Maruhnich, Stefanie , Kumar, Dibyendu , Dhingra, Amit , Folta, Kevin M. .
Green Light Antagonizes Phytochrome and Cryptochrome Responses in Developing Seedlings.
Light quality, quantity, and duration influence developmental processes during seedling establishment. A rich history describes how red, blue and far-red light control processes associated with this developmental transition, such as inhibition of hypocotyl elongation and increase in plastid transcripts required for photosynthesis. Our laboratory has demonstrated specific effects of narrow-bandwidth green light that are genetically and photophysiologically discrete from known sensory systems. In this study we expand these findings and present evidence that green light signals balance the developmental effects induced by red and/or blue light acting through the phytochrome and cryptochrome systems. Co-irradiation with red, blue and green light using our specialized LED chambers indicates that the addition of green wavebands can conditionally reverse hypocotyl growth inhibition and affect leaf development driven by blue and/or red light. Green light also affects phytochrome-induced gene expression. Dark-grown seedlings were treated with a short, single pulse of red light, a pulse of dim green light (1/500th the fluence of red, approximately “safelight” fluence rates), or a combination of both treatments. Northern analyses show that the minor green treatment can reduce, if not negate, red-induced transcript accumulation. The effects of green light are apparent only during specific windows in seedling development. Together, these data support a hypothesis that a novel green light sensing system works carefully in concert with known sensory systems to optimize seedling morphology and physiology during establishment.
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1 - University of Florida, Plant Molecular and Cellular Biology Program, Horticultural Sciences Department, 1301 Fifield Hall, Gainesville, FL, 32611, US
2 - University of Florida, Horticultural Sciences Department
3 - Washington State University, Horticultural and Landscape Architecture Department
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM