EXPLORING POTENTIAL OF METAL RESISTANT AND PGP ATTRIBUTES OF PHOSPHATE SOLUBILIZING RHIZOBACTERIA ISOLATED FROM SOUTHERN PUNJAB, PAKISTAN

Abstract

Phosphorus is highly required nutrient for proper plant functioning and growth but due to its highly reactive nature it changed its form after short period of time when we applied as fertilizer and become unavailable for plant uptake while Phosphate solubilizing rhizobacteria are powerful candidates that solubilize the P that is already present in soil. So, the present research based on the hypothesis to isolating, screening and optimizing the phosphate solubilizing rhizobacteria with potential of metal
resistant and multiple PGPR attributes. Total 55 PSR strains were isolated out of which 20 strains (WUSB1,WUSB2, WUSB3, WUSB4, WUSB5, WUSB6, WUSB7, WUSB8, WUSB9, WUSB10, WUSB11, WUSB12, WUSB13, WUSB14, WUSB15, WUSB16, WUSB17, WUSB18, WUSB19, WUSB20) were selected with 4-8 (PSI) and 30-122?g/ml phosphate solubilization in NBRIP medium for one week
incubation at 370C. These strains were further analyzed for their physiochemical attributes, metal resistant, extracellular enzyme production and PGP attributes. Final results showed that one candidate designated the name as WUSB16 produce significant results i.e. having capacity to solubilize P 5.46 (PSI) on agar plate assay and 105?g/ml in broth assay, Acid and alkaline phosphatase production 20?mol PNPb ml-1 hr-1 or 15?mol PNP ml-1 hr-1 respectively. It showed metal resistant against ZnSO4, MnSO4 and CuSO4. Evaluation of PGP attributes indicated that the capacity of WUSB16 strain for auxin production was 100?g/ml, for siderophore and nitrogen fixation was stronger (+++), for Hydrogen Cyanide and ammonia production was medium (++) and for ACC deaminase was negative (-). From above results we can conclude that WUSB16 PSR strain with multifaceted PGP traits is the best candidate that have potential to utilized as Phosphate solubilizing bioinoculant.