Plants become photosynthetic through de-etiolation, a developmental process regulated by red/far-red light-absorbing phytochromes and blue/ultraviolet A light-absorbing cryptochromes. Genetic screens have identified i...Plants become photosynthetic through de-etiolation, a developmental process regulated by red/far-red light-absorbing phytochromes and blue/ultraviolet A light-absorbing cryptochromes. Genetic screens have identified in the last decade many far-red light signaling mutants and several red and blue light signaling mutants, suggesting the existence of distinct red, far-red, or blue light signaling pathways downstream of phytochromes and cryptochromes. However, genetic screens have also identified mutants with defective de-etiolation responses under multiple wavelengths. Thus, the opti- mal de-etiolation responses of a plant depend on coordination among the different light signaling pathways. This review intends to discuss several recently identified signaling components that have a potential role to integrate red, far-red, and blue light signalings. This review also highlights the recent discoveries on proteolytic degradation in the desensitization of light signal transmission, and the tight connection of light signaling with photoperiodic flowering and circadian rhythm. Studies on the controlling mechanisms of de-etiolation, photoperiodic flowering, and circadian rhythm have been the fascinating topics in Arabidopsis research. The knowledge obtained from Arabidopsis can be readily applied to food crops and ornamental species, and can be contributed to our general understanding of signal perception and transduction in all organisms.展开更多
Phytochrome has fascinated plant scientists since its discovery in 1959-1960 by the Beltsville research group of the United States Department of Agriculture. Studies in the first 20 years had evidenced that phytochrom...Phytochrome has fascinated plant scientists since its discovery in 1959-1960 by the Beltsville research group of the United States Department of Agriculture. Studies in the first 20 years had evidenced that phytochrome acts as an universal regulator in plant life adapting its behavior to the environmental light, and developed widely the physiological understanding of phytochrome action. In the following 20 years, some thirty world_wide major laboratories have published over two hundred papers a year on various aspects of the subject, and they are making steady progress. The authors’ work has also contributed to the following aspects: coaction of phytochrome and phytohormone in photomorphogenesis, phytochrome purification, phytochrome regulation of male fertility, as well as phytochrome A gene analysis and expression in photoperiod sensitive genic male sterile rice. In the recent decade significant advances have been made in studies on phytochrome molecules, genes and signal transduction in phytochrome response. This is largely due to the advances in molecular genetics, where experiments using mutants and transgenic plants, particularly in Arabidopsis, that have led to the significant insights at the molecular level. The topics in this review include:(1) Discovery of phytochrome; (2) Functions of phytochrome; (3) Phytochrome molecules; (4) Phytochrome regulation in gene expression.展开更多
文摘Plants become photosynthetic through de-etiolation, a developmental process regulated by red/far-red light-absorbing phytochromes and blue/ultraviolet A light-absorbing cryptochromes. Genetic screens have identified in the last decade many far-red light signaling mutants and several red and blue light signaling mutants, suggesting the existence of distinct red, far-red, or blue light signaling pathways downstream of phytochromes and cryptochromes. However, genetic screens have also identified mutants with defective de-etiolation responses under multiple wavelengths. Thus, the opti- mal de-etiolation responses of a plant depend on coordination among the different light signaling pathways. This review intends to discuss several recently identified signaling components that have a potential role to integrate red, far-red, and blue light signalings. This review also highlights the recent discoveries on proteolytic degradation in the desensitization of light signal transmission, and the tight connection of light signaling with photoperiodic flowering and circadian rhythm. Studies on the controlling mechanisms of de-etiolation, photoperiodic flowering, and circadian rhythm have been the fascinating topics in Arabidopsis research. The knowledge obtained from Arabidopsis can be readily applied to food crops and ornamental species, and can be contributed to our general understanding of signal perception and transduction in all organisms.
文摘Phytochrome has fascinated plant scientists since its discovery in 1959-1960 by the Beltsville research group of the United States Department of Agriculture. Studies in the first 20 years had evidenced that phytochrome acts as an universal regulator in plant life adapting its behavior to the environmental light, and developed widely the physiological understanding of phytochrome action. In the following 20 years, some thirty world_wide major laboratories have published over two hundred papers a year on various aspects of the subject, and they are making steady progress. The authors’ work has also contributed to the following aspects: coaction of phytochrome and phytohormone in photomorphogenesis, phytochrome purification, phytochrome regulation of male fertility, as well as phytochrome A gene analysis and expression in photoperiod sensitive genic male sterile rice. In the recent decade significant advances have been made in studies on phytochrome molecules, genes and signal transduction in phytochrome response. This is largely due to the advances in molecular genetics, where experiments using mutants and transgenic plants, particularly in Arabidopsis, that have led to the significant insights at the molecular level. The topics in this review include:(1) Discovery of phytochrome; (2) Functions of phytochrome; (3) Phytochrome molecules; (4) Phytochrome regulation in gene expression.
