. OsRLR4 is one of five members of the PRAF subfamily of the regulator chromosome condensation 1 (RCC1) family. Phylogenetic analysis of OsRLR4 from wild and cultivated rice indicated that it is under selective sweeps, suggesting its potential role in domestication. OsRLR4 controls PR development by regulating auxin accumulation in the PR tip and thus the root apical meristem activity. A series of biochemical and genetic analyses demonstrated that OsRLR4 functions directly upstream of the auxin transporter OsAUX1. Moreover, OsRLR4 interacts with the TRITHORAX-like protein OsTrx1 to promote H3K4me3 deposition at the OsAUX1 promoter, thus altering its transcription level. This work provides insight into the cooperation of auxin and epigenetic modifications in regulating root architecture and provides a genetic resource for plant architecture breeding.

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