Molecular Identification of Potential Rhizobacteria Isolated from Maize (Zea mays L.)

Abstract

Maize (Zea mays L.) is one of the highly demanding food plants in Indonesia but the production is currently not sufficient to meet the community's needs, so that efforts to import maize in Indonesia are still frequently carried out. Meanwhile, the maize production who mostly produced by local farmer mainly cultivated on marginal land which is threatened by drought stress. Efforts should be make to increase maize productivity on dry land by utilization of rhizobacteria isolated from maize rhizosphere. This study aimed to determine the types of rhizobacteria from the diversity of microbes that potentially increase the productivity of maize plants. This study used 2 isolation methods, namely isolation on gram-positive and gram-negative, followed by electrophoresis and PCR with primers of 27F and 1492R. Then the PCR results were sequenced and analyzed using Mega X. The sequencing results compared with Genbank at NCBI showed 10 isolates that have been shown to have closeness to several strains of bacteria, such as Raoultella terrigena, Serratia marcescens, Serratia nematodiphila, Enterobacter hormaechei, Enterobacter cancerogenous, Enterobacter cloacae, Enterobacter asburiae, Citrobacter murliniae, Pseudomonas fluorescens. depicted in phylogenetic analysis. Based on the phylogenetic analysis, the L5S2 10-7 isolate has similarities with the Enterobacter asburiae strain, while the L2S1 10-6 isolate is closely related to the Enterobacter cancergenous strain, Then the Citrobacter murliniae strains were closely related to L5S5 10-8 and L1S3 10-7 isolates. In addition, the Enterobacter hormaechei strain also has a close relationship with isolate L3S1 10-8, and the Raoultella terrigena strain has a close relationship with isolate L5S2 10-6. The L1S5 10-6 and L3S5 10-7 isolates had the same similarity based on genetic characters but had different abilities in helping the performance of plants belonging to the rhizobacteria group.