Pantoea and Pseudomonas two endophytes that colonize the surface and the tissue of tomato antagonize plant pathogens by secreting organic compounds.

LÓPEZ, SILVINA M. Y.; GRACIELA N. PASTORINO; VIRGINIA MARTÍNEZ ALCÁNTARA; JUAN MANUEL REPARAZ; BALATTI, PEDRO A.

Pittsburgh, Pennsylvania

Congreso; Plant Health 2022; 2022

The American Phytopathological Society (APS)

Pantoea and Pseudomonas two endophytes that colonize the surface and the tissue of tomato antagonize plant pathogens by secreting organic compounds.Endophytic bacteria of tomato microbiome protect plants by secreting antimicrobial compounds. We want to understand the ways these bacteria protect tomato plants. We studied two species Pantoea sp. and Pseudomonas sp. we made gfp mutants to study their distribution as well as their way of entry to the plants. Both wild type and mutants inhibited growth of fungal pathogens. These two species synthetize soluble as well as volatile organic compounds (VOCs) that prevented fungal growth. The sterile supernatant of Pantoea sp. inhibited growth of Alternaria alternata, Corynespora cassiicola y Stemphylium lycopersiciby 45 %, 22 % and 1 %, respectively. Both bacterial species released VOCs reducing fungal growth at least by 50%. While Pantoea, synthetized several alcohols among them 3-Metil Butanol was the most important one. Pseudomonas, synthetized alcohols but also ketones, the most abundant was x-undecane. Both bacteria successfully colonized tomato roots and as expected they adhered to the seeds, radicles, stems and cotyledons and also entered the tissues. UFC resistant to tetracycline only were recovered from inoculated plants. Total as well as endophytic bacterial numbers were higher in inoculated plants. The understanding of the early events of bacterial entry in tomato plants requires additional experiments. In conclusion bacterial endophytes of tomato might be increased by inoculation leading this to the colonization of different plant organs which might modify the interactions of plants with pathogens.