oa Metagenomic Approach to Explore Microbial Communities in the Rhizosphere of Date Palm

Microbial communities in the date palm rhizoshere can play a vital role in the development of the palm and its health. Using the metagenomic as a tool can help in exploring these microbial communities in searching for microorganisms with potential for agricultural practices.

Samples (roots and soil) were collected for metagenomic analysis from 12 date palms (khalas cv) growing at Roudat Alfars Research Farm of the Ministry of Environment. Sampling were done for the second time three month after fertilization of the palms. DNA was extracted and PCR were carried out for the variable regoins v1-v3 of the 16S rRNA gene. The amplified fragment were sequences using Next-Generation Sequencing (NGS) in two directing. Assembly of the reads and analysis were done Using mothur software Version 1.36.1.

Results showed the presence of 13 bacterial phyla. Fertilizer has positive effect on increasing the presence of most of these phyla. A strong presence of cyanobacteria were observed followed by Proteobacteria then Actinobacteria in most samples. Cyanobacteria showed dramatic increased (in some samples more than 60 %) after fertilization. Cyanobacteria is known of their potential for atmospheric nitrogen fixation to ammonia (NH3), nitrite (NO2) or nitrates (NO3). Such process can act as an additional source of nitrogen for date palms.

Also the analysis reviles the presence of Arthrobacter which is one of the main components of the soil microbes. It has the potential to reduce hexavalent chromium level in contaminated soil as well as degrades the 4-chlrophenol. Further investigation is needed to assess their potential as biodegradation agent.

The following step is to isolate and characterize these bacteria as well repeating the metagenomics analysis after one year to determine the persistence of these microbial communities in the date palm orchard.