Chinese Bulletin of Botany ›› 2020, Vol. 55 ›› Issue (1): 5-8.DOI: 10.11983/CBB20002

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A New Progress of Green Revolution: Epigenetic Modification Dual-regulated by Gibberellin and Nitrogen Supply Contributes to Breeding of High Yield and Nitrogen Use Efficiency Rice

Mei-ling Han1,2,Ru-jiao Tan1,3,Dai-yin Chao1,*()   

  1. 1National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
    2University of Chinese Academy of Sciences, Beijing 100049, China
    3Jiangsu Normal University, Xuzhou 221000, China
  • Received:2020-01-07 Accepted:2020-01-13 Online:2020-01-01 Published:2020-02-07
  • Contact: Dai-yin Chao

Abstract: The Green Revolution represented by the breeding of semi-dwarf crops greatly promoted agriculture yield, but it also unfortunately led to the problem of low nitrogen use efficiency (NUE). The achievement of Green Revolution was mainly based on modification of gibberellin (GA) metabolic or signaling pathways in crops. A previous study has found that the central regulator of GA signaling pathway DELLA protein negatively regulates NUE through suppressing GRF4, an essential NUE regulator, which provided a resolution for improving NUE of semi-dwarf rice. A recent study further revealed a novel mechanism underlying the crosstalk between GA signaling and nitrogen response. The study revealed that NGR5 is a key gene controlling tiller number changes under different nitrogen conditions, which is inducible by nitrogen. Further investigation established that the NGR5 suppresses branching inhibitory genes, such as D14 and OsSPL14, through nitrogen-dependent recruitment of polycomb repressive complex 2 that promotes histone H3 lysine 27 tri-methylation in the regions habouring the branching suppressors. In addition to be responsive to nitrogen, NGR5 is also negatively regulated by GA and its receptor GID, and overexpression of NGR5 in the semi-dwarf background is thus able to significantly improve rice yields under low nitrogen conditions. This study not only uncovered a new mechanism of GA signaling, but also enlightens the new generation of Green Revolution by breeding high yield crops with enhanced NUE.

Key words: rice, tiller number, nitrogen use efficiency, histone modification