North Carolina State Univ.
In a paper published online in Nature Genetics, North Carolina
State Univ. and U.S. Department of Agriculture crop scientists and plant
pathologists sift through millions of genetic sequence variations in the set of
all genes in maize (corn) to identify 51 gene regions associated with
resistance to Southern corn leaf blight disease—an important plant pathogen.
Finding out more about the mechanisms behind complex traits like disease
resistance has the potential to help plant breeders build the best traits into
tomorrow’s corn plants, including resistance to some diseases, says Dr. Jim
Holland, NC State professor of crop science, research geneticist for the U.S.
Department of Agriculture-Agriculture Research Service (USDA-ARS) and the corresponding
author of the paper.
Holland and study co-authors Dr. Peter Balint-Kurti, a USDA-ARS research
plant pathologist and geneticist who works in NC State’s plant pathology
department, and Kristen Kump, an NC State graduate student, joined researchers
from Cornell Univ., the Univ. of Delaware, and the Univ. of Missouri to examine
a set of 5,000 maize varieties called the maize nested association mapping
population. Using this population allowed the researchers to zero in on the
parts of the genome responsible for conferring resistance.
The researchers likened the search for Southern corn leaf blight resistance
gene regions in maize to looking for specific houses in a large city—without
knowing the addresses.
“Using this nested association mapping population, when we find associations
with Southern corn leaf blight disease, we know we’re on the right street and
maybe have the right house,” Holland
says. “If we know which genes control disease resistance, we can make better
predictions about which maize varieties will be resistant to disease and focus
on breeding those lines.”
Balint-Kurti hope to build upon these results to learn more about how genes
confer disease resistance to Southern corn leaf blight and whether they may
also provide resistance to other similar types of diseases in corn and other
Southern corn leaf blight is a moderate problem in the southeastern United States, Balint-Kurti says, and can be a
significant problem in Southeast Asia, southern Europe and parts of Africa. Prevalent in hot, humid climates across the
globe, it causes small brown spots on leaves. The spots get larger and
eventually spread to the whole plant. Severe infections can cause major corn
Balint-Kurti says the study provides “an unparalleled description of the
genetic architecture of disease resistance.
“Southern corn leaf blight is a model system for pathologists to study. This
research provides the most detailed description of the genetic basis of plant
disease resistance of which we are aware,” he added.
In a companion paper in Nature Genetics, Holland and his Cornell colleagues found
candidate maize genes related to leaf angle, an important trait that has
allowed growers to plant corn crops closer together, resulting in drastically
increased corn yields. That study also utilized the maize nested association
The research was funded by the National Science Foundation and the USDA-ARS.