Metabolic and biofungicidal properties of maize rhizobacteria for growth promotion and plant disease resistance

Abstract

Plant growth promoting rhizobacteria (PGPR) are known to influence plant growing both by direct and/or indirect mechanisms. This study aimed to establish PGPR profile of 15 bacteria isolated from maize (Zea mays L.) rhizosphere in Benin. These rhizobacteria were screened in vitro for the  plant growth promoting traits like production of indole acetic acid (IAA), ammonia (NH3), hydrogen cyanide (HCN), catalase, exopolysaccharides and antifungal activity against phytopathogenic fungi for example Fusarium verticillioides, that is an important maize pathogenic. Most rhizobacteria strains were found to produce catalase (100%), exopolysaccharides (100%), ammonia (86.66%), hydrogen cyanide (80%) and indole acetic acid (60%). Pseudomonas putida, Pseudomonas fluorescens and Azospirillum lipoferum have highly produced many of the investigated metabolites. Streptomyces  hygroscopicus, Streptomyces  fasciculatus, Pseudomonas aeruginosa, P. putida, P. fluorescens and A. lipoferum inhibited mycelial growth of F. verticillioides and Aspergillus ochraceus. P. fluorescens and P. aeruginosa were highly antagonistic against F. verticillioides (52.24% of mycelial growth inhibition) and A. ochraceus (58.33% of mycelial growth inhibition). These results suggest the possibility to use these rhizobacteria as biological fertilization to increase maize yield and the biological control of F. verticillioides and A. ochraceus.
 
Key words: Rhizobacteria, Plant growth promoting rhizobacteria (PGPR), antifungal activities, biological control, Benin.