Detection of Phytophthora erythroseptica in Soil Using Nightshade as Bait Combined with PCR Techniques
Nanayakkara. U. N Singh. M Al-Mughrabi. K. I Peters. R. D
American Journal of Potato Research ; 2010 [Vol.87] Pages:67-77
Abstract
Pink rot caused by Phytophthora erythroseptica is found in most major potato-growing regions of the world. The pathogen can survive for many years in soil by means of oospores which are disseminated from diseased potato tissues. The ability to detect the pathogen in soil could be a valuable management tool that enables growers to plan control strategies depending on the presence of pathogen propagules in a particular field. However, soils are one of the most challenging environmental matrices to obtain microbial DNA that will support PCR. A method was developed that combined traditional baiting technique with PCR methods to detect P. erythroseptica in infested soil samples. Hairy nightshade (Solanum sarrachoides Sendt.) and bitter nightshade (Solanum dulcamara L.) two leaf stage (TLS) seedlings and cotyledon leaves successfully baited P. erythroseptica from zoospore suspensions, artificially inoculated soils and naturally infested soils. The pathogen was detected in the bait tissue with PCR methods. PCR increased the precision of the bait test. However, time was still required for the pathogen to infect and develop on the bait tissues. Although P. erythroseptica was detected from some bait plants only after 2 days of incubation, 10 days of incubation produced consistent results across the replicates with hairy and bitter nightshade cotyledon leaves and TLS seedlings.
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