Rice phytochrome A controls apical hook opening after a single light pulse in transgenic tobacco seedlings

Abstract

SummaryApical hook opening in tobacco seedlings can be induced by a single red light pulse and this induction can be reverted by a subsequent far‐red light pulse. The slow hook opening kinetics and the reversibility of an inductive light pulse even after 8 h of darkness indicate the involvement of stable phytochrome. Compared with wild‐type, transgenic BN1 seedlings which overexpress rice phytochrome A exhibit a higher sensitivity to low irradiance red light pulses. Moreover, in BN1 seedlings an inductive red light pulse is only partially reversible even after 30 min, whereas wild‐type tobacco seedlings show complete reversibility during the entire hook opening process. The data found show that rice phytochrome A is active in transgenic tobacco seedlings in controlling hook opening and that the introduced rice phytochrome A and the endogenous stable phytochrome behave differently in this response.