Acta Horticulturae Sinica ›› 2023, Vol. 50 ›› Issue (2): 250-264.doi: 10.16420/j.issn.0513-353x.2021-1188

• Research Papers • Previous Articles     Next Articles

Effect of R2R3-MYB Transcription Factor CitMYB21 on Flavonoids Biosynthesis in Citrus

YE Zimao1, SHEN Wanxia1,2,*(), LIU Mengyu1, WANG Tong1, ZHANG Xiaonan1, YU Xin1,2, LIU Xiaofeng1,2, ZHAO Xiaochun1,2,*()   

  1. 1. Citrus Research Institute,Southwest University/Chinese Academy of Agricultural Sciences,Chongqing 400712,China
    2. National Citrus Engineering Research Center,Chongqing 400712,China
  • Received:2022-08-08 Revised:2022-10-19 Online:2023-02-25 Published:2023-03-06
  • Contact: *(


Brazil Sour Orange(Citrus aurantium L.),Bendizao Mandarin(C. reticulata Blanco),Guihuadinanfeng mandarin(C. reticulata Blanco),Jincheng Beibei 447[C. sinensis(L.)Osbeck] and other 30 germplasms were used for mining the transcription factors related to flavonoid biosynthesis. Comparative transcriptomic analysis revealed that ERF,MYB and Dof transcription factor families are significantly involved in metabolism of flavonoids during fruit development. Correlation analysis of the expressions of CitCHS2,a key gene of flavonoids biosynthesis with the differentially expressed genes from transcriptomic analysis indicated that two R2R3-MYB family member CitMYB21(Ciclev10021699m)and CitMYB33(Ciclev10012152m)were negatively correlated to expression of CitCHS2. Phylogenic analysis revealed that these two genes belong to SG2 and SG1 subgroup of R2R3-MYBs family,respectively. The full length of CitMYB21 coding region is 804 bp and encodes 267 amino acids. The expressions of CitMYB21 were highly tissue and genotype specific,and significantly negatively correlated with the flavonoids contents. Silence of CitMYB21 resulted a significant increase of flavonoids in the leaf of transgenic plants,while transient overexpression of CitMYB21 in the peel of citrus fruit led to a significant decrease of flavonoids. Results of this study indicated that expression of CitMYB21 negatively affect the flavonoid biosynthesis in citrus,suggesting CitMYB21 may be an important transcription factor negatively regulating the biosynthesis of flavonoid.

Key words: citrus, flavonoids, R2R3-MYB transcription factor, negative regulation, tissue specific

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