Phytochrome Control of Specific mRNA Levels in Developing Pea Buds

Abstract

We have examined phytochrome regulated changes in transcript abundance for 11 different light regulated mRNAs in developing pea buds. Fluence-response curves were measured for changes in transcript abundance in response to red light pulses in both the low and very low fluence ranges. Most transcripts show only low fluence responses, with a threshold of approximately 10 micromoles per square meter. All of the low fluence responses are reversible by far red light. One transcript shows a very low fluence response, with a threshold of approximately 10⁻⁴ micromoles per square meter. As expected, the very low fluence response is not far red reversible and in fact can be induced by far red light.