The root growth of wheat plants, the water conservation and fertility status of sandy soils influenced by plant growth promoting rhizobacteria Naeem Khan 1 & Asghari Bano 1 & MD Ali Babar 2 Received: 14 June 2016 /Accepted: 17 October 2016 # Springer Science+Business Media Dordrecht 2016 Abstract Plant growth promoting rhizobacteria were isolated and characterized from sandy soils in Pakistan. The role of the rhizobacteria, in association with plant growth regulators, was studied on the roots of wheat grown under water stressed conditions. The plant growth promoting rhizobacteria were characterized on the basis of colony morphology, biochemical traits and identified on the basis of 16S-rRNA gene sequenc- ing which identified the selected isolates Planomicrobium chinense, Bacillus cereus and Pseudomonas fluorescens. Antibacterial and antifungal activities were determined. The fresh cultures (24 h old) of isolates were used to soak the seeds for 2–3 h prior to sowing. The growth regulators salicylic acid and putrescine were applied to the plant as foliar spray at three leaf stage. The plant growth promoting rhizobacteria produced exopolysaccharides that formed soil aggregation around roots of the plants and significantly enhanced water holding capac- ity of sandy soil. The relative water content (80%) of leaves and root fresh (80%) and dry weight (68%) were higher in plant growth promoting rhizobacteria inoculated plants. The nutrient content of rhizosphere soil of treated plants was also enhanced (Ca 35%, K 34%, Mg 52% and Na 42%) over stressed controls. Integrative use of effective plant growth promoting rhizobacteria in combination with salicylic acid appears to be an effective eco-friendly approach to increase drought tolerance in wheat plants to combat desertification. Keywords EPS . Plant growth promoting rhizobacteria . Sandy soil . 16S-rRNA gene sequencing 1 Introduction Plant growth-promoting rhizobacteria stimulate health and productivity of plants by the solubilisation of minerals, promoting root growth and suppressing root diseases. The predominant belong to Azospirillum, Bacillus, Pseudomonas, and Agrobacterium (Khan and Bano 2016a; Viveros et al. 2010). Plant roots exude a variety of nutrients, organic compounds, and signals that attract microbial populations (Bais et al. 2006; Drogue et al. 2012; Pothier et al. 2007; Shukla et al. 2011). The resul- tant bacterial community associated with the plant roots has been termed the rhizo-microbiome (Chaparro et al. 2013). Its composition is different from the microbes found in the adjacent soil (Bulgarelli et al. 2013 ; Chaparro et al. 2013; Raynaud et al. 2008). Since the root exudates vary in relation to the root development stage and plant genotypes, the rhizo-microbiome also fluctuates (Aira et al. 2010; Berg and Smalla 2009; Bouffaud et al. 2012; Bulgarelli et al. 2013; Chaparro et al. 2013). These rhizobacteria have been shown to increase root growth that leads to a system with a larger surface area and enhanced number of root hairs (Mantelin and Touraine 2004). Nutrients and water are taken up by plants through the rhizo-sheaths; the soil stuck firmly to the crop roots (McCully and Canny 1988; Watt et al. 1994) that deliver a carbon supply to the microbial community involved in cycling minerals to the growing plants (Nannipieri et al. 2003 ). Rhizo-sheath formation involves exopolysaccharides (EPS) (Czarnes et al. 2000). These polymers are produced and released by soil micro- * Asghari Bano banoasghari@gmail.com 1 Phytohormone lab, Department of Plant Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan 2 Agronomy Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL, USA Symbiosis DOI 10.1007/s13199-016-0457-0