Journal Article Epublish
PubMed: 42079446 DOI: 10.1002/mlf2.70075
Osmotic signaling governs sunscreen biosynthesis to safeguard desert cyanobacteria against desiccation.
mLife 5(2):164-179
Authors: Lei Zhao, Hai-Feng Xu, Jin-Long Shang, Yong Li, Xiao-Yue Yin, Zhong-Chun Zhang, Huazhong Shi, Bao-Sheng Qiu
Affiliations
- School of Life Sciences, Key Laboratory of Pesticide & Chemical Biology of Ministry of Education, Hubei Key Laboratory of Genetic Regulation and Integrative Biology, Central China Normal University Wuhan Hubei China.
- Department of Chemistry and Biochemistry Texas Tech University Lubbock Texas USA.
Abstract
Mycosporine-like amino acids (MAAs) are natural sunscreens synthesized by a wide range of organisms. Although the induction of MAA production by ultraviolet radiation is well established, the signaling pathways involved and specific functions of MAAs under other stress conditions remain poorly understood. We demonstrated that MAAs serve as effective osmoprotectants for desiccation tolerance in the desert cyanobacterium Nostoc flagelliforme. Genetic disruption of genes encoding MAA biosynthetic enzymes eliminated MAA production, resulting in elevated oxidative damage, increased lipid peroxidation, and impaired photosynthesis under dehydration. Biochemical assays revealed that MAAs stabilize proteins and scavenge reactive oxygen species, indicating dual roles as osmolytes and antioxidants. Furthermore, we identified a signaling pathway Dsp1-OrrA that mediates the osmotic induction of MAA biosynthesis. Genetic disruption of either gene of Dsp1 and OrrA abolished osmotic induction and severely reduced desiccation tolerance. Phylogenomic analysis suggests that MAA biosynthesis is an ancient trait conserved in desiccation-tolerant cyanobacteria. This work deepens our understanding of microbial adaptation to extreme environments and provides a foundation for synthetic biology applications of MAAs.
MeSH
Genes, Cyanobacteria, Sunscreening Agents