Vulnerability of DNA hybridization in soils is due to Mg2+ ion induced DNA aggregation

Xiaofang Wang, Hyojin Kweon, Seokho Lee, Hyejin Shin, Beelee Chua, Mark R. Liles, Ming kuo Lee, Ahjeong Son

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


The NanoGene assay is an inhibitor-resistant gene quantification assay based on magnetic bead and quantum dot nanoparticles. It employs a set of probe and signaling probe DNAs to capture target DNA via hybridization. Using simple DNA preparation that bypasses conventional DNA extraction, it was able to detect and quantify specific bacterial genes in environmental sample. In this study, the vulnerability of the NanoGene assay to the presence of various environmental factors was investigated. A total of 43 soil samples were inoculated with 109 CFU/mL of Pseudomonas putida prior to DNA isolation without purification. Subsequently, the NanoGene assay was performed for quantitative detection of P. putida with respect to 12 soil properties including pH, moisture, humic acids, organic matter, sand, silt, clay, cation exchange capability, sodium, potassium, magnesium, and calcium. Using multiple linear regression, the NanoGene assay was found to be particularly vulnerable to the presence of Mg2+, which was selected as a major variable (P = 0.001). The vulnerability of the NanoGene assay to Mg2+ was further explored by atomic force microscopy, which indicated significant Mg2+-mediated DNA aggregation. The inhibition of the NanoGene assay from some soil samples as a consequence of DNA aggregation could therefore be prevented by the use of Mg2+ chelators such as EDTA, enabling application of this method across diverse soil types.

Original languageEnglish
Pages (from-to)300-308
Number of pages9
JournalSoil Biology and Biochemistry
Publication statusPublished - 2018 Oct


  • Atomic force microscopy
  • DNA hybridization
  • Gene quantification
  • Magnesium (Mg) ion
  • NanoGene assay

ASJC Scopus subject areas

  • Microbiology
  • Soil Science


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