Microarray analysis was used to identify changes in gene expression in corn leaves collected from plants at the V11–14 growth stage that resulted from competition with velvetleaf. The plants were grown in field plots under adequate N (addition of 220 kg N ha−1) and irrigation to minimize N and water stress. Consequently, only differences resulting from competition for micronutrients, light, and perhaps allelopathic stress were anticipated. Genes involved in carbon and nitrogen utilization, photosynthesis, growth and development, oxidative stress, signal transduction, responses to auxin and ethylene, and zinc transport were repressed in corn growing in competition with velvetleaf. Very few genes were induced because of competition with velvetleaf, and those that were provided little indication of the physiological response of corn. No differences were observed in genes responsive to water stress or sequestering/transporting micronutrients other than zinc, indicating that these stresses were not a major component of velvetleaf competition with corn at the developmental stage tested.
Nomenclature: Velvetleaf, Abutilon theophrasti L. ABUTH; corn, Zea mays L.
