Endophytic bacterial communities of alpine Rosaceae plants are affected by the plant tissue, collection site and host plant and culturable psychrotolerant isolates contribute to plant freezing stress tolerance

Summary Wild plants growing in alpine regions are associated with endophytic microbial communities that may support plant growth and survival under cold conditions. The structure and function of endophytic bacterial communities were characterised in flowers, leaves and roots of three alpine Rosaceous plants in Alpine areas using a combined amplicon sequencing and culture-dependent approach to identify factors shaping these communities. Amplicon-sequencing analysis revealed that plant tissue, collection site and host plant are the main factors affecting the richness, diversity and taxonomic structure of endophytic bacterial communities in alpine Rosaceae plants. Core endophytic bacterial taxa were identified as 31 amplicon sequence variants highly prevalent across all plant tissues. Psychrotolerant bacterial endophytes belonging to the core taxa of Duganella, Erwinia, Pseudomonas and Rhizobium genera mitigated freezing stress in strawberry plants, demonstrating the beneficial role of endophytic bacterial communities and their potential use for cold stress mitigation in agriculture.