Exploration of Plant and Microbial Life at "El Chichonal" Volcano with a Sustainable Agriculture Prospection.

Active volcanic environments represent extreme habitats with underexplored potential for microbial bioprospecting. This study aimed to characterize pioneer vegetation and associated microbial diversity in the crater of "El Chichonal" volcano, with an emphasis on their potential applications in sustainable agriculture. A physicochemical analysis of the soil was performed, identifying acidic and nutrient-poor conditions. Three pioneer plant species were described: Tibouchina longifolia (dominant) and Poaceae spp. (co-dominant), and Palhinhaea cernua (non-dominant). A total of 311 microorganisms were predominantly bacteria, were isolated from soil, root, stem, and water samples. Bacillus cereus and Priestia megaterium were molecularly identified, and in vitro assays demonstrated their ability to fix nitrogen, produce auxins, and antagonize fungal pathogens (Alternaria solani, Botrytis cinerea, and Colletotrichum gloeosporioides). These results suggest that microorganisms adapted to extreme volcanic environments could be promising sources of plant growth-promoting bacteria (PGPB) with application in biological control.