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.
- Deere to lay off more than 600 at four U.S. plants
- The four pillars of seeing opportunities in problems
- New DuPont Afforia herbicide introduced for soybeans
- Cooperative exits retail and automotive business
- Slow pace of rail recovery stirs fear of future woes
- RTK brings higher level of accuracy to farmers
- No El Niño in 2014? Drought-weary California in trouble
- Suspected Bt corn rootworm resistance in Pennsylvania
- BioNitrogen to build second fertilizer plant in Texas
- Commentary: Setting the record straight on 'Waters of the U.S.'
- Soybean aphid numbers on the rise
- Solar energy jobs increase, wind power decrease