Journal of Integrative Agriculture ›› 2024, Vol. 23 ›› Issue (5): 1454-1467.DOI: 10.1016/j.jia.2023.05.041

所属专题: 水稻遗传育种合辑Rice Genetics · Breeding · Germplasm Resources

• • 上一篇    下一篇

生长素转运基因OsAUX1调控水稻分蘖发育

  


  1.  


  • 收稿日期:2023-03-09 接受日期:2023-05-05 出版日期:2024-05-20 发布日期:2024-04-23

The auxin transporter OsAUX1 regulates tillering in rice (Oryza sativa)

Luqi Jia1, Yongdong Dai1, Ziwei Peng1, Zhibo Cui1, Xuefei Zhang1, Yangyang Li1, Weijiang Tian1, Guanghua He1, Yun Li2, Xianchun Sang1#   

  1. 1 Chongqing Key Laboratory of Crop Molecular Improvement/Rice Research Institute, Academy of Agricultural Sciences, Southwest University, Chongqing 400715, China

    2 Rice and Sorghum Research Institute, Sichuan Academy of Agricultural Sciences/Key Laboratory of Southwest Rice Biology and Genetic Breeding, Ministry of Agriculture and Rural Affairs, Deyang 618000, China

  • Received:2023-03-09 Accepted:2023-05-05 Online:2024-05-20 Published:2024-04-23
  • About author:Luqi Jia, E-mail: 632063809@qq.com; #Correspondence Xianchun Sang, Tel/Fax: +86-23-68251264, E-mail: sangxianchun@163.com
  • Supported by:
    This work was supported by the National Key Research and Development Program of China (2022YFD1201600), the National Natural Science Foundation of China (32171964) and the Science Fund for Creative Research Groups of Chongqing, China (cstc2021jcyj-cxttX0004).

摘要: 分蘖是重要农艺性状,其通过影响有效穗从而进一步影响水稻(Oryza sativa)产量。生长素在分蘖发育中起关键作用。本文鉴定一个多蘖半矮化突变体(htsd1),其根部表现出生长素缺陷的侧根侧根密度降低角度增大等特征。突变体htsd1对生长素的敏感性降低,外施生长素可部分抑制分蘖发育htsd1突变性状调控基因为LOC_Os01g63770该基因编码生长素转运蛋白OsAUX1。OsAUX1启动子区域含有大量SPLSQUAMOSA PROMOTER BINDING PROTEIN-LIKE转录因子家族结合位点,鉴定发现SPL7可以直接结合到OsAUX1启动子区域。分蘖负调控关键基因OsTB1TEOSINTE BRANCHED1 htsd1突变体中极显著下降。OsTB1敲除突变体中分蘖数增加,外施生长素可以抑制OsTB1敲除突变体分蘖芽的生长htsd1突变中过表达OsAUX1基因可恢复少蘖表型。这些结果表明,SPL7可以直接结合到OsAUX1启动子区域进而调控OsTB1的表达,从而通过IAA途径调控水稻分蘖数的发育。

Abstract: Tillering is an important agronomic trait of rice (Oryza sativa) that affects the number of effective panicles, thereby affecting yields.  The phytohormone auxin plays a key role in tillering.  Here we identified the high tillering and semi-dwarf 1 (htsd1) mutant with auxin-deficiency root characteristics, such as shortened lateral roots, reduced lateral root density, and enlarged root angles.  htsd1 showed reduced sensitivity to auxin, but the external application of indole-3-acetic acid (IAA) inhibited its tillering.  We identified the mutated gene in htsd1 as AUXIN1 (OsAUX1, LOC_Os01g63770), which encodes an auxin influx transporter.  The promoter sequence of OsAUX1 contains many SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) binding sites, and we demonstrated that SPL7 binds to the OsAUX1 promoter.  TEOSINTE BRANCHED1 (OsTB1), a key gene that negatively regulates tillering, was significantly downregulated in htsd1.  Tillering was enhanced in the OsTB1 knockout mutant, and the external application of IAA inhibited tiller elongation in this mutant.  Overexpressing OsTB1 restored the multi-tiller phenotype of htsd1.  These results suggest that SPL7 directly binds to the OsAUX1 promoter and regulates tillering in rice by altering OsTB1 expression to modulate auxin signaling.

Key words: rice (Oryza sativa L.) ,  tillering ,  indole-3-acetic acid (IAA) ,  OsAUX1 ,  OsTB1