Selection of indigenous fluorescent pseudomonad isolates from maize rhizospheric soil in Vojvodina as possible PGPR

Abstract

Among 268 bacterial isolates obtained from maize rhizospheric soil from Novi Sad, Vojvodina, Serbia, 59 were fluorescent pseudomonads. According to intrinsic antibiotic resistance (IAR) and heavy metal tolerance (HMT) patterns, the six representative isolates were selected and their diversity was assessed. Lytic enzyme activity (protease, chitinase, lipase, phospolipase, cellulase, gellatinase, pectinase, urease), plant-growth promoting treats (P-solubilization, siderophores, HCN and IAA production) and plant pathogenicity estimation (on lilac leaf, apple and bean pods) resulted in selection of three isolates (PS2, PS4, PS6) with the outlook for agriculture application. Antifungal activity was estimated on dual culture with eight phytopathogenic fungi (Curvularia lunata, Fusarium semitectum, Fusarium equiseti from Salvia officinalis L., F.equiseti from Matricaria chamomilla L., Myrothecium verrucaria, Verticillium sp., Diaporte eres complex and Sclerotinia sclerotiorum) isolated from medicinal plants in Serbia. Isolate PS2 showed hyphal deformation of all investigated fungi and effective inhibition of mycelial growth of 7 out of 8 phytopatogenic fungi, partly due to production of chitinases, siderpohores and lytic enzymes. Abundant production of IAA (14 to 37 mM) and siderophores, phosphate solubilization and especially fungal growth inhibition make it suitable for further investigation, field trials and possible application in maize cultivation as biocontrol agent. © 2011 University of Bucharest.