Bacterial endophytes inhabiting medicinal plants are less explored, but are diverse and play crucial roles in regulating growth and development of the host. Metagenomics using Illumina MiSeq platform facilitate whole community level characterization. The present study reports the diversity of bacterial endophytic microflora from the medicinal plant Emilia sonchifolia (Linn.) DC. Metagenomic analysis of medicinal plants leads to the identification of novel organisms or genes which will help the correlative elucidation of plant-microbe interactions. Effective sequences were amplified from 16S rRNA gene V3-V4 variable region. OTU analysis at different taxonomic level clearly catalogues two Phyla viz. Proteobacteria and Firmicutes which belonged to Gammaproteobacteria and Bacilli. In these classes five orders such as Enterobacteriales, Pseudomonadales, Xanthomonadales, Bacillales and Betaproteobacteriales were detected. Among these orders five families were identified in which the most predominant was Enterobacteriaceae and Pseudomonadeaceae while the other three families viz. Xanthomanadaceae, Planococcaceae and Burkholderiaceae were less represented. At genus level very less number of bacteria were identified while a bulk majority remained unclassified. Of the seven identified genus the most prominent one was Pseudomonas followed by Stenotrophomonas, Cronobacter, Lysinibacillus, Pantoea, Kluyvera and Pseudorhodoferax. At species level only two were identified vz. Pseudomonas otitidis and P.geniculate. Alpha diversity analysis using various statistical indices like Simpson and Shannon explains the diversity of microbiome. Next generation sequencing survey of DNA sample extracted from host plant through metagenomic data screening identified different endophytic bacteria which are difficult to grow in culture conditions.
Studies on the genome of endophytes reveal the metabolic potential of endophytic microbiome including both culturable and unculturable fractions. The metagenome analysis through the Illumina HiSeq platform gives access to the genetic data encrypted for the molecular machinery, which takes part in plant growth promotion activity of the endophyte in various aspects including production of plant growth hormones and enhancing nutrient availability for the host plant. The present work was undertaken to identify the genes involved in plant growth promotion activities from the endophytes of Emilia sonchifolia(Linn.) DC. through metagenome analysis. Metagenomic studies include the analysis of functional annotations which aid in the detection of biocatalysts taking part in the metabolic pathway of host plants. The annotations of expressed genes in different databases like NCBI Nr, KEGG, eggnog and CAZy resulted in enlisting the vast array of information on the genetic diversity of the endophytic microbiome. The metagenome analysis of endophytic bacteria from the medicinal plant E.sonchifolia unveiled characteristic functional genes involved in plant growth promotion such as nitrogen metabolism (nif) and siderophore production (enterobactin category), ipdC and tnaA (IAA producing), ACC deaminase coding genes (regulation of elevated ethylene levels in host tissues), Mo-Nitrogenase, nitrous-oxide reductase (nosZ), nitrate reductase (narG, napA), nitrite reductase (nirD) (nutrient assimilation and absorption) enterobactin siderophore synthetase components F and D and acid phosphatase genes. This clearly explains the effective plant-microbe relationship and the role of bacterial endophytic microbes in regulating the growth of host plants.
The harmless immigration of endophytic microflora in plants and their ability to synthesize various valuable compounds has attracted many researchers to work with plant-microbe interactions and also to exploit them for agricultural and medical applications. This investigation has been carried out to study endophytic bacteria in Biophytum sensitivum (L.) DC by the isolation, characterization and identification based on morphological features, cell characteristics, biochemical tests, plant growth promotion, 16S rDNA sequencing and phylogenetic analysis. Five different bacterial isolates were identified from this study using BLAST analysis of the 16S rDNA sequences and were submitted in GenBank followed by retrieval of accession numbers. The identified bacteria with their accession numbers are Staphylococcus sp. strain (MH050396); Bacillus sp. strain (MH050388); Bacillus cereus strain (MH050384); Bacillus subtilis strain (MH050389) and Bacillus sp. strain (MH050399). All isolates except Bacillus sp. strain (MH050399) produced Indole -3-acetic acid and the highest amount of 14.50µg/ml was obtained from Bacillus subtilis strain (MH050389). All bacterial endophytes reported in this study produced ammonia and siderophore thus indicating their role in plant growth promotion.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.