The native strain Paenibacillus sp. A224 mitigates stress caused by high temperatures and by the pathogen Sclerotium rolfsii in peanut plants by inducing systemic tolerance

FIGUEREDO, MARÍA SOLEDAD; ÁLAMO, TAMARA; TONELLI, MARÍA LAURA; FABRA, ADRIANA

Congreso; XXX REUNION LATINOAMERICANA DE RIZOBIOLOGÍA V CONFERENCIA LATINOAMERICANA DE MICROORGANISMOS PROMOTORES DEL CRECIMIENTO VEGETAL; 2021

The native strain Paenibacillus sp. A224 mitigates stress caused by high temperatures and by the pathogen Sclerotium rolfsii in peanut plants by inducing systemic toleranceFigueredo MS, Álamo T, Tonelli, ML., Fabra A.Instituto de Investigaciones Agrobiotecnológicas (CONICET-UNRC). Universidad Nacional de Río Cuarto. Río Cuarto. Córdoba, Argentina. mfigueredo@exa.unrc.edu.arThe frequency of the occurrence of combined biotic and abiotic stresses is likely to increase in the future. Therefore, the need to develop strategies to enhance the tolerance of crop to combined stresses is evident. Peanut production is one of the most important agricultural activities in the province of Córdoba, Argentina. Different biotic and abiotic factors negatively affect the yield of this crop. We proposed to identify, in the available collection of bacteria isolated from the peanut rhizosphere or phylosphere, those whose inoculation protect against the simultaneous effects of abiotic (high temperature, 35 °C for 6 days) and biotic (Sclerotium rolfsii) stresses.The plantlet?s radicles were inoculated with the peanut microsymbiont and pure cultures of 8 different bacterial isolates and, after 7 days, the shoots were challenged with S. rolfsii and exposed to 35 °C for 6 days. At 30 days post-bacterial inoculation, the incidence of the disease, the plant biomass and number and dry weight of nodules were determined. In plants co-inoculated with peanut microsymbiont and the native isolated Paenibacillus sp. A224 disease decreased and plant biomass increased compared to control plants inoculated only with microsymbiont, challenged with S. rolfsii and exposed to 35 °C for 6 days. Furthermore, we found that bacterial metabolites secreted to culture medium were unable to protect plants from these stresses. We also determined that a foliar application of A224 at the beginning of colonization of the pathogen does not increase synergistically the plant tolerance. Regarding symbiosis, none of the isolates tested reversed the deleterious effect caused by the simultaneous stresses.In conclusion, A224, in co-inoculation with the peanut microsymbiont, would be able to mitigate the simultaneous stresses caused by high temperatures and S. rolfsii on the growth and health of plants when is inoculated in peanut radicles.