Microarray analysis was used to identify changes in gene expression in velvetleaf that result from competition with corn. The plants were grown in field plots under adequate N (addition of 220 kg N ha−1) to minimize stress and sampled at the V6 growth stage of corn (late June). Leaf area, dry weight, and N and P concentration were similar in velvetleaf plants grown alone or with corn. Competition, however, did influence velvetleaf gene expression. Genes involved in carbon utilization, photosynthesis, red light signaling, and cell division were preferentially expressed when velvetleaf was grown in competition with corn. A less clear picture of the physiological impact of growth in monoculture was provided by the data. However, several genes involved in secondary metabolism and a gene preferentially expressed in response to phosphate availability were induced. No differences were observed in genes responsive to water stress or sequestering/transporting micronutrients.
Nomenclature: Velvetleaf, Abutilon theophrasti L. ABUTH; corn, Zea mays L.; cotton, Gossypium hirsutum L.