A consortium of cyanobacteria and plant growth promoting rhizobacteria for wheat growth improvement in a hydroponic system

Biofertilizers containing living organisms are attractive because of their potential positive impact on plant growth and reduced environmental effect compared to mineral fertilizers. Many studies have reported the potential of plant growth-promoting rhizobacteria (PGPR) and cyanobacteria, applied singly or in combination. In the present study, the combined effect of PGPR and cyanobacteria on Triticum aestivum L. was examined in a hydroponic growth system. Calothrix sp. and Anabaena cylindrica were used as cyanobacterial strains, and Chryseobacterium balustinum, Pseudomonas simiae and Pseudomonas fluorescens were used as PGPR strains. In addition to growth parameters, total nutrients in each treatment and the ability to produce indole acetic acid (IAA) were measured after 17 days of treatments. The study results indicate that the consortium of the five isolates gave the best performance in terms of growth parameters. It increased by 36% for plant height in the combination of Calothrix sp. and P. simiae, and the dry shoot mass was increased by 80%, 77%, and 76% under the combinations of A. cylindrica with C. balustinum, P. simiae, and P. fluorescens, respectively. The ability to produce IAA was confirmed in the treatments with cyanobacteria, with PGPR strains, and in treatments combining the different microorganisms, using both colorimetric and chromatographic methods. Thus, biofertilizers containing the consortia cyanobacteria and PGPR used in this study are recommended for improved growth of wheat plants.This work was financed by LIFE13 ENV/ES/001251 EU Project. Rajaa Kholssi benefits from a grant of the AECID (Foreign Office of Spanish Government)