Genomic and Metabolomic Insights into Secondary Metabolites of the Novel Hil4, an Endophyte with Promising Antagonistic Activity against Gray Mold and Plant Growth Promoting Potential.

The endophytic bacterial strain Hil4 was isolated from leaves of the medicinal plant . It exhibited antifungal activity against and a plethora of plant growth promoting traits in vitro. Whole genome sequencing revealed that it belongs to and possesses numerous secondary metabolite biosynthetic gene clusters and genes involved in plant growth promotion, colonization, and plant defense elicitation. The Mojavensin cluster was present in the genome, making this strain novel among plant-associated strains. Extracts of secreted agar-diffusible compounds from single culture secretome extracts and dual cultures with were bioactive and had the same antifungal pattern on TLC plates after bioautography. UHPLC-HRMS analysis of the single culture secretome extract putatively annotated the consecutively produced antimicrobial substances and ISR elicitors. The isolate also proved efficient in minimizing the severity of gray mold post-harvest disease on table grape berries, as well as cherry tomatoes. Finally, it positively influenced the growth of Col-0 and var. Chondrokatsari Messinias after seed biopriming in vitro. Overall, these results indicate that the strain Hil4 is a promising novel plant growth promoting and biocontrol agent, and can be used in future research for the development of biostimulants and/or biological control agents.