Efficiency comparison of three methods for extracting genomic DNA of the pathogenic oomycete Pythium insidiosum.

Background : The fungus-like organism Pythium insidiosum is the causative agent of a life-threatening tropical infectious disease, pythiosis, which has high rates of morbidity and mortality. A lack of reliable diagnostic tools and effective treatments for pythiosis presents a major challenge to healthcare professionals. Unfortunately, surgical removal of infected organs remains the default treatment for pythiosis. P. insidiosum is an understudied organism. In-depth study of the pathogen at the molecular level could lead to better means of infection control. High quality genomic DNA (gDNA) is needed for molecular biology-based research and application development, such as: PCR-assisted diagnosis, population studies, phylogenetic analysis, and molecular genetics assays. Objective : To evaluate quality and quantity of the P. insidiosum gDNA extracted by three separate protocols intended for fungal gDNA preparation. Material and Method : Seven P. insidiosum isolates were subjected to gDNA extraction by using conventional-extraction, rapid-extraction, and salt-extraction protocols. Results : The conventional protocol offered the best gDNA in terms of quality and quantity, and could be scaled up. The rapid-extraction protocol had a short turnaround time, but the quality and quantity of the gDNA obtained were limited. The salt-extraction protocol was simple, rapid, and efficient, making it appealing for high throughput preparation of small-scale gDNA samples. Conclusion : Compared to rapid-extraction protocol, both conventional-extraction and salt-extraction protocols provided a better quality and quantity of gDNA, suitable for molecular studies of P. insidiosum. In contrast to the other two methods, the salt-extraction protocol does not require the use of hazardous and expensive materials such as phenol, chloroform, or liquid nitrogen. Keywords : DNA extraction, Genomic DNA, Oomycete, Pythiosis, Pythium insidiosum