Searching for patterns of Citrus sinensis substances to use in biosynthesis studies

• Grant number: 23/10653-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2023
• End date: August 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Organic Chemistry
• Agreement: CNPq - INCTs
• Principal Investigator: Maria Fátima das Graças Fernandes da Silva
• Grantee: Robson de Almeida Silva
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 14/50918-7 - INCT 2014: for the Biorational Control of Pest-Insect and Phytopathogens, AP.TEM

Abstract

Huanglongbing is the most destructive citrus disease at present. In Brazil, it is associated with Candidatus Liberibacter asiaticus and Ca. L. americanus, which colonize the phloem causing gradual leaf and fruit drop and plant decline. Here. L. asiaticus is the most aggressive and widespread in citrus regions. The study of C. sinensis grafted onto C. limonia cv. Pears with and without HLB symptoms, which were examined to determine whether secondary metabolites from this plant were associated with a chemical defense response. Extracts from stems, roots and leaves were examined by UPLC-MS/MS and through these analyzes it was possible to observe a decrease in flavonoid content in aerial parts and an increase in coumarin content in roots in plants with HLB symptoms compared to controls (plants where the bacteria was not inoculated). This information suggests that the coumarin biosynthetic pathway can be used to increase resistance to the phytopathogen Ca. Liberibacter asiaticus. This led us to start studies on the biosynthesis of coumarins in citrus. Identification studies of enzymes and genes involved in the biosynthesis of hemiterpenoid coumarins in Rutaceae are under development and will provide additional information to increase the levels of these compounds and thus improve resistance against phytopathogens. A study of biosynthesis and identification of enzymes and genes involved requires comparison of spectral data and enzyme reactivity with authentic samples. In the absence of these standards, its isolation is justified, but using the opportunity to introduce a young student to science. The isolation of these patterns will allow for good learning in chromatography and spectrometry, in addition to the possibility of finding new coumarin derivatives. (AU)