Light signaling and UV-B mediated plant growth regulation.

Light plays an important role in plants' growth and development throughout their life cycle. Plants alter their morphological features in response to light cues of varying intensity and quality. Dedicated photoreceptors help plants to perceive light signals of different wavelengths. Activated photoreceptors stimulate the downstream signaling cascades that leads to extensive gene expression changes responsible for physiological and developmental responses. Proteins such as ELONGATED HYPOCOTYL5 (HY5) and CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) act as important factors that modulate light-regulated gene expression, especially during seedling development. These factors function as central regulatory intermediates not only in red, far-red and blue light pathways but also in the UV-B signaling pathway. UV-B radiation makes up only a minor fraction of sunlight, yet it imparts many positive and negative effects on plant growth. Studies on UV-B perception, signaling and response in plants has considerably surged in recent times. Plants have developed different strategies to use UV-B as a developmental cue as well as to withstand high dose of UV-B radiation. Plants' response to UV-B is an integration of its crosstalks with both environmental factors and phytohormones. This review outlines the current developments in light signaling with a major focus on UV-B mediated plant growth regulation. This article is protected by copyright. All rights reserved.