Acta Horticulturae Sinica ›› 2022, Vol. 49 ›› Issue (6): 1247-1260.doi: 10.16420/j.issn.0513-353x.2021-0323

• Research Papers • Previous Articles     Next Articles

CsSWEET2a Promotes the Infection of Xanthomonas citri subsp. citri

MA Mingying1,2, HAO Chenxing1,2, ZHANG Kai1,2, XIAO Guihua1,2, SU Hanying1,2, WEN Kang1, DENG Ziniu1,2, MA Xianfeng1,2,*()   

  1. 1National Center for Citrus Improvement Changsha,College of Horticulture,Hunan Agricultural University, Changsha 410128,China
    2Engineering Research Center for Horticultural Crop Germplasm Creation and New Variety Breeding,Ministry of Education,Changsha 410128,China
  • Received:2021-12-10 Revised:2022-02-28 Online:2022-06-25 Published:2022-07-04
  • Contact: MA Xianfeng


After the infection of citrus canker pathogen Xanthomonas citri subsp. citriXcc),infected the leaves of the susceptible germplasm‘Bingtang’Sweet Orange,it formed typical crater bulge symptoms at the infected site,but gradually showed brown necrosis at the infected site of the leaves of the resistant germplasm Citron C-05,without typical symptoms of canker disease. Based on the transcriptome sequencing analysis of‘Bingtang’Sweet Orange and Citron C-05. leaves inoculated with Xcc,the expression of 20 CsSWEET induced by Xcc was compared. The results showed that SWEET2a and SWEET17d were up-regulated by Xcc in‘Bingtang’Sweet Orange,and SWEET12b was up-regulated by Xcc in Citron C-05;qRT-PCR verification only SWEET2a induced by Xcc high expression in ‘Bingtang’Sweet Orange and no significant change in Citron C-05,The amino acids sequence similarity of SWEET2a in different citrus germplasm homologs was 94.6%. The cis-acting elements of the promoter in‘Bingtang’Sweet Orange and Citron C-05 were significantly different in types and quantities. The transient overexpression of SWEET2a in‘Bingtang’Sweet Orange and Citron C-05 showed that SWEET2a promoted the reproduction of Xcc,and the transgenic Arabidopsis thaliana lines inoculated with the virulence strain Pst.DC3000(Pseudomonas syringae tomato DC3000)was significantly higher than that of the wild type. The SWEET2a protein is partially localized to the plasma membrane,suggesting that SWEET2a may be hijacked by Xcc for transmembrane transport of sugar extracellular to supply Xcc with energy needed for intercellular colonization.

Key words: citrus, Xcc, Citron C-05, SWEET2a, gene function

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