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Study of variation of chemical profile of lemon (C. limon) of orange (C. sinensis) and Tahiti lime (C. latifolia) before and after inoculation with Phyllosticta citricicarpa and fungal strains related to infection by RNA viruses

Grant number: 15/09208-9
Support Opportunities:Scholarships in Brazil - Doctorate
Effective date (Start): August 01, 2015
Effective date (End): July 31, 2020
Field of knowledge:Physical Sciences and Mathematics - Chemistry - Organic Chemistry
Acordo de Cooperação: Coordination of Improvement of Higher Education Personnel (CAPES)
Principal Investigator:Maria Fátima das Graças Fernandes da Silva
Grantee:Hocelayne Paulino Fernandes
Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
Associated scholarship(s):18/23144-1 - NMR-based metabolomics for monitoring metabolic alteration of citrus species caused by Phyllosticta citricarpa, BE.EP.DR


The citrus black spot (MPC) or blight, caused by the fungus Phyllosticta citricarpa affects orange, tangerine, lemon and pomeleiros, being found in Africa, Asia, Oceania and South America. With the exception of sour orange (C. aurantium) and their hybrids, and acid lime Tahiti (C. latifolia), all commercial varieties are susceptible, especially the real lemon (C. limon), which play a fundamental role in the onset of epidemics of disease, and orange (C. sinensis) medium-late maturing (Pear) and late (Natal and Valência). In São Paulo have occurred up to 100% of fruit affected in areas where not made any kind of control. The organs attacked by the MPC may be in order of frequency: fruits, leaves, stems, petioles, green branches and thorns. The MPC is of great economic importance because it causes aesthetic depreciation fruit and is detrimental to marketing the same in nature in foreign markets. When there is high infection in developing fruits stalk region may be premature fall reflecting in this way in production. This information shows the great need for a program to control the MPC. For the implementation of this program different areas researchers were aggregated into network, and these have been using the scientific knowledge and experience to improve the MPC control practices. The metabolites which a microorganism synthesizes are connected with their respective ecological niche. This not only synthesize metabolites need to compete with other pathogens to colonize the host, but also to regulate its metabolism in the host balanced combination. P. citricarpa is in contact with their hosts citrus, forming an intriguing and challenging plant-microorganism double for scientific studies, which would be unprecedented in the literature. Initially intended to undertake the study of variation of chemical profile of citrus after inoculation of the fungus P. citricicarpa. It will be inoculated with the fungus true leaves and lemon tahiti lime and evaluated the variation of secondary metabolites in plant development using analytical methods such as HPLC-UV, LC-UV-SPE-NMR and chemometric tools. The leaves of acid lime Tahiti may be a fungal reservoir in the sexual phase as G. citricarpa and responsible for the transfer of the pathogen to other organs and planting areas. Increase in the content of some secondary metabolite in the plant may be related to the internal defense mechanisms induced. That is, understanding how the plant defends this microorganism will provide information of new pesticides to P. citricarpa. Furthermore, the isolation of tyrosol P. citricicarpa urged further research into the possible function of the same pathogenic event in Citrus, since there are reports in the literature on studies of the signal and self-regulatory activity of this molecule in some endophytes. In an attempt to verify this effect of tyrosol, it is intended to apply solutions at different concentrations on the leaves of the true plants lemon and lime Tahiti acid and evaluate whether the appearance of symptoms similar to those caused by the fungus P. citricicarpa. These inoculations and chemical profile of the above studies will also be conducted in the fruits of Valencia orange. Some isolates of P. citricarpa have infection by RNA virus double-stranded (dsRNA) with phenotypic effects still unknown. According to the literature cured strain shows an increase in virulence, which indicates a phenotype associated with hipovirulento dsRNA. The hipovirulent phenotype may show a different chemical profile, or a secondary metabolite in larger quantities. The results of this proposal also open possibilities of studies in genetic engineering on the biosynthesis of the compounds found, with the induction of resistance in citrus possibilities. (AU)

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