Diversity of bacteria nesting the plant cover of north Sinai deserts, Egypt

Abstract

North Sinai deserts were surveyed for the predominant plant cover and for the culturable bacteria nesting their roots and shoots. Among 43 plant species reported, 13 are perennial (e.g. Fagonia spp., Pancratium spp.) and 30 annuals (e.g. Bromus spp., Erodium spp.). Eleven species possessed rhizo-sheath, e.g. Cyperus capitatus, Panicum turgidum and Trisetaria koelerioides. Microbiological analyses demonstrated: the great diversity and richness of associated culturable bacteria, in particular nitrogen-fixing bacteria (diazotrophs); the majority of bacterial residents were of true and/or putative diazotrophic nature; the bacterial populations followed an increasing density gradient towards the root surfaces; sizeable populations were able to reside inside the root (endorhizosphere) and shoot (endophyllosphere) tissues. Three hundred bacterial isolates were secured from studied spheres. The majority of nitrogen-fixing bacilli isolates belonged to Bacillus megaterium,Bacillus pumilus, Bacillus polymexa,Bacillus macerans,Bacillus circulans and Bacillus licheniformis. The family Enterobacteriaceae represented by Enterobacter agglomerans,Enterobacter sackazakii, Enterobacter cloacae, Serratia adorifera,Serratia liquefaciens and Klebsiella oxytoca. The non-Enterobacteriaceae population was rich in Pantoae spp., Agrobacterium rdiobacter, Pseudomonas vesicularis, Pseudomonas putida, Stenotrophomonas maltophilia, Ochrobactrum anthropi, Sphingomonas paucimobilis and Chrysemonas luteola.Gluconacetobacter diazotrophicus were reported inside root and shoot tissues of a number of tested plants. The dense bacterial populations reported speak well to the very possible significant role played by the endophytic bacterial populations in the survival, in respect of nutrition and health, of existing plants. Such groups of diazotrophs are good candidates, as bio-preparates, to support the growth of future field crops grown in deserts of north Sinai and irrigated by the water of El-Salam canal.

Cultivation-Based and Molecular Assessment of Bacterial Diversity in the Rhizosheath of Wheat under Different Crop Rotations

“…Rhizosheaths act as an additional compartment in the rhizosphere of plants, being chemically and physically enriched and subsequently nourishing functional populations of microorganisms. Largely based on cultivation studies, rhizosheaths have been shown to harbour a range of different bacteria including members of the genera Bacillus , Paenibacillus , Enterobacter and Agrobacterium [ 11 ], [ 12 ].…”

Identification and validation of reference genes to study the gene expression in Gluconacetobacter diazotrophicus grown in different carbon sources using RT-qPCR

“…G. diazotrophicus has been mainly found colonizing plants such as Pennisetum purpureum Schum (Reis et al, 1994;Baldani et al, 1997), Ipomea batatas Lamb (Paula et al, 1991), Coffea arabica L (Jimenez-Salgado et al, 1997), Ananas comosus L. (Tapia-Hernández et al, 2000), Polycarpon succulentum L., Fagonia arabica L., and Malva parviflora L. (Madhaiyan et al, 2004). Recently, the existence of G. diazotrophicus was reported in the rhizo-and-phyllo spheres of a number of desert plants in Sinai environment (Hanna et al, 2012). This bacteria species is capable of oxidizing ethanol to acetic acid, tolerate high concentrations of glucose (Kesters et al, 2006;Nakano and Fukaya, 2008) and to convert N 2 to NH 3 through biological nitrogen fixation (Cavalcante and Dobereiner, 1988;Kim and Rees, 1994).…”

The Plant Host Induces Antibiotic Production To Select the Most-Beneficial Colonizers

“…Eruca sativa (salad rocket) is a winter annual undomesticated wild flowering plant that grows in nature mostly around the Mediterranean basin (50). It belongs to the Brassicaceae family, which includes various natural plant hosts for both Bacillus and Serratia species (51).…”