Properties of the halophyte microbiome and their implications for plant salt tolerance

Saline habitats cover a wide area of our planet and halophytes (plants growing naturally in saline soils) are increasingly used for human benefits. Beside their genetic and physiological adaptations to salt, complex ecological processes affect the salinity tolerance of halophytes. Hence, prokaryotes and fungi inhabiting roots and leaves can contribute significantly to plant performance. Members of the two prokaryotic domains Bacteria and Archaea, as well as of the fungal kingdom are known to be able to adapt to a range of changes in external osmolarity. Shifts in the microbial community composition with increasing soil salinity have been suggested and research in functional interactions between plants and micro-organisms contributing to salt stress tolerance is gaining interest. Among others, microbial biosynthesis of polymers, exopolysaccharides, phytohormones and phytohormones-degrading enzymes could be involved.