Community Analysis of Endophytic Bacteria from the Seeds of the Medicinal Plant Panax notoginseng

Shuai Liu,Limei Chen,Hongjuan Nian,Xiuming Cui,Dinghua Li

doi:10.5539/jas.v9n2p37

Abstract

Panax notoginseng is a traditional Chinese medicine. The roots of P. notoginseng can be used for treatment of diseases and raw materials in Chinese medicinal products. High yield and quality roots require cultivation in shade and humid conditions for 3 years. The long period cultivation makes P. notoginseng vulnerable to infect by pathogens. So control diseases are vital for the high yield and quality of P. notoginseng. The seed is the carrier systems of many probiotics and pathogens. To explore the indigenous bacterial community diversity, the endophytic bacteria from the seeds of the medicinal plant P. notoginseng were isolated and identified using traditional cultivation methods in combination with molecular technique. A total of 137 endophytic bacteria strains were isolated. The 16S rDNA of these strains was amplified and subjected to amplified ribosomal DNA restriction analysis (ARDRA) with restriction enzyme HaeIII. All the isolated strains were grouped into 9 OTUs (Operational Taxonomic Units) on the basis of the similarity of the ARDRA band profiles. Each representative strain of 9 OTUs was selected for sequencing. r-proteobacteria was the most dominant group among the isolates (98.5%), containing eight genera. Pseudomonas was the most dominant genus (58 of 135 isolates), whose isolates occurred in the seeds collected from all three places. The second dominant genus was Enterobacter (20.7%), followed by uncultured bacterium (14.8%) and Stenotrophomonas (10.4%). Among the six areas sampled, endophytic bacteria in the seeds collected from Panlong of Yanshan exhibited species diversity and contained the most isolates. These results suggest an abundant diversity of bacterial community within the seeds of P. notoginseng. These data provide insights into monitoring the seed health and disease outbreak during seeding.

Highlights

Endophytic bacteria ubiquitously inhabit a majority of plant species (Lodewyck et al, 2002)
Molecular approaches based on 16S rRNA gene analysis have been successfully used for bacterial community analysis
The amplified ribosomal DNA restriction analysis (ARDRA) technique has been widely applied in genetic diversity studies of rhizobacteria (Dellagnezze et al, 2016; Mehri et al, 2011; Nievas et al, 2012; Santoro et al, 2016; Sanyal et al, 2016)

Summary

Introduction

Endophytic bacteria ubiquitously inhabit a majority of plant species (Lodewyck et al, 2002). These organisms can be isolated from surface-disinfected plant tissues, including seeds, roots, stems and leaves and are not harmful to the hosts (Hallmann et al, 1998). Endophytic bacteria may promote plant growth and suppress plant diseases (Feng et al, 2006). The root-rot disease is the most destructive one (Sun et al, 2004), which was caused by soil-borne fungal pathogens

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