Bioprospecting in Colombian hydrophytes for bacteria with biocontrol potential against Fusarium root rot of tomato and spoilage of fresh shrimp

Microbial pathogens pose major challenges to agricultural productivity and food preservation, demanding their elimination or control. This study explored the biocontrol potential of endophytic and rhizospheric bacteria isolated from 27 different species of wild hydrophytic plants sampled in four different Colombian habitats; a mountain river, a mangrove swamp, a cloud forest and a freshwater lagoon. This work is the first time anyone has studied the microbiomes of plants in the genera Marathrum, Matisia, Myriocarpa, Rhodospatha , and Sclerocarpus or the bacterial endophytes in Miconia, Saurauia, Sanicula , and Renealmia . A total of 418 strains were isolated, spanning 49 genera, with the family Bacillaceae predominating. Four endophytic strains isolated from cloud forest plants— Neobacillus bataviensis, Paenibacillus lupini, Peribacillus simplex , and Gottfriedia endophytica —exhibited strong antagonism against Fusarium oxysporum , both in vitro on Petri dishes and in vivo during tomato plant infection assays, significantly reducing fungal DNA concentration, eliminating wilt symptoms and restoring plant vigor. Additionally, 38 isolates showed inhibitory activity against Salmonella , Listeria and/or Staphylococcus , and the most effective of these was identified as Aeromonas dhakensis which significantly inhibited growth of S. auereus and reduced the pH increase in raw shrimp stored at 8°C for two weeks. Further strain characterization and functional validation under real world conditions may allow the development of live cell or shelf-stable endospore-based inoculants for biocontrol applications in plant agriculture, however due to biosafety concerns, preservative products for seafood derived from bacterial endophytes are more likely to be developed on the basis of their purified bioactive molecules (eg. bacteriocins).