UV RESISTANCE LOCUS8 (UVR8) signaling involves CONSTITUTIVELY PHOTOMORPHOGENIC1, the ELONGATED HYPOCOTYL5 (HY5) transcription factor, and the closely related HY5 HOMOLOG. Some UV-B responses mediated by UVR8 are also regulated by nitric oxide (NO), a bioactive molecule that orchestrates a wide range of processes in plants. In this study, we investigated the participation of the UVR8 pathway and...

The E3 ubiquitin ligase COP1 (CONSTITUTIVE PHOTOMORPHOGENIC1) plays a key role in the repression of the plant photomorphogenic development in darkness. In the presence of light, COP1 is inactivated by a mechanism which is not completely understood. This leads to accumulation of COP1's target transcription factors, which initiates photomorphogenesis, resulting in dramatic changes of the seedling...

Exposure to high irradiance results in dramatic changes in nuclear gene expression in plants. However, little is known about the mechanisms by which changes in irradiance are sensed and how the information is transduced to the nucleus to initiate the genetic response. To investigate whether the photoreceptors are involved in the response to high irradiance, we analyzed expression of EARLY LIGHT...

Although plants are autotrophs, they don’t start out that way. During early plant growth, reserves stored by the mother plant are mobilized to provide the seedling with energy and carbon until the switch to autotrophic growth occurs (Chen and Thelen, 2010). This crucial developmental switch involves light signal transduction and the production of reactive oxygen species (ROS), including singlet...

Plants don’t go into the light as a near-death experience—the plant’s complex response to light begins before the seedling even emerges. For example, in many plant species, red (R) light promotes germination and far-red (FR) light inhibits germination. Indeed, because chlorophyll absorbs R light, a high ratio of R:FR indicates direct sunlight and a low ratio indicates shade from other leaves; p...

44 Plants have evolved an intricate network of sensory photoreceptors and signalling components 45 to regulate their development. Among the light signalling components identified till date, HY5, a 46 bZIP transcription factor, has been investigated extensively. However, most of the work on HY5 47 www.plantphysiol.org on August 25, 2017 Published by Downloaded from Copyright © 2017 American Soci...

The E3 ubiquitin ligase COP1 (CONSTITUTIVE PHOTOMORPHOGENIC1) plays a key role in the repression of the plant photomorphogenic development in darkness. In the presence of light, COP1 is inactivated by a mechanismwhich is not completely understood. This leads to accumulation of COP1’s target transcription factors, which initiates photomorphogenesis, resulting in dramatic changes of the seedling’...

Karrikins are a class of seed germination stimulants identified in smoke from wildfires. Microarray analysis of imbibed Arabidopsis thaliana seeds was performed to identify transcriptional responses to KAR(1) before germination. A small set of genes that are regulated by KAR(1), even when germination is prevented by the absence of gibberellin biosynthesis or light, were identified. Light-induce...

The synergism between red and blue light in the control of plant growth and development requires the coaction of the red light photoreceptor phytochrome B (phyB) and the blue light and UV-A receptor cryptochromes (cry). Here, we describe the mechanism of the coaction of these photoreceptors in controlling both development and physiology. In seedlings grown under red light, a transient supplemen...