Phytochrome regulation of phytochrome A mRNA levels in the model short-day-plant Pharbitis nil.
The exposure of dark-grown Pharbitis nil seedlings to continuous R induces a rapid decrease in PHYA mRNA abundance with a half-life of about 2 h. A 5 min R pulse also induces this decline, and the effect is partially reversible by subsequent FR irradiation, confirming that the regulation of expression is mediated via the Pfr form of a phytochrome. When de-etiolated seedlings are returned to darkness after a W photoperiod, PHYA mRNA slowly reaccumulates from 20% to 50% of the dark level within 24 h. The rate of reaccumulation is greatly accelerated by the removal of Pfr with a FR pulse, resulting in reaccumulation to 100% within approximately 11 h. Without FR irradiation PHYA mRNA expression remains fully repressed for at least 11 h after the end of the photoperiod, suggesting that the controlling Pfr is highly stable.
Plant Genetics and Biotechnology Department, Horticulture Research International, Wellesbourne, Warwick, UK.
C E
CE
Carter
A
A
Szmidt-Jaworska
M
M
Hughes
B
B
Thomas
S
S
Jackson
D000595:Amino Acid Sequence; D001483:Base Sequence; D003624:Darkness; D018506:Gene Expression Regulation, Plant; D008027:Light; D008969:Molecular Sequence Data; D017440:Photoperiod; D010834:Phytochrome / Q000235:genetics / Q000378:metabolism*; D051942:Phytochrome A; D010944:Plants / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis
D051942:Phytochrome A; D012333:RNA, Messenger; D010834:Phytochrome