Plant genetics and site properties influenced the diversity of seed endophytic bacterial communities of Odontarrhena species from serpentine soil of Albania.

Aims: Seed endophytic bacteria (SEB) are able to improve plant growth and to protect them against abiotic or biotic stresses. This work aimed to characterize the seed endophytic bacterial communities associated with different species of the nickel hyperaccumulator Odontarrhena, which is adapted to extreme environments such as serpentine soils. Moreover, this work also aimed to study any potential congruency between SEB community diversity and plant phylogeny. Methods: Endophytic bacterial communities were characterized for seeds from 9 Odontarrhena populations, using high throughput sequencing. The plant genomes and environmental properties of the sites had previously been described. Results and discussion: All Odontarrhena populations shared more than 95% of their OTUs and metabarcoding revealed a large SEB core microbiome. The plant species was more determinant than the site in explaining the dissimilarities between SEB communities. Nonetheless, both site and Odontarrhena species factors were significant diversity drivers of the SEB communities and the best explanatory factor was the interaction between them. When focusing only on plant populations, some OTUs were over- or under-represented in the O. chalcidica SEB communities in comparison with the SEB communities of the 4 other Odontarrhena species. With the current genetic markers, the cophylogenetic analysis revealed a non-significant coherence of phylogenies between seed microbiota and corresponding host plants. The OTUs based prediction of metabolic functions, is a first step that would potentially allow the power of the microbiome to be harnessed, thereby improving hyperaccumulator production in an agromining context. [ABSTRACT FROM AUTHOR]