These are the two major questions driving research in our lab. Plants are fixed in space and therefore need to be especially flexible in their response to external stimuli.
Light is used by plants both for photosynthesis and as a developmental cue.
Multiple photoreceptors have evolved to analyze the light environment and optimize growth. Given the complexity of phytochrome and cryptochrome responses, one linear signal transduction pathway per photoreceptor is unlikely. By using genetic screens which identify early and downstream components in phytochrome and cryptochrome signal transduction, we will be able to clone and control the activity of both global regulators and genes which influence a subset of light signaling. For example, we have cloned a cytochrome P450 which can inactivate the plant steroid hormone brassinolide via hydroxylation causing light-grown plants to become dwarfs. This CYP450 acts downstream of phyA and cry1 and thus is a control point between multiple photomorphogenic pathways and hormone responses.