Research Plant Physiologist

Plant Science Research Unit

Red River Valley Agricultural Research Center

United States Department of Agriculture Agricultural Research Service (Washington, DC)

I study molecular aspects of bud dormancy in perenial weeds such as leafy spurge and canada thistle, crop-weed interactions, and genomics of invasiveness in leafy spurge.

We use genomic-based technologies (primarily microarrays) to identify and characterize pathways regulating bud dormancy in leafy spurge (Euphorbia esula) and Canada thistle (Cirsium arvense). Our team in the plant Science Research unit has developed an extensive EST database (19,000+ unigenes)for leafy spurge which we have combined with ESTs from cassava (another Euphorb) to produce microarrays with 23,000 unigenes. We have used these microarrays to study transcriptome changes that occur during shifts between dormant and growing states in leafy spurge crown buds (underground adventitious shoots). We have also used these to look at drought stress and pathogen attack, and study differences between leafy spurge in it's native and invaded ranges. We have also used corn microarrays to study the impact of weeds on corn growth and development in collaboration with Drs. Sharon and David Clay at South Dakota State University. Our current focus is on a group of MADS-box transcription factors that we identified in our microarray analysis that appear to regulate dormancy induction.

1982-present I am a Knight, Laurel, and Duke in the Society of Creative Anachronism

2008 31. Horvath DP and Clay S (2007) Heterologous hybridization of cotton (Gossypium hirsutum) microarrays with velvetleaf (Abutilon theophrasti) reveals physiological responses due to corn competition. Weed Sci. 55: 546–557: Paper of the Year - Weed Science