ARS | Publication request: Transcriptome Analysis of Corn in Competition with Canola or Grown in Shade or Low Nitrogen

Submitted to: Weed Science Society of America Meeting Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: September 7, 2009
Publication Date: February 1, 2010
Citation: Hansen, S., Moriles, J., Horvath, D.P., Clay, S. 2010. Transcriptome Analysis of Corn in Competition with Canola or Grown in Shade or Low Nitrogen. Weed Science Society of America Meeting Abstracts. Presentation O(61): p.51.

Technical Abstract: The physiological mechanisms resulting in yield loss of corn due to early season stress are virtually unknown. To ascertain the relative impact of nitrogen, light, and weed stress corn was grown under optimal or stress conditions. Shade (40%) and canola (to mimic weed stress) were added at planting and removed at V4 and V8 corn growth stages with leaf samples collected for analysis at V12. Differentially expressed genes of stressed treatments clustered together, away from the control treatments. Genes from N stressed plants clustered with genes from plants where canola was removed at V4. When the weed and shade stresses were removed at V8, these genes also clustered together. Gene ontologies associated with photosynthesis and carbon usage were down-regulated in response to competition, and to a lesser frequency when shade or low N was the stressor. Sub-network analysis indicated phytochrome (PHY) A and PHYB had a role in down-regulated genes in response to competition, whereas PHYA was implicated in up-regulated gene expression in shaded plants. Zinc also played a role in up-regulated genes in response to competition. A similar response was previously observed in velvetleaf competing with corn. Ontologies associated with systemin signaling, a response usually associated with biotic stress or wound responses, were over-represented in up-regulated genes in all three stress treatments. This suggests some common stress signaling or crosstalk among stresses. Overall, the results identify both similarities and differences between responses to these three stresses.