Determing Efficacy of qPCR to Determine Bradyrhizobium japonicum Populations in Fields

Crop Soybean
Start Date2016
End Date2017
Principal InvestigatorOresnik, Ivan, University of Manitoba
MPSG Financial Support$26,443
Total Project Funding$52,885

Research Objectives

Determine if a method to quantify B. japonicum using qPCR can be extended to field conditions to be used as a predictive tool to determine if soybean crop needs to be inoculated

Project Description

Farmers in Manitoba generally inoculate their soybeans every year using Bradyrhizobium japonicum. However, after repeated successful inoculated soybean crops, populations of B. japonium can build up and overwinter, providing sufficient inoculum for proceeding soybean crops. Farmers may not need to inoculate soybeans after a history of soybeans have been established in a particular field, however, there are no tools that farmers can use to estimate residual soil inoculum.  Providing a rapid and accurate assay for farmers to be able to determine if inoculation of soybean with B. japonicum is could decrease costs by eliminating the need for applying supplemental inoculant.

The successful use of B. japonicum as an inoculant on soybean is dependent upon the number of effective bacteria that are present as well as the ability of the bacteria to colonize the soil and to interact with the host plant.  From previous studies, a quantitative PCR test was developed: the test involves extracting all the DNA from a small sample of soil and using specific primers that are designed to detect B. japonicum. If any B. japonicum DNA is present, it will be amplified, and the rate at which it is amplified can be used to determine the number of B. japonicum that are present in a sample. The entire assay, from extraction to enumeration, can be carried out within a day.o determine if a method to quantify B. japonicum using qPCR can be extended to field conditions to be used as a predictive tool to determine if soybean needs to be inoculated.