Science and Technology Production
Congress
Authorship
SERRA, PALOMA
;
Aramburu, Silvana Righini
;
Dillon, Francisco
;
Ferreyra, María Lorena Falcone
;
Grotewold, Erich
;
Casati, Paula
Date
2021
Publishing House and Editing Place
Maize Genetics Coorporation
Summary
Information provided by the agent in
SIGEVA
Flavonoids represent an important group of specialized metabolites synthesized in plants. Flavones, one of the most important flavonoids, are synthesized by enzymes known as flavone synthases (FNSs). There are two different types of FNS enzymes: flavone synthase I (FNSI) enzymes are soluble Fe+2/2-oxoglutarate-dependent dioxygenases (2-ODDs); while flavone synthases II (FNSII) belong to a family of NADPH- and oxygen-dependent cytochrome P450 membrane-bound monooxygenases. Both enzymes catalyze ...
Flavonoids represent an important group of specialized metabolites synthesized in plants. Flavones, one of the most important flavonoids, are synthesized by enzymes known as flavone synthases (FNSs). There are two different types of FNS enzymes: flavone synthase I (FNSI) enzymes are soluble Fe+2/2-oxoglutarate-dependent dioxygenases (2-ODDs); while flavone synthases II (FNSII) belong to a family of NADPH- and oxygen-dependent cytochrome P450 membrane-bound monooxygenases. Both enzymes catalyze the conversion of the flavanone naringenin into the main flavone, apigenin. In the model organism Arabidopsis thaliana, Downey Mildew Resistant 6 (DMR6) encodes an FNSI type enzyme. dmr6 mutant plants show increased resistance against the attack of multiple pathogens, including Pseudomonas syringae, associated to an accumulation of the hormone salicylic acid (SA). Furthermore, there is a restoration of susceptibility to the pathogen attack when dmr6 plants are complemented with FNS I and II from maize. The aim of this work is to study the possible interconnection between flavones synthesis and salicylic acid metabolism. Thus, we analyzed the susceptibility against the attack of the pathogen Pseudomonas syringae in Arabidopsis wild type (Col-0 ecotype) and mutant plants in SALICYLIC ACID 3-HIDROXYLASE (S3H) gene. Salicylic acid 3-hydroxylase enzyme catalyzes the conversion of salicylic acid to 2,3-dihydrobenzoic acid. Therefore, s3h mutants accumulate higher levels of salicylic acid that results in enhanced resistance to infection by pathogens. The infection experiments were also carried out in s3h mutant plants expressing FNS I and II enzymes from maize. Transgenic lines expressing either ZmFNSI or II exhibited restoration of susceptibility to Pseudomonas infection. We also quantified the level of salicylic acid and apigenin in transgenic lines post-infection. Results show that the restoration of susceptibility observed is consequence of decreased SA levels and an augmentation of apigenin biosynthesis. In order to analyze if other flavonoids, besides flavones, were involved in the response of plants to biotic stress, infection experiments were also performed in plants carrying mutations in genes of the flavonoids biosynthetic pathway. In addition, we analyzed the possible regulatory effect of flavonoids on the expression of genes associated with SA metabolism using RT-qPCR. Together, our results suggest that there is a connection between flavone synthesis and SA metabolism.
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Key Words
SALICYLIC ACIDBIOTIC STRESSFLAVONES