Genetic manipulation of endogenous citrus phytoalexins to increase resistance to specific pathogens (Phytophthora citrophthora)

• Grant number: 23/12362-6
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: December 01, 2023
• End date: November 30, 2025
• Field of knowledge: Biological Sciences - Biochemistry - Molecular Biology
• Agreement: CNPq - INCTs
• Principal Investigator: Sérgio Florentino Pascholati
• Grantee: Jéssica Cristina Amaral
• Host Institution: Escola Superior de Agricultura Luiz de Queiroz (ESALQ). Universidade de São Paulo (USP). Piracicaba , SP, Brazil

Abstract

Several compounds are important metabolites that contribute to the defense of plants against the attack of phytopathogens and insects. Many of these are hemiterpenes, containing C5 prenyl groups attached to the carbon atoms of heterocyclic systems, and they presented as phytoalexins or phytoanticipins associated with resistance to pathogens of citrus such as Phytophthora citrophthora, Xylella fastidiosa and Candidatus liberibacter, and most of these studies have been carried out by our group. Aromatic prenyltransferases catalyze the transfer of isoprenoids diphosphates to aromatic compounds. This family of enzymes can be classified in three types: cytosolic ABBA (±-²-²-± barrel) type, dimethylallyltryptophan synthase (DMATS) type and membrane-embedded UbiA type. Prenylation of aromatic rings in plants is catalyzed by prenyltransferases (PTs) belonging to the membrane-bound UbiA protein superfamily. Several enzymes as PTs and cytochrome P450 monooxygenases (P450s) of the hemiterpenoid compounds pathway have been isolated and characterized, and most of the work in this area has been conducted by Alain Hehn at "Laboratoire Agronomie et Environnement-LAE", at Université de Lorraine, France. The preliminary results obtained so far by our group in collaboration with Heln's group, allow directing studies of genetic engineering on the biosynthesis of hemiterpenoid compounds. Thus, the sequence of this work in the identification of enzymes involved in the biosynthesis of hemiterpenoid compounds in citrus will provide important information for genetic engineering in order to increase the levels of these compounds and, thus, improve resistance against phytopathogens, mainly against Phytophthora, in addition to creating conditions to produce new fungicides to protect citrus crop.