Soybean Salt Stress Testing - December 2012
[University of Arkansas Division of Agriculture Research and Extension University of Arkansas System. Arkansas Soybean Promotion Board. Dr. Ken Korth, Professor of Plant Pathology, University of Arkansas]
I’m Dr. Ken Korth, Professor of Plant Pathology here at the University of Arkansas. I’ve been working with Dr. Pengyin Chen, our soybean breeder, on salt tolerance tests for the last three years now. We really focus on the molecular aspects of this project. And that is really looking at how the plant responds to salt stress. [Video shows soybean plants in pots.]
[Dr. Korth in a greenhouse with soybean plants.] So the typical experiment that we do is to basically stress the plant in some way and then we come back once the plant is showing some signs of damage and then we collect tissue and really analyze what’s going on inside the plant at the molecular level and especially at the level of gene expression. So what we have here are two types of soybean plant, two varieties of soybeans. Both of these have been treated with 100 millimolar sodium chloride, which is a pretty high salt concentration. So they’ve been treated on a daily basis for several weeks and you can see this plant is still looking pretty good. Nice green leaves, big healthy fully expanded leaves. The variety over here is what we call an includer. We know that this variety picks up chloride ions from the salt solution and accumulates those in the leaves. These plants tend to be much more sensitive to salt damage than this type, which we call an excluder. This type of plant does a better job of keeping out the chloride ions, keeping them in the soil, in the roots, and not transporting them up to the leaf tissue.
So after this step, what we do is collect the tissue, we isolate nucleic acids from these leaves and then we analyze differences in gene expression. So under different conditions, plants respond just like animals by turning on or turning off certain genes. The genes that get turned on we think are involved in helping that plant cope with that stress. And so what we do is to then look at which genes get turned on or which genes get turned off in either of these plants and our long term goal is to work with our breeder, Dr Chen, apply that understanding to developing improved varieties.
[www.uaex.edu. University of Arkansas Division of Agriculture Research and Extension University of Arkansas System. Arkansas Soybean Promotion Board]