FLAVONOIDS: A SUSTAINABLE ALTERNATIVE FOR PLANT DISEASE CONTROL AND THEIR INTERACTION WITH PLANT GROWTH-PROMOTING MICROORGANISMS

VERÓNICA VALLEJO; DAVID VILLAFAÑE; EDUARDO JOSE RODRIGUEZ; SERRA PALOMA; CASATI PAULA

Congreso; XXXIV Reunión Argentina de Fisiología Vegetal; 2023

Plant beneficial rhizospheric microorganisms have the ability to colonize the rhizosphere and enhance plant growth, development, and nutrient use efficiency through a diverse array of mechanisms. The symbiotic interactions between plant roots and associated microorganisms play a fundamental role in the overall growth and development of plants. Roots actively secrete various metabolites, including flavonoids, which serve crucial roles in physiological processes, growth, development, and stress responses. Moreover, these flavonoids have the capacity to influence the composition of the microbiome associated with the roots, thereby impacting plant growth and defense mechanisms. The primary objective of this study was to investigate the biological function of flavonoids during an infection with Pseudomonas syringae. We simultaneously studied how plants interacted with two beneficial microorganisms, Streptomyces ssp. and Trichoderma. The infection was conducted using both Arabidopsis thaliana wild type (Col-0 ecotype) and mutant plants deficient in the flavonoid biosynthetic pathway (tt4, tt5 and fls). In addition, the s3h mutant, which is a mutant in the salicylic 3-hydroxylase enzyme, was included, showing increased resistance to pathogen attacks. Treatment with Streptomyces and Trichoderma positively influenced the growth and development of both wild type and mutant plants, leading to increased seed production per plant and higher yields in greenhouse conditions. Notably, wild type plants exhibited heightened resistance against P. syringae infection. Surprisingly, the mutant plants displayed resistance to the pathogen, irrespective of the treatment with beneficial microorganisms. In conclusion, our results provide evidence that flavonoids could potentially serve as effective control agents against phytopathogens. Furthermore, they play a crucial role in mediating the interactions between plants and beneficial microorganisms, promoting growth and development.