These genes could save soybeans from sudden death

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Researchers have found a gene in the plant Arabidopsis that could protect soybeans from diseases, like sudden death syndrome, that plague the plant.

“We think we may find that multiple genes working together will build the resistance levels…”

Madan Bhattacharyya, a professor of agronomy at Iowa State University and lead author of the study, says his current research points toward several Arabidopsis genes that could act in concert to help soybeans fight off sudden death syndrome, a disease that has caused millions of dollars in crop losses for Iowa farmers.

“We’ve started to map many of these genes, and we think there are many different mechanisms that work together to create resistance of Arabidopsis against two soybean pathogens,” Bhattacharyya says. “We’re testing a hypothesis that putting a combination of these Arabidopsis genes into soybeans confers a high level of disease resistance.”

Bhattacharyya says all complex organisms, whether plants or animals, demonstrate resistance to most of the potential pathogens they encounter in their environment. Arabidopsis, a small flowering plant that serves as a good model plant in experimental settings, shows resistance to two soybean pathogens that cause sudden death syndrome and root rot, respectively.

So Bhattacharyya and his colleagues have spent years combing the genome of Arabidopsis to identify genes that might contribute to that resistance. He then uses transgenic techniques to insert likely genes into soybean plants at Iowa State’s Plant Transformation Facility.

The study identifies one of those genes, called PSS1, as a means of improving soybean resistance. The transgenic soybean plants carrying this gene showed enhanced SDS resistance in two consecutive years under field conditions, Bhattacharyya says. The SDS resistance encoded by this gene will complement the natural SDS resistance, which is encoded by 40 or so genes each conditioning small amounts of resistance.

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He expects incorporation of additional PSS genes together with natural SDS-resistance genes will provide soybeans robust and durable resistance. Finding the optimal combination of those genes is the current research goal of his lab, he says.

“We’re hoping in the next few years to test how combinations of PSS genes affect SDS resistance,” Bhattacharyya says. “We think we may find that multiple genes working together will build the resistance levels.”

The Iowa Soybean Association and Consortium of Plant Biotechnology Research funded much of the early research dating as far back as 2004, Bhattacharyya says. Currently, a grant through the Agriculture and Food Research Initiative from the US Department of Agriculture’s National Institutes of Food and Agriculture, as well as the United Soybean Board and the Iowa State agronomy department, provide funding.

The researchers report their findings in the journal Plant Physiology.

Source: Iowa State University