Author(s)

F. Y. Hafeez & M. N. Hassan

Abstract

Plant associated bacteria are beneficial microbes which inhabit various parts of plants such as rhizosphere, endosphere and polysphere. These small little wonders improve plant health either directly by providing nutrients or indirectly by suppressing disease causing pathogens. We isolated more than 1000 rhizobacteria from the rhizosphere and endosphere of various field crops and screened for biofertilizer and biopesticide characteristics. About 100 isolates were selected on the basis of best N-fixation (3624 nmole C2H4/mg protein/h), P-solubilization (320 μg /mL), Silicate solubilization (35 mm zone), Indole acetic acid production (62 μg /mL), and in vivo biocontrol activity (30-60%) under field conditions. These effective PGPR belonged to different genera such as Acetobacter, Pseudomonas, Azospirillum, Rhizobium, Azotobacter, Bacillus, Enterobacter, Aeromonas, Burkholderia and Serratia as identified by 16S rDNA. Biocontrol activity of the antagonistic strains was found to be associated with the production of siderophores, antibiotics such as surfactin, pyoluteorin and hydrolytic enzymes like protease, glucanase and chitinase. The potent strains were preserved at Pakistan Collection of Microbial Cells (PCMC). The some efficient strains capable to solubilize phosphorus and survive in humic acid with a population of 107-108 CFU g-1 until six months have been formulated as biofertilizers with the trade name HumiphosTM and BiophosTM in collaboration with Auriga Chemical Enterprises, Lahore, Pakistan. These biofertilizers saved 50% chemical phosphatic fertilizer and increased the yield up to 10-20% of different field crops such as wheat, rice, potato, cotton, maize and vegetables.

Keywords

PGPR, diazotrophs, macronutrients, micronutrients, pathogens, biopesticide, Bio power, Humiphos, Biophos, commercialisation