Developing PGPR consortia using novel genera Providencia and Alcaligenes along with cyanobacteria for wheat

A pot experiment was undertaken using unsterile soil supplemented with the recommended dose of chemical fertilizers in order to investigate the effect of indole-3-acetic acid (IAA)-producing proteo- and cyanobacterial strains on the growth and yield of wheat (Triticum aestivum variety PBW343). Two proteobacterial (WRB4 Providencia sp. and WRB10 Alcaligenes sp.) and two cyanobacterial (WRC3 Anabaena oscillarioides and WRC4 Anabaena torulosa) strains were used individually and in combination. The treatment in which proteobacteriumWRB4 (Providencia sp.) was inoculated showed significantly higher values in comparison with controls for various plant-growth parameters recorded, i.e. shoot length, root length, shoot weight, root weight and crop biomass, followed by the treatment in which the WRC3 (Anabaena oscillarioides) was used. A positive interaction among the proteo- and cyanobacterial strains, in particular WRC3 and WRB4, was also observed by way of enhancement of plant-growth parameters. Significant enhancement in soil microbiological activities such as fluorescein diacetate (FDA) hydrolysis and dehydrogenase activity were recorded in the treatments, particularly in those inoculated with cyanobacterial strains, when compared with fertilizer controls. This is a first-time report on the potential of selected combinations of proteobacterial genera such as Providencia and Alcaligenes and cyanobacteria such as Anabaena as plant growth-promoting organisms in wheat crop.