PGPRs of plum (Prunus domestica) rhizosphere enhance plant growth and antagonise fungal activity in vitro

摘要

Plant growth promoting rhizobacteria (PGPR) promote the plant growth by various direct and indirect mechanisms. The present study was undertaken to isolate and characterise the PGPRs of plum (Prunus domestica) rhizosphere in Pakistan. A total of 95 rhizobacteria were isolated, out of which 40 strains were selected on the basis of morphological, biochemical and Gram staining characteristics. The selected isolates were screened for in vitro plant growth promoting potential and were subsequently evaluated for host plant growth promotion. The selected isolates demonstrated strong lytic enzymatic activities and were able to produce ammonia, siderophore, Hydrogen cyanide along with capability of phosphate solubilisation. Moreover, the results showed a significant growth suppression of pathogenic Fusarium oxysporum and Rhizoctonia solani in an in vitro assay. The plant microbe interaction study was carried out using 11 most efficient rhizobacterial strains inoculated to roots of plum plants. The inoculated PGPRs significantly augmented the leaves number per shoot, shoot diameter, shoot length and plant height. The inoculation also significantly increased the chlorophyll contents of leaves, concentration of micro and macro nutrients compared with control. The current study shows the importance of these selected PGPRs as bio-fertilizer to improve the health and productivity of plum species in Pakistan.