Division site selection in Xanthomonas citri subsp. citri: caracterization of minC

Author(s)

Giordanni Cabral Dantas

• Document type: Doctoral Thesis
• Press: Rio Claro. 2016-03-30.
• Institution: Universidade Estadual Paulista (Unesp). Instituto de Biociências. Rio Claro
• Defense date: 2016-02-03
• Advisor: Henrique Ferreira

Abstract

Citriculture is one of the most important activities of Brazilian agriculturalsector. The incidence of diseases such as citrus canker affectsdrastically the orchards productivity. Its etiologic agent, the bacteriumXanthomonas citri subsp. citri (Xac) is able to infect all citric cultivars, withoutany treatment to the diseased plants.Effective control for citrus canker is the elimination of infected plants in rigorous programs to contain the spread of the bacteria. However, the recent relaxation in the policies against the fight of citrus canker in areas such as the state of São Paulo - Brazil is contributing to the further spread of the disease. The knowledge of the biology of this pathogen and also the mechanisms involved in plant-pathogen interactions are great worth in supporting the development of new strategies to deal with this disease.In this aspect, the knowledge of the biology of the plant pathogen is of great importance for the development of new strategies of control of the disease. In this paper, we study the function of ORF XAC1226, which has homology to the minC gene of E. coli. minC encodes an inhibitor protein of FtsZ polymerization and the cell division ring mounting site selection function. MinCxac shown to have a similar function as their counterparts in Escherichia coli and Bacillus subtilis. To make the functional characterization of Xac’s MinC we made a deletion which resulted in phenotypes of minicell and filamentation, which are found in E. coli and B. subtilis and we noticed that the mutant Xac minC has branches that may be related to a wrong position of the septum. Subsequently we investigated the pattern of sub-cellular GFP-MinC in Xac and noticed a protein accumulation pattern in one of the poles and a while after this protein oscillated to the opposite pole showing the same pattern of oscillation as observed in E. coli. Then we check if Xac minC lost the ability to infect the host and we inoculated it in sweet orange leaves. We found that Xac minC was able to induce cancer in leaves. We conclude that Xac uses minCDE system as septum positioning controller, which deletion does not alter virulence and MinC has the same oscillation pattern as E. coli. (AU)

• FAPESP's process: 13/19806-5 - Division site-selection in Xanthomonas citri subsp. citri: characterization of minCD
• Grantee: Giordanni Cabral Dantas
• Support Opportunities: Scholarships in Brazil - Doctorate