Assessing environmental suitability of Ligusticum chuanxiong based on ecological analyses with chemical and molecular verification

Ligusticum chuanxiong Hort. as an important Chinese medicinal herb clinically used as anti-inflammatory, antioxidant, and hepatoprotective agents, is widely planted in China. However, related studies on L. chuanxiong's distribution and significant environmental factors that affect its growth are insufficient. Based on climatic, topographic and soil factors, this study predicted current and future distributions of L. chuanxiong and analyzed the distribution transformation under different scenarios. Moreover, the most important environmental factors for modeling were explored using maximum entropy models, chemical analysis and molecular analysis. Results suggested that the predicted distribution of L. chuanxiong was wider than previously reported. Among these environmental variables, climate factors, especially the minimum temperature of the coldest month (Bio6, 46.7%) and solar radiation (SRAD, 43.4%) contributed more than others to L. chuanxiong's distribution with optimum values of 0-1.5 °C and 5000-11,000 kJ/m2 per day. Total and highly suitable areas respectively increased by 26,788-943,820 km2 and 34,757-340,417 km2 in the future (2061-2080, 2081-2100). The distribution centers of suitable zones were predicted to migrate north in the future, and the migration distance was 135.74-479.77 km from current center. Results of chemical content determination suggested that L. chuanxiong should be cultivated in high-suitable places to improve medicinal quality by evaluating contents of ferulic acids and Z-ligustilide. Correlation analysis suggested that both chemical contents and gene expression levels decreased with decreasing habitat suitability, suggesting a strong link between environments, chemical constituents, and gene expression. These findings improve the comprehension of the effects of environments on the distribution patterns of L. chuanxiong, as well the relation between environmental suitability and medicinal quality. These findings provide a useful foundation for the planting, cultivation and conservation of L. chuanxiong.