Ken Korth - Professor of Plant Pathology, AR P3 Center Co-Campus Lead - University of Arkansas, Fayetteville

korth
Phone: 479-575-5191 (Office)
Address: Department of Plant Pathology | PTSC 217 | University of Arkansas | Fayetteville, AR 72701
Email: kkorth@uark.edu

Affiliations:

 Cluster Identification:
- Plant Metabolomics Cluster
- Plant Interactions with Other Organisms (Cluster lead)

Research Areas/Expertise:
- Plant-insect interactions
- Terpene metabolism
- Biotic and abiotic stress responses

Research Summary | Selected Publications | Lab Members | Key Collaborators | Research Projects | Links

Research Summary:

The Korth lab uses tools of molecular biology and biochemistry to examine how plants respond to and cope with both biotic and abiotic stress. Mechanisms of salt tolerance in soybean, insect responses in Medicago truncatula, and high temperature impacts on grain formation in rice are the focal areas of the lab. Metabolite profiles of legumes serve as key indicators of how plants are responding to stressful conditions.  In addition to metabolomic approaches, transcriptome profiles have identified a large number of candidate genes that play roles in responses to stress.  These analytical approaches are coupled with the strong genetic resources available in these different plant species, with the ultimate aim of tackling problems of importance to agricultural producers in Arkansas and beyond.

Selected Publications:

 

  • Venu, R.C., Madhav, M.S., Sreerekha, M.V., Nobuta, K., Zhang, Y., Peter Carswell, P., Boehm, M.J., Meyers, B.C., Korth, K.L. & Wang, G.L. (2010) Deep and comparative transcriptome analysis of rice plants infested by beet armyworm (Spodoptera exigua) and water weevil (Lissorhoptrus oryzophilus) insects. Rice 3:22-35.
  • Navia-Giné, W.G., Yuan, J.S., Mauromoustakos, A., Murphy, J.B., Chen, F. & Korth, K.L. (2009) Medicago truncatula (E)-β-ocimene synthase is induced by insect herbivory with corresponding increases in emission of volatile ocimene. J. Plant Physiol. Biochem. 47:216-425.
  • Park, S.-H., Doege, S.J., Nakata, P.A. & Korth, K.L. (2009) Medicago truncatula-derived calcium oxalate crystals have a negative impact on chewing insect performance via their physical properties. Entomol. Exper. et Applicat. 131:208-215.
  • Charlson, D.V., Korth, K.L., & Purcell, L.C. (2009) Allantoate amidohydrolase transcript expression is independent of drought tolerance in soybean. J. Exptl. Bot. 60:847-851.
  • Korth, K.L., Nakata, P.A., McGehee, Jr., R.E., & Nagarajan, R. (2010) Physical characteristics of calcium oxalate crystals as determinants in structural defense against chewing insects in Medicago truncatula.   In: Proceedings of the XIV International Congress of Molecular Plant-Microbe Interactions.
  • Navia-Giné, W.G., Gomez, S.K., Yuan, J., Chen, F., & Korth, K.L. (2009) Insect-induced gene expression at the core of volatile terpene release in Medicago truncatula.  Plant Signaling and Behavior. 4: 636-638.

Lab Members:


Lacy D. Nelson
Lab manager; Program Technician I 
ldnelson@uark.edu; 479-575-4520


Audra Harris
MS student (Plant Pathology Program)
amh011@uark.edu; 479-575-7081


Brynn Lawrence
MS student (Cell and Molecular Biology Program)
bka003@uark.edu; 479-575-7081


Jade Newsome
MS student (Plant Pathology Program)
janewsom@uark.edu ; 479-575-7081

Key Collaborators

 

- Dr. Terry Siebenmorgen, grain milling, food science
- Dept. of Food Science, University of Arkansas
- Dr. Lloyd Sumner, plant metabolomics 
- Plant Biology Division, Samuel Roberts Noble Foundation
- Dr. Paul Counce, rice physiology
- University of Arkansas Division of Agriculture, Stuttgart ,AR
- Dr. Steve Grace, plant physiology
- University of Arkansas-Little Rock
- Dr. Pengyin Chen, soybean breeding
- Dept. of Crop, Soil and Environmental Science, University of Arkansas

Research Projects

Role of plant metabolites in pest defense.  

Plants lack an advanced immune system and most live a sedentary life, so they must utilize many mechanisms to fend off pathogens and insects.   In addition to structural defenses, plants use a multitude of chemical strategies for defense.  We focus studies on a set of secondary metabolites called terpenoids.  In response to herbivore damage, plants produce many volatile and non-volatile terpenoids that can serve as signals to other insects, repellants, and anti-feedants. Terpenoids are a large and varied class of plant secondary metabolites that play important roles in plant interactions with pests.  Among this class of compounds are the triterpene saponins that are thought to have insecticidal activities.  Metabolite analysis of lines of the barrel medic, M. truncatula, has been used to identify lines with either high or low levels of saponins.  These plant lines are now being used to tease apart the molecular regulation of saponin biosynthesis, and to examine the role that these compounds play in host defense against fungi, nematodes, and insects.  We have shown that following insect damage, levels of saponins increase dramatically, along with expression of genes playing a role in saponin biosynthesis.  Screening of M. truncatula accessions is being conducted to determine interactions with pests, and these data will be combined with studies of metabolite and transcriptome profiles.

 

 

Understanding salt tolerance in soybeans and other legumes.  
Salt affected soils continue to increase in the Mississippi Delta due to the increased use of irrigation and the decrease in aquifer water quality in the region. Salt affects soybean emergence and seedling survival, and decreases yield potential later in the season. Soybean varieties have varying levels of resistance to salt damage, depending on their genetic makeup as chloride “includers” or“excluders”.  We have optimized an easy and rapid screening process to screen for salt tolerant varieties in the greenhouse.  We are combining these screens with transcriptome and foliar mineral analyses to assess how different lines of soybean cope with high levels of salt.  We collaborate with a soybean breeder to utilize segregating populations of soybean to identify important genomic regions of use in development of improved varieties for farmers. 

 

Impacts of high nighttime temperatures on rice grain formation.  High nighttime air temperatures are especially harmful to rice during critical stages of grain filling, and result in lower yields and excessive chalkiness of grain endosperm.  This issue is of immediate concern because of recent field and mill observations in Arkansas and worldwide that demonstrate decreased rice quality and yield in response to high nighttime temperatures.  The effect has clear implications regarding effects of changing climates on agriculture and food production.  Chalk formation in rice results from loose packing of starch granules, and chalky grains are lower quality for millers and result in price reductions for rice growers.  We are measuring transcriptomes of heat-sensitive and -tolerant rice varieties, and trying to associate this information with chalk formation.  It is clear that genes encoding enzymes of sucrose and starch synthesis are down-regulated by high nighttime air temperatures, whereas genes for starch degradation are up-regulated.  Long term goals of this study are to translate gene sequence and expression information to development of molecular markers that will be of use to rice breeders. 

Impacts of high nighttime temperatures on rice grain formation.  

High nighttime air temperatures are especially harmful to rice during critical stages of grain filling, and result in lower yields and excessive chalkiness of grain endosperm.  This issue is of immediate concern because of recent field and mill observations in Arkansas and worldwide that demonstrate decreased rice quality and yield in response to high nighttime temperatures.  The effect has clear implications regarding effects of changing climates on agriculture and food production.  Chalk formation in rice results from loose packing of starch granules, and chalky grains are lower quality for millers and result in price reductions for rice growers.  We are measuring transcriptomes of heat-sensitive and -tolerant rice varieties, and trying to associate this information with chalk formation.  It is clear that genes encoding enzymes of sucrose and starch synthesis are down-regulated by high nighttime air temperatures, whereas genes for starch degradation are up-regulated. Long term goals of this study are to translate gene sequence and expression information to development of molecular markers that will be of use to rice breeders.

Links