Plant Molecular Biology

, Volume 93, Issue 4–5, pp 341–353 | Cite as

Transgenic citrus expressing synthesized cecropin B genes in the phloem exhibits decreased susceptibility to Huanglongbing

  • Xiuping ZouEmail author
  • Xueyou Jiang
  • Lanzhen Xu
  • Tiangang Lei
  • Aihong Peng
  • Yongrui He
  • Lixiao Yao
  • Shanchun ChenEmail author


Key message

Expression of synthesized cecropin B genes in the citrus phloem, where Candidatus Liberibacter asiaticus resides, significantly decreased host susceptibility to Huanglongbing.


Huanglongbing (HLB), associated with Candidatus Liberibacter asiaticus bacteria, is the most destructive disease of citrus worldwide. All of the commercial sweet orange cultivars lack resistance to this disease. The cationic lytic peptide cecropin B, isolated from the Chinese tasar moth (Antheraea pernyi), has been shown to effectively eliminate bacteria. In this study, we demonstrated that transgenic citrus (Citrus sinensis Osbeck) expressing the cecropin B gene specifically in the phloem had a decreased susceptibility to HLB. Three plant codon-optimized synthetic cecropin B genes, which were designed to secrete the cecropin B peptide into three specific sites, the extracellular space, the cytoplasm, and the endoplasmic reticulum, were constructed. Under the control of the selected phloem-specific promoter GRP1.8, these constructs were transferred into the citrus genome. All of the cecropin B genes were efficiently expressed in the phloem of transgenic plants. Over more than a year of evaluation, the transgenic lines exhibited reduced disease severity. Bacterial populations in transgenic lines were significantly lower than in the controls. Two lines, in which bacterial populations were significantly lower than in others, showed no visible symptoms. Thus, we demonstrated the potential application of the phloem-specific expression of an antimicrobial peptide gene to protect citrus plants from HLB.


Citrus Huanglongbing Cecropin B Phloem-specific promoter Disease resistance Genetic transformation 



This work was supported by grants from the National Natural Sciences Foundation of China (31272150, to XZ), the Earmarked Fund for China Agriculture Research System (CARS-27, to SC), and the Fundamental Research Funds for the Central Universities (XDJK2012B023, to XZ).

Author contributions

XZ designed the experiments, constructed the vectors, and wrote the manuscript. LX and AP performed the citrus genetic transformations. XJ evaluated the resistance to HLB. TL and YH performed molecular analyses. LY performed the Southern blot analysis. SC analyzed the data. All of the authors read and approved the manuscript.

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflicts of interest.

Supplementary material

11103_2016_565_MOESM1_ESM.docx (1.9 mb)
Supplementary material 1 (DOCX 1918 KB)


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Copyright information

© Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  • Xiuping Zou
    • 1
    • 2
    Email author
  • Xueyou Jiang
    • 2
    • 3
  • Lanzhen Xu
    • 1
    • 2
  • Tiangang Lei
    • 1
    • 2
  • Aihong Peng
    • 1
    • 2
  • Yongrui He
    • 1
    • 2
  • Lixiao Yao
    • 1
    • 2
  • Shanchun Chen
    • 1
    • 2
    Email author
  1. 1.Citrus Research InstituteChinese Academy of Agricultural Sciences/National Center for Citrus Variety ImprovementChongqingPeople’s Republic of China
  2. 2.Citrus Research InstituteSouthwest UniversityChongqingPeople’s Republic of China
  3. 3.Guangan Agricultural BureauChongqingPeople’s Republic of China

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