ARS Scientists Develop New Strategy to Investigate PSD in Soybeans

Scientists from the USDA Agricultural Research Service (ARS) developed a new technique that could boost the search for soybeans with resistance to fungus that causes Phomopsis seed decay (PSD). The pathogen degrades soybean seed and decreased the quality of its protein and oil. Outbreaks of PSD in 2012 in 16 U.S. states led to losses of over 2 million bushels.

The researchers used the common soil bacterium Agrobacterium tumefaciens to transfer genes for an antibiotic marker and green fluorescent protein (GFP) into the nucleus of the fungus' cells. This led to new strains of the fungus that produce the protein and exhibit a green glow when exposed to light in the blue-to-ultraviolet range.

Soybean seedlings were inoculated with the modified strains to study how the infection occurs in the tissues of both resistant and susceptible soybean germplasm lines. The approach should also help in identifying sources of PSD resistance that are undetected when using conventional disease screening methods, such as those requiring field observation of symptoms.

The study was published in the Journal of Microbiological Methods.

Read more at http://www.ars.usda.gov/is/pr/2014/140609.htm.