Molecular identification of potential rhizobacteria isolated from maize (Zea mays L.)

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.