Poster Presentation Australian Society for Microbiology Annual Scientific Meeting 2018

Root microbial Dynamics influenced by Quorum-Sensing Signal Molecules on Continuous Cropping Soils of Ginseng (#344)

Chang Eon Park 1 , YeonGyun Jung 1 , Huy Pham Quang 1 , Jae-Ho Shin 1
  1. School of Applied Biosciences, Kyungpook National University, Daegu, Republic of Korea

Ginseng (Panax ginseng C.A Meyer) is traditionally well known as a widely used medicinal product. Since the 1900s, the demand for ginseng has soared, and the plant has been cultivated in earnest. Currently, about 80,000 tons of ginseng are produced worldwide. However, ginseng requires long-term cultivation period of 5 ~ 7 years, and it is necessary to search for a way to reduce extreme damage. Although the series damage is known to be caused by fungi, there have been reports to indirectly deduce the microorganism by isolating the fungi, but the study on the microbial composition of the whole is insufficient.

Quorum-sensing (QS) signaling materials are well known for regulating bacterial cell density. Among them, N-acyl homoserine lactones (AHL) is known to control the cell density of Gram-negative bacteria.

In this study, continuous ginseng cultivated sites were located in the Yeongju-si, Republic of Korea. The soil samples were collected with 5 years over continuous cropping history. In addition, we observed that the QS signaling (QSS) molecules regulate bacterial cell density, and we tried to cultivate ginseng in the diseased soil and treat the QSS molecules to change the microorganism. The disease did not occur in the place where the QSS molecules were treated, and the disease occurred in the treatment field in which the soil was sterilized and only treated with water.

Microbiome was analyzed using the next generation sequencing instrument. The V4-V5 region and ITS2 region were used for bacteria and fungi community analysis. The SILVA database and the UNITE database were used for microbiome analysis. In the case of fungi, the results were not well studied globally so that the results obtained using NCBI blastn were more than 97% homologous to establish its own database. As a result, Acidobacteria and Gemmatimonadetes were relatively frequent in bacterial community. In addition, the fungal community showed no tendency in the dominance of Fusarium spp.. Botrytis fungi were also detected according to the results of the newly constructed database, and it was observed that Botrytis fungi were present in the diseased areas.

Biodiversity was analyzed with Shannon-Wiever index, Margalef’s richness, and Pielou’s evenness. The changes in fungal community were analyzed by the diversity index because there was no particular tendency. The total diversity results showed the bacterial total diversity was decreased in the healthy soils and fungal total diversity was increased in the healthy soils.

  1. Li, Y., Ying, Y. and Ding, W. 2014. Dynamics of Panax ginseng rhizospheric soil microbial community and their metabolic function. Evidence-Based Complementary and Alternative Medicine 2014.
  2. Miller, M. B. and Bassler, B. L. 2001. Quorum sensing in bacteria. Annual Reviews in Microbiology 55(1): 165-199.
  3. Pielou, E. 1975. Ecology diversity. J. Wiley and Sons, New York.