DIVERSITY OF CULTIVABLE ENDOPHYTIC BACTERIA ASSOCIATED WITH BLUEBERRY PLANTS (Vaccinium corymbosum L.) cv. Biloxi WITH PLANT GROWTH-PROMOTING TRAITS.

Abstract

he present work explores the diversity of cultivable endophytic bacteria associated with blueberry plants (Vaccinium corymbosum L.) cv. Biloxi, and characterizes their plant growth promoting activities, including the production of indoleacetic acid (AIA), biofilm, siderophores and proteolytic activity. Bacterial endophytes were isolated from different tissues of blueberry plants. A higher population density of endophytic bacteria was obtained from roots compared stems and leaves. BLAST and phylogenetic analysis, based on 16S ribosomal gene sequencing, showed the identification of 24 bacterial species distributed in 4 Phyla, such as Bacteroidetes (1.1%), Actinobacteria (23.9%), Firmicutes (12.5%) and Proteobacteria (62.5%). The most abundant genera were Pantoea, Pseudomonas, Burkholderia and Bacillus, among others. When analyzing some plant growth-promoting activities, 42% of the endophyte isolates showed at least one beneficial activity. Interestingly, some strains of Bacillus and Pantoea showed better production of phytohormones (AIA), biofilm and siderophores compared to the well-known PGPR Pseudomonas fluorescens UM270. These results show that the bacterial endophytes could play a beneficial role in blueberry plants, and be potentially used as bioinoculants in other crops of agricultural importance.