A Study On The Isolation And Identification Of Endophytic And Rhizosphere Bacteria In Four Aromaticspices Plants And The Screening Of Aromatic Bacteria

Out of all the widely cultivated crops, Calendula officinalis L., Rosmarinus officinalis L., Lavandula angustifolia Mill., and Pelargonium graveolens L’Her. are four important economic cropsin China nowadays. Basically, they are all used for extraction of volatile oil. The active ingredient in these volatile oil are reported to be antioxidant, antibacterial, anti-inflammatory, anti-cancer and anti-tumor, along with fragrance at the same time, therefore, they are applied in food, medicine and cosmetics and other fields. In this study, the endophytic bacteria and rhizospheric bacteria from the four kinds of plants spices were isolated. The pure cultured obtained strains were screened for volatile metabolites.While the pure cultured strains were to obtained, the screening of volatile metabolites avilable strains were performed. In addition, the volatile metabolites were appraised as well.Plants samples and rhizosphere soil samples were collected from Impressive Tobacco Farm in Shiling, Yunnan Province. Different isolation methods were used to treat these samples. As a result, a total number of 563 strains including 208 endophytic bacterial strains, distributed in 43 genera, were isolated,355 rhizospheric strains distributed in 48 genera, were isolated. Among them, a potent novel strain belongs to Hamadaea genus was isolated from rhizospheric soil, polyphasic taxonomy proof showed it is a new strain of Hamadaea genus, for which the name Hamadaea flava sp. was proposed.Based on previous isolates, it is possible to screen some strains with a pleasant fragrance. At first, the solid culture and liquid culture were prepared to abandon some strains which were smelly. Secondly, the GC experiment was used to test if there are possible volatile metabolites. Then MS was proposed to analyze these volatile metabolites. After the whole screening experiment, two strains YIM C0262 and YIM X0007 were successfully detected and initially identified their volatile metabolites. Even though both of these strains belong to the genus Streptomyces, there was a huge difference in the metabolites of the both. Strain YIM C0262 was detected with benzaldehyde and GMS (Geosmin); Strain YIM X0007 was elemene, elemol, (3-eudesmol, a-eudesmol and GMS (Geosmin) with higher response value, moreover, there are rarely literature reporting these metabolites can be produced by microbe, especially elemene, which has been in clinical use of anti-cancer drugs. Normally, it is extracted directly from plants, it has not been found in a microbial metabolism.A further determination was necessary for the strain YIM X0007. In order to perform a separation and identification experiment of its metabolites, a larger-scale fermentation was finished and the extraction of the metabolites was done. However, through a thin-layer chromatography pre-experiment, it was found the strain YIM X0007 produces a large number of diverse metabolites, which affected the isolation of single metabolite. Now, five compounds has been isolated from the strain, and the appraisal reminds.In conclusion, it indicates that there is a rich resource, which can be used to screen specific species and research microbial metabolism, in the plant endogenous environment and rhizosphere environment. Moreover, one individual strain was selected with valuable volatile metabolites, therefore, a further detection and identification of its metabolites will benefit for future applying.