Using molecular biology to look for disease resistance in soybean
Cercospora leaf blight is the No. 1 fungal disease in Louisiana’s No. 1 row crop – soybeans.
The emerging disease, which has appeared only in the past five to 10 years, has no resistance in any soybean lines, according to LSU AgCenter plant pathologist Zhi-Yuan Chen.
The Cercospora fungus survives in infected seeds and plant residue, and spores form on the residue surface during warm, humid weather, experts say. The spores are wind-blown or rain-splashed to new soybean tissue where infection occurs. Seeds also can carry the fungus.
The foliar disease can remain latent in growing soybean plants for several weeks before they show symptoms. In severe cases the disease can cause defoliation, and it is associated with the green stem disorder.
In an attempt to solve the lack of resistant plants, Chen has been using molecular tools to find ways to make soybeans resistant to the disease.
“There are no known resistant lines that we can use to learn how soybeans defend themselves against Cercospora kikiuchii infection using the available molecular tools,” Chen said.
Instead, Chen’s research team in the Department of Plant Pathology and Crop Physiology has been focusing on identifying genes that produce cercosporin, a toxin that can suppress a plant’s defense mechanism.
So far, he has identified two genes using proteomics – the branch of molecular biology that studies the full set of proteins encoded by a genome – and gene disruption studies. These genes appear to be important for cercosporin production by the pathogen.
The genes are currently being tested for their ability to suppress the toxin and the resulting fungal infections. If they actually do what the researchers believe, these genes will be introduced into new soybean lines to produce resistant varieties.
Chen’s laboratory team also has identified several genes that potentially can play an important role in soybean resistance to rust infection. They currently are testing these genes using a virus-induced gene silencing approach.
“Preliminary data show that soybeans with reduced expression of these genes are more susceptible to rust infection, indicating that enhancing the expression of these genes in the future could provide better protection against soybean rust diseases,” Chen said.
- US soy exports to China could drop with crush-margins at 2-yr low
- Corn to see record production for 2014-15
- Maximizing buyer power in volatile markets
- Insight into drought tolerance of TAM wheat varieties
- Ag markets turned mostly lower Tuesday morning
- GMO safety, weed control top concerns as U.S. study kicks off
- U.S. GMO labeling foes triple spending in first half of this year
- Activists fighting Golden Rice even more in 2014
- Source shows half of GMO research is independent
- White House issues veto threat on bill to block WOTUS rule
- Stoller soybean research produces 214 bushels per acre
- FCC aims to offer high-speed internet to rural America