ISOLATION AND IDENTIFICATION OF RHIZOBACTERIA FROM MAIZE (ZEA MAYS L.) IN LUVISOLS AND DOCUMENTATION THEIR PLANT GROWTH PROMOTING TRAITS

Abstract

There is a growing interest in the issue of inoculation of rhizobacteria into the agricultural soil because this group of bacteria can  increase  productivity and quality of  agriculturally important crop and contributes to the stability of agroecosystems. The aim of our work was to isolate and characterize of plant growth promoting traits (production of IAA, siderophores, phosphate solubilisation, antifungal activity) of rhizobacteria belonging to a group of plant growth promoting rhizobacteria (PGPR), and isolated from rhizosphere of maize (Zea mays L.) in luvisols.  Quantitative representation of rhizobacteria of maize was 7.4 . 10⁶ CFU.g^-1 dry soil. A total of eleven species of maize rhizosphere where isolated and confirmed as PGPR in vitro. The  all  isolates  showed positive indole-3-acetic acid (IAA) production ranging between 1.39 and 15.74 µg.ml^-1. Seven  strains (63.6  %) has been shown with low and 1 strain with intermediate solubilisation index of phosphates and the  positive production of siderophores showed  7 isolates (63, 6 %). Except for the isolate KmiJP17B089, all others inhibited the growth of Sclerotinia sclerotiorum and Rhizoctonia solani by more than 50 %. In the case of Fusarium graminearum, on the other hand, we observed a very low inhibitory activity. The most active  in observed traits were  three isolates identified by the 16S rRNA gene sequencing and NCBI database using the BLAST  resource as Bacillus altitudinis strain KmiJP17B089, Bacillus aryabhattai strain KmiJP17B090  and  Bacillus megaterium strain KmiJP17B091. These results suggest the possibility to tested in vivo these Bacillus species as potential biological fertilizer  to increase maize production.