Identification of Rhizobacterial Strains by Genotyping
Date
2018-01-21
Authors
غانم, منار أحمد أسعد
Journal Title
Journal ISSN
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Publisher
جامعة النجاح الوطنية
Abstract
Identification and classification of plant growth promoting rhizobacteria (PGPR) is needed because theses bacteria have very important and significant role in agriculture. PGPRs are considered as the best substitution for chemical fertilizers. By their different mechanisms, PGPR can increase the plant growth rate and crop yield. There were different methods used in bacterial characterization, mainly based on histochemical properties. Molecular tools were also used recently including phenotyping and genotyping methods. One of the most useful genotyping techniques is polymerase chain reaction (PCR). Based on 16S ribosomal RNA gene analysis bacterial strains could be identified and classified. About 21 samples were collected from different sites in Nablus district. After serial dilution 7 different colonies were subjected for histochemical characterization. Four different defined strains of Brevibacillus formosus, Brevibacillus agri, Staphylococcus aureus and Escherichia coli, in addition to two unknown isolates (numbered as Clone 3 and Clone 5) were chosen for molecular identification and genotyping.
DNA extraction was done by simple boiling method; which was tested for its efficacy and simplicity. Two pairs of primers (27F and 1492R) were chosen after several trials to be able to amplify the 16S ribosomal RNA genes of most rhizobacteria. The results were showed that the sequenced portion of the rRNA gene were able to identify the bacterial genus and putatively species using the available Bioinformatics tools such as BLAST and phylogenetic tree. By this method we were able to identify the two clones that were isolated from rhizospheric zones of plant reeds in Nablus district. These clones were identified as Planomicrobium sp. and Pseudomonas sp. for Clone 3 and Clone 5 respectively. These two isolates are indeed has PGPR’s activities. This would be considered as the first Palestinian isolates to be nominated and has PGPRs activity. The study recommend to continue screening the other isolates and do further molecular identification of these isolates. It was also worth to recommend testing these isolates and to measure their capability in promoting plant growth as well as their antagonist activity against soil borne pathogens.
Description
Keywords
plant growth promoting rhizobacteria , phenotyping , genotyping , 16S rRNA gene , PCR