ARBUSCULAR MYCORRHIZA SYMBIOSIS REDUCES THE RHIZOCTONIA ROOT ROT AND ALTERS THE PHENOLIC PROFILE IN COMMON BEAN

Arbuscular mycorrhizal fungi (AMF) have the potential to reduce the deleterious effect of soil-borne pathogens, but their ability for pathogen biocontrol may vary depending on the genotype of the plant, the pathogen, and the AMF interaction. Thus, the aim of this work was to evaluate the effect of the Mexican biofertilizer Rizofermic-UV based on a mix of AMF formulation against the common bean root rot caused by the pathogenic fungus Rhizoctonia solani Kühn 1858 (Teleomorph: Thanatephorus cucumeris). Additionally, the total phenolic content, individual phenolic acid (caffeic, ferulic, o-cumaric, p-cumaric, sinapic, and vanillic), and the flavonoid (catechin, kaempherol, quercetin, and rutin) profiles were analyzed. Our results show that the AMF biofertilization reduces the disease severity up to 68 %, and this was accompanied by a boost in total phenolic content in dual inoculation. Furthermore, a variation in the individual phenolic profiles caused by both AMF interaction and pathogen treatment alone were observed. In dual inoculations, vanillic acid was significantly different among treatments, suggesting it may contribute to the enhanced resistance of mycorrhizal roots to soil-borne pathogens. Further work is required to elucidate the exact role of these compounds in the bioprotection of arbuscular mycorrhizal to plant pathogens.