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Evaluation of the role of plant hormones involved in differential response of tomato cv. Micro-Tom to fungi of genus Alternaria and oidium through the change transcripts

Grant number: 15/00060-9
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): July 01, 2015
Effective date (End): April 10, 2017
Field of knowledge:Biological Sciences - Genetics
Cooperation agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
Principal Investigator:Antonio Vargas de Oliveira Figueira
Grantee:Jamille Santos da Silva
Home Institution: Centro de Energia Nuclear na Agricultura (CENA). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

The tomato (Solanum lycopersicum L.) is a plant model for physiological and genetic studies related to biotic stress, because it is affected by large diversity of pathogens. The cultivar Micro-Tom in particular has advantages due to its small size and reduced cycle. Plant pathogens are often classified into biotrophic, necrotrophic and hemibiotrophic according to their mechanism of infection and, consequently, different host responses are activated. Among fungal diseases, 'Early Blight' caused by Alternaria species (necrotrophic) and biotrophic powdery mildew (Oidium sp.) have infection mechanisms little known that can serve as models of the plant-pathogen interaction of contrasting lifestyles. The plant response to pathogens are known to be regulated by plant hormones. Classically, it is considered that the salicylic acid signaling is required for resistance to biotrophic pathogens, while the combination of jasmonic acid and ethylene is required for resistance against necrotrophic. However, it was observed in our laboratory that gibberellin signaling seems to participate in the infection Oidium, since a reduced number and late symptoms have been observed in mutants of this hormone signaling. Even though, little information is availabe about the molecular mechanisms of these responses regulated by these and other hormones, particularly in the case of these fungi. The objective of this study is to investigate the role of plant hormones, that respond differentially to infection, in changing the transcriptional profile of detached leaves of mutants and transgenic 'Micro-Tom' with perception or hormone synthesis changed in response to infection by Alternaria and Oidium. The project will be developed in three stages. The first will be held in order to characterize the symptoms of 'Micro-Tom' in response to infection by Alternaria and Oidium and through the expression of hormonal marker genes to determine the optimal time of collection to evaluate transcripts profiles. In the second stage, hormonal mutants and transgenic lines of 'Micro-Tom' will be evaluated based on the degree of severity of symptoms and the two mutants most contrasting will be selected. In the third, we will be evaluated the role of these hormones in differential expression of transcripts in response to infection. The analysis of this set of information will provide knowledge of the possible resistance mechanisms by hormonal signaling that the host may have in response to pathogens with contrasting lifestyles at the early of infection process. (AU)