Affiliation:
1. State Key Laboratory of Hybrid Rice, College of Life Sciences Wuhan University Wuhan 430072 China
2. Yunnan Baotian Agricultural Technology Co., Ltd Kunming 650101 China
3. Department of Botany, National Museum of Natural History Smithsonian Institution Washington 20013‐7012 DC USA
Abstract
SUMMARYSteroidal saponins are a class of specialized metabolites essential for plant's response to biotic and abiotic stresses. They are also important raw materials for the industrial production of steroid drugs. Steroidal saponins are present in some monocots, such as Dioscorea and Paris, but their distribution, origin, and evolution in plants remain poorly understood. By reconstructing the evolutionary history of the steroidal saponin‐associated module (SSAM) in plants, we reveal that the steroidal saponin pathway has its origin in Asparagus and Dioscorea. Through evaluating the distribution and evolutionary pattern of steroidal saponins in angiosperms, we further show that steroidal saponins originated multiple times in angiosperms, and exist in early diverged lineages of certain monocot lineages including Asparagales, Dioscoreales, and Liliales. In these lineages, steroidal saponins are synthesized through the high copy and/or high expression mechanisms of key genes in SSAM. Together with shifts in gene evolutionary rates and amino acid usage, these molecular mechanisms shape the current distribution and diversity of steroidal saponins in plants. Consequently, our results provide new insights into the distribution, diversity and evolutionary history of steroidal saponins in plants, and enhance our understanding of plants' resistance to abiotic and biotic stresses. Additionally, fundamental understanding of the steroidal saponin biosynthesis will facilitate their industrial production and pharmacological applications.
Funder
National Natural Science Foundation of China
Subject
Cell Biology,Plant Science,Genetics