Plant growth promoting rhizobacteria (PGPR) play an important role for improving plant growth and increasing
productivity especially under stress condition. Fifty rhizobacterial isolates were isolated from the rhizosphere of the
wheat plants. The rhizobacterial isolates were screened to select the most salt tolerant isolates. Then, the more tolerant
isolates were evaluated for plant growth promoting activities such as ammonia, HCN, siderophores, nitrogenase,
indole acetic acid (IAA) and gibberellins (GB) production as well as, root colonization ability, phosphate and
potassium solubilization. The obtained data showed that, rhizobacterial isolate number (40) exhibited high records for
most of PGPR activitiesand identified asPaenibacillus polymyxaMG309677.1using 16S rRNA gene sequencing
techniques with 99% similarity. One of the problems which face production of microbial preparations for agriculture
use is the maintenance of bacterial viability. In this respect, immobilization of P. Polymyxa MG309677.1 on three
different carriers (peatmoss, compost and sawdust) was studied. Peatmoss and compost were used singly or combined
with sawdust at two levels (50% and 75% sawdust).Bacterial populations, dehydrogenase activity, pH values and
moisture contents were determined monthly up to six months of storage. Resultsrevealed that, using of peat moss
either singly or combined with sawdust (50:50%) as a carrier gave the highest survival and population records forP.
polymyxaMG309677.1even the end of storage period (180) days. |
