Citron C-05 inhibits both the penetration and colonization of subsp. to achieve resistance to citrus canker disease.

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TitleCitron C-05 inhibits both the penetration and colonization of subsp. to achieve resistance to citrus canker disease.
Publication TypeJournal Article
Year of Publication2020
AuthorsFu, H, Zhao, M, Xu, J, Tan, L, Han, J, Li, D, Wang, M, Xiao, S, Ma, X, Deng, Z
JournalHortic Res
Date Published2020

Citrus canker, caused by subsp. (), is a serious bacterial disease that affects citrus production worldwide. Citron C-05 () is the only germplasm in the genus that has been identified to exhibit strong resistance to . However, it has not been determined when, where, and how is restricted in the tissues of Citron C-05 during the infection process. In the present study, we investigated the spatiotemporal growth dynamics of an -labeled virulent () strain in Citron C-05 along with five susceptible biotypes (i.e., lemon, pummelo, sour orange, sweet orange, and ponkan mandarin) upon inoculation via the spraying or leaf infiltration of a bacterial suspension. The results from extensive confocal laser scanning microscopy analyses showed that while grew rapidly in plants of all five susceptible genotypes, was severely restricted in the epidermal and mesophyll cell layers of the leaves of Citron C-05 in the early stage of infection. Not surprisingly, resistance against in Citron C-05 was found to be associated with the production of reactive oxygen species and hypersensitive response-like cell death, as well as greater upregulation of several defense-related genes, including a pathogenesis-related gene () and a glutathione S-transferase gene (), compared with sweet orange as a susceptible control. Taken together, our results not only provide further valuable details of the spatiotemporal dynamics of the host entry, propagation, and spread of in both resistant and susceptible citrus plants but also suggest that resistance to in Citron C-05 may be attributed to the activation of multiple defense mechanisms.

Alternate JournalHortic Res
PubMed ID32377349
PubMed Central IDPMC7193574