The Signal Regulation Effect of UVB On Grow Lighting

Ultraviolet light UV-B is an important signal molecule, which plays a key regulatory role in the growth, metabolism and development of green plants, such as regulating photomorphogenesis (inhibiting plant elongation, promoting cotyledon opening, promoting flavonoids and cyanine Accumulation of elements to prevent stress, etc.). In the process of plants conquering the land, they have gradually evolved complex pathways for sensing and transmitting UV-B signals. UVR8 (UV RESISTANCE LOCUS 8) is currently known as the only photoreceptor in green plants that can sense UV-B radiation and transmit UV-B signals. It can complete a series of UV-B response processes by interacting with downstream transcription factors. . Nevertheless, people still have controversy about the origin and evolution history of UVR8-mediated UV-B signaling pathway in plants.

A few days ago, the team of Professor Zhong Bojian from Nanjing Normal University published an online research paper entitled Origin and adaptive evolution of UV RESISTANCE LOCUS 8-mediated signaling during plant terrestrialization in Plant Physiology, which systematically explained the origin and Evolution history. The study clarified the origin groups of different UV-B signaling pathways in plants, and revealed that green plants gradually evolved different UV-B signaling pathways to adapt to the changing UV-B environment of the land.

The researchers first used comparative genomics and phylogenetic methods to analyze the core elements of the UV-B signaling pathway in 79 representative plant genomes, and found that the UV-B receptor UVR8 presents a very conservative evolutionary history. The downstream negative regulatory factors and transcription factors present a different evolutionary course from that of green plants. The classic UVR8-COP1/SPA-HY5-RUP signaling pathway in plants originated from green algae. The origin of this signaling pathway gives green plants the ability to respond to UV-B radiation. Phylogenetic analysis showed that elements such as BES1/BIM1, WRKY36, MYB73/MYB77 and PIFs originated from chara, and MYB13 originated from angiosperm ancestor group.

The study also found evidence related to the adaptation of plants to the strong UV-B environment on land in groups such as green algae, chara, and moss, including positive selection signals in UVR8 and RUPs and an increase in the number of copies of downstream transcription factors. In addition, the use of protein interaction experiments found that UVR8 interacts with BIM1, WRKY36, MYB73/MYB77 in early land plant liverwort, which further supports UVR8-BES1/BIM1, UVR8-WRKY36-HY5 and UVR8-MYB73/MYB77. The guided UV-B signaling pathway originated from early land plants. Transcription factors such as BES1/BIM1, WRKY36, MYB73/MYB77 and PIFs are key regulatory elements of the hormone signaling pathway. Studies have shown that the establishment of these UVR8-mediated signaling pathways provides the basis for the connection between UV-B signaling and plant endogenous hormones.

To sum up, in the process of plant terrestrialization, the classic UVR8-COP1/SPA-HY5-RUP signal pathway has undergone adaptive changes, which promotes green plants to conduct UV-B signal transduction in the terrestrial strong UV-B environment. Physiological response. At the same time, green plants have also evolved diversified UV-B signal transduction and interaction mechanisms with plant endogenous hormones, expanding their UV-B signal transduction pathways, and providing them to adapt to the changing UV-B radiation environment on land. Base. This research system reveals the origin and evolution history of the core components of plant UV-B signal transduction, and provides a theoretical reference for in-depth understanding of the molecular mechanisms of plants adapting to UV-B stress.

Dr. Zhang Zhenhua from the School of Life Sciences, Nanjing Normal University is the first author, and Professor Zhong Bojian is the corresponding author. Researchers Shi Chen and Liu Hongtao, PhD candidates from the Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, participated in the research work. This research was funded by the National Natural Science Foundation of China and the Biological Advantages of Jiangsu Province.