Exploring the potential of native bacteria for strawberry plant growth promotion

Strawberry production is challenged by several biotic and abiotic stresses, such as angular leaf spot (ALS) disease caused by Xanthomonas fragariae, and high soil salinity and drought. In the last decades, the development of commercial products containing combinations of different plant growth promoting (PGP) microorganisms has been one of the main focuses of agricultural research. However, their efficacy could be hindered by competition or incompatibility occurring among different strains or with indigenous plant microbiota. The application of beneficial microorganisms on the same host species from which they were isolated might increase their positive effect, promoting their use for a sustainable agriculture. In this work, native bacteria isolated from different strawberry cultivars were screened for their PGP abilities, and applied to plants in both normal and stressor (X. fragariae infection and salinity) conditions. The monitoring of the biometric parameters of inoculated strawberry plants allowed the selection of a restricted group of bacteria (Pseudomonas fluorescens m27, Stenotrophomonas rhizophila m23, Agrobacterium rubi m39), whose application showed a significant increase of plant growth performances and resistance to stress. Future experiments will aim at simultaneously inoculate selected strains on different plant organs and at understanding the complex mechanisms influencing plant-microbes and microbes-microbes networks.