In vivo study demonstrates inherent instability of phytochrome A mRNA in oat coleoptiles, indicating red light does not trigger transcript degradation.
Key Points
To determine whether the rapid drop in phytochrome A (phyA) mRNA levels in etiolated oat seedlings following a red light pulse is caused by light-induced destabilization or inherent transcript instability.
Measured phyA mRNA abundance and screened for putative degradation products in 4-day-old dark-grown (etiolated) oat seedlings before and after a red light pulse.
Treated oat coleoptiles with the transcriptional inhibitor cordycepin, validating synthesis inhibition via the failure of chlorophyll a/b-binding protein mRNA to accumulate following red light exposure.
Putative in vivo phyA mRNA degradation products were detected in seedlings both before and after red light irradiation.
Cordycepin treatment led to a rapid decrease in phyA mRNA abundance regardless of red light exposure, demonstrating that phyA mRNA is constitutively unstable rather than destabilized by light.