Seed Today - Q1 2008 - (Page 56)

Soybean SDS Lab Test Inexpensive assay is reliable screening tool for sudden death syndrome resistance A simple, cheap lab test developed at Southern Illinois University (SIU), Carbondale, can unerringly detect Sudden Death Syndrome (SDS), a fungal disease in soybean seedlings caused by Fusarium solani. somewhere by the end of the growing season. If the disease was present, breeders could make breeding crosses with the survivors and repeat the process during the next season. But sometimes the disease didn’t appear, and sometimes when it did, it didn’t behave normally and would disappear midseason. Lightfoot says people had done two things wrong in their attempts to develop an assay. They had grown the Fusarium solani fungus on rich media, so it wasn’t hungry (which could lead to false negatives). The other mistake was to just jab the plant with the fungus or put the fungus in humongous quantities in the ground, making the disease inevitable (leading to false positives). Lightfoot’s patented method begins by growing the SDS fungus in a mix of corn meal, sand, mineral salts and agar. “That’s enough to keep it alive, but not fat, lazy or happy,” he says. The fungal mixture is then mixed into soil. Vulnerable seedlings planted in that infected soil will contract the disease; seedlings with resistance potential won’t. Soybean SDS fungal disease (SIU photo) Rapid DNA/RNA Tests Isothermal amplification of nucleic acids provides results in five minutes EnviroLogix Inc., Portland, ME, and Ionian Technologies Inc., San Diego, CA, have agreed to collaborate on the development, manufacturing, marketing and sale of rapid tests for detecting genes or gene sequences of interest to agricultural biotechnology markets. Under terms of their exclusive collaborative development agreement, which includes future tests serving the environmental, horticultural and food safety markets, EnviroLogix will identify appropriate seed biotech partners and gene targets, then market and sell products developed and manufactured by Ionian. The tests are targeted for “in field” or “in house” detection of the gene sequences of interest. thermal amplification of nucleic acids, either DNA or RNA, in approximately five minutes, with PCR-quality sensitivity. Even the fastest PCR reactions require about 30 minutes, hence the technology will provide a significant speed advantage compared to PCR. The amplification products can be detected using a variety of proprietary and standard methods, including fluorescent and lateral-flow readouts. Current tests for identifying engineered seeds, grains or crops rely on detecting transgenic proteins with onsite immunostrips “lateral flow” tests or lab-based ELISA methods, or PCR. All biotech products have or will have different gene sequences compared to non-engineered products, and thus the need for rapid—and sensitive—nucleic acid testing. Ionian’s isothermal amplification methods are sensitive enough to detect single base changes between two otherwise similar sequences. Once commercialized, the test will help breeders more quickly select for SDS-resistant soybean varieties. “You can do a reliable assay in the greenhouse in a plastic cup and four weeks later, you’ll see the result,” says David A. Lightfoot, a biotechnologist in SIU’s College of Agricultural Sciences, who developed the procedure. “The seedlings develop the leaf symptoms and the roots rot or they don’t. It works every time, and the labor cost is about one dollar per assay,” Lightfoot says. Lightfoot received patent 7,288,386 for the assay on October 30. The patent will allow SIU to negotiate with private companies to license the assay. “Now that the important things about the assay are protected, we can use it without fear of infringement by others,” Lightfoot says. Dependable Fungal Infection Lightfoot explains that breeding SDSresistant soybean varieties was pretty much hit or miss. Breeders would plant a bunch of beans in a flock of fields and hope the disease would show up Rapid process Following a rapid sample extraction step, the technology provides for iso- 56 First Quarter 2008

Table of Contents Feed for the Digital Edition of Seed Today - Q1 2008

Seed Today - Q1 2008 Contents Editor’s Notes Cover Feature: Agrecol® Corporation Reed Barker, Ph.D. Cal/West Seeds Inc. Annual GM Use Report Bt Resistance Reported Camelina Tony Harper Gayle Jacklin According to ASTA Krauter Structures AOSCA AOSA/SCST GM and Greenhouse Gas Seed Associations Ad Index

Seed Today - Q1 2008

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.