Relationships of Oxidative Stress and Ultraviolet-B Radiation in Plants

Plant undergoes many different stresses in life. Among the abiotic stress, UV-B radiation is a stress which causes serious threat because plants are photosynthetic and require sunlight. During photosynthesis, exposure to different extreme variations of radiations, including UV radiations, causes damage to the plants. The photosynthetic efficiency gets hindered by solar UV radiations. More than the threshold, UV-B when in excess causes damages to the biological macromolecules inside the plants including, lipids, proteins, and DNA. DNA damage leads to the changes at molecular level including gene expression. There are many UV-B targets in plants, and the main targets of UV-B are the photosynthetic machinery, and its damage is responsible for overall damage caused by the UV-B radiations. It is known that whenever UV-B stress is encountered, ROS is generated in plants that antioxidant machinery gets activated. Responses to UV-B are mediated by both nonspecific signaling pathways and specific signaling pathways. The nonspecific signaling pathways deal with DNA damage, reactive oxygen species, and defense signaling molecules whereas UV-B-specific pathways mediate photomorphogenic responses to low levels of UV-B. Under UV-B stress, there is transcriptional programming to induce the defense-related genes, which plays important roles to alleviate stress. The UV-B stress and its alleviation and associated signaling will be helpful for plant biotechnologists to develop UV-B stress-resistant plants.