J Integr Plant Biol ›› 2018, Vol. 60 ›› Issue (10): 938-955.DOI: 10.1111/jipb.12665

• • 上一篇    下一篇

  

  • 收稿日期:2018-04-03 接受日期:2018-05-04 出版日期:2018-10-01 发布日期:2018-10-01

Non-dormant Axillary Bud 1 regulates axillary bud outgrowth in sorghum

Jun Chen1†, Limin Zhang2†, Mengjiao Zhu1, Lijie Han1, Ya Lv1, Yishan Liu1, Pan Li1, Haichun Jing2,3,4* and Hongwei Cai1,5*   

  1. 1Department of Plant Genetics, Breeding and Seed Science, China Agricultural University; Beijing Key Laboratory of Crop Genetic Improvement; Laboratory of Crop Heterosis and Utilization, MOE; Beijing 100193, China
    2Key Laboratory of Plant Resources, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    3Inner Mongolia Research Centre for Practaculture, Chinese Academy of Sciences, Beijing 100093, China
    4University of Chinese Academy of Sciences, Beijing 100049, China
    5Forage Crop Research Institute, Japan Grassland Agricultural and Forage Seed Association, 388-5 Higashiakada, Nasushiobara, Tochigi 329-2742, Japan

    †These two authors contributed equally to this work.
    **Correspondences:
    Email: Hongwei Cai (caihw@cau.edu.cn, Dr. Cai is fully responsible for the distribution of all materials associated with this article); Haichun Jing(hcjing@ibcas.ac.cn)
  • Received:2018-04-03 Accepted:2018-05-04 Online:2018-10-01 Published:2018-10-01

Abstract: Tillering contributes to grain yield and plant architecture and therefore is an agronomically important trait in sorghum (Sorghum bicolor). Here, we identified and functionally characterized a mutant of the Non-dormant Axillary Bud 1 (NAB1) gene from an ethyl methanesulfonate-mutagenized sorghum population. The nab1 mutants have increased tillering and reduced plant height. Map-based cloning revealed that NAB1 encodes a carotenoid-cleavage dioxygenase 7 (CCD7) orthologous to rice (Oryza sativa) HIGH-TILLERING DWARF1/DWARF17 and Arabidopsis thaliana MORE AXILLARY BRANCHING 3. NAB1 is primarily expressed in axillary nodes and tiller bases and NAB1 localizes to chloroplasts. The nab1 mutation causes outgrowth of basal axillary buds; removing these non-dormant basal axillary buds restored the wild-type phenotype. The tillering of nab1 plants was completely suppressed by exogenous application of the synthetic strigolactone analog GR24. Moreover, the nab1 plants had no detectable strigolactones and displayed stronger polar auxin transport than wild-type plants. Finally, RNA-seq showed that the expression of genes involved in multiple processes, including auxin-related genes, was significantly altered in nab1. These results suggest that NAB1 functions in strigolactone biosynthesis and the regulation of shoot branching via an interaction with auxin transport.

[an error occurred while processing this directive]