BIODIVERSITY OF HALOPHYTES IN NORTH SINAI ENVIRONMENTS

Abstract

The diversity of culturable bacteria associated to the salt-affected plants cover of Mediterranean Sea-affected areas of Egypt was investigated. Ecto- and endo-rhizospheres as well as phyllospheres of tested plants accommodated dense populations of culturable halotolerant bacteria recovered on various salted culture media. From the Lake Bardawil of North Sinai, eleven bacterial isolates were obtained, and their morpho-physiological characterization confirmed their belonging to the genera Bacillus spp., Enterobacter spp. Pantoea spp. Pasteurella spp. and Vibrio spp. The majority of isolates exhibited plant growth promoting (PGP) abilities, e.g. N2-fixation, P-solubilization, and NaCl tolerance up to 10%. The plant-based-sea water culture medium is successfully introduced to in vitro cultivation and in situ recovery of associated halophlic microbiome. The ice plant (Mesembryanthemum crystallinum) was used, in the form of juice and/or dehydrated plant powder packed in teabags, to supplement the natural sea water. The culture medium, as such without any supplements, supported very good in vitro growth of halophlic bacterial isolates. It was also capable to recover the culturable population of bacteria associated to halophytes prevailing in Lake Mariout, Alexandria. When related to the total bacterial numbers, associated the plant roots of Suaeda pruinosa, as measured by quantitative-PCR, the culture medium supported significant increases in culturability of halophytes (15.3-19.5 %) when compared to the conventional chemically-synthetic culture medium supplemented with (11.2%) or without (3.8%) NaCl. Based on 16s rDNA sequencing, representative isolates prevailed on such culture medium were closely related toBacillus spp., Halomonas spp., and Kocuria spp.. Seed germination tests on 25-50% sea water agar, indicated positive interaction of those bacterial isolates with the germination and seedlings’ growth of barley seeds.