Seed-endophytes empower Anthemis cotula to expand in invaded range

The seeds serve as a biological vehicle for alien species to colonize new habitats and seed endophytes may enhance their chances of survival and spread in the introduced range. Thus, the endophytic diversity associated with the seeds of alien species and their plant growth-promoting activities need to be investigated in detail. Here we explored the composition and diversity of culturable endophytic microbes inhabiting achenes of Anthemis cotula L. an invasive alien species in Kashmir Himalaya. A total of 812 culturable endophytic isolates were recovered from seeds of A. cotula, comprising 716 bacterial isolates, and 96 fungal isolates. Taxonomic binning resolved the isolates into 39 bacterial OTUs and 22 fungal OTUs belonging to 4 bacterial phyla and 2 fungal phyla. The relative abundance of these culturable seed endophytic taxa differed significantly across the sites (p < 0.001). Moreover, similar endophytic communities with a shared core endophytic assemblage were observed across different sites. This core microbiome was represented by 17 bacterial and 8 fungal OTUs. We also screened the isolated endophytes for various plant growth-promoting activities, such as IAA production, phosphate solubilization, and ammonia production and more than 75% of the isolates showed one or the other plant growth-promoting activity, Interestingly, some isolates showed strong antagonistic activity against Botrytis cinerea which is a common pathogen of A. cotula in its native range. Given the functional attributes of achene borne endophytes, their role in the establishment and spread of A. cotula in Kashmir Himalaya is quite likely and plausible