Discovery of the new Coptotriche species in China revealed two novel host-plant families and host-plant orders for Tischeriidae, a family of stenophagous, leaf-mining lepidopterans

The article describes three new species of Coptotriche Walsingham, 1890 from China and adjacent northern Vietnam: C. camptotheca Xu & Dai, sp. nov. feeding on Camptotheca acuminata Decne. (Nyssaceae); C. turpinia Xu & Dai, sp. nov. feeding on Turpinia arguta (Lindl.) Seem. (Staphyleaceae); and C. asiana Diškus & Stonis, sp. nov. The latter appeared to be a narrow oligophagous species feeding on various Symplocos Jacq.: S. sumuntia Buch.-Ham. ex D. Don, S. poilanei Guill., and Symplocos glauca (Thunb.) Koidz. (Symplocaceae). Nyssaceae and Staphyleaceae are novel host-plant families of Tischeriidae. The new species are illustrated with photographs of adults, male and female genitalia, and leaf mines. The article also briefly discusses about the proportion of monophagous and oligophagous species of Tischeriidae.

A chromosome-level Camptotheca acuminata genome assembly provides insights into the evolutionary origin of camptothecin biosynthesis

Camptothecin and its derivatives are widely used for treating malignant tumors. Previous studies revealed only a limited number of candidate genes for camptothecin biosynthesis in Camptotheca acuminata, and it is still poorly understood how its biosynthesis of camptothecin has evolved. Here, we report a high-quality, chromosome-level C. acuminata genome assembly. We find that C. acuminata experiences an independent whole-genome duplication and numerous genes derive from it are related to camptothecin biosynthesis. Comparing with Catharanthus roseus, the loganic acid O-methyltransferase (LAMT) in C. acuminata fails to convert loganic acid into loganin. Instead, two secologanic acid synthases (SLASs) convert loganic acid to secologanic acid. The functional divergence of the LAMT gene and positive evolution of two SLAS genes, therefore, both contribute greatly to the camptothecin biosynthesis in C. acuminata. Our results emphasize the importance of high-quality genome assembly in identifying genetic changes in the evolutionary origin of a secondary metabolite.

Predicting Suitable Habitats of Camptotheca acuminata Considering Both Climatic and Soil Variables

Camptotheca acuminata is considered a natural medicinal plant with antitumor activity. The assessment of climate change impact on its suitable habitats is important for cultivation and conservation. In this study, we applied a novel approach to build ecological niche models with both climate and soil variables while the confounding effects between the variables in the two categories were avoided. We found that the degree-days below zero and mean annual precipitation were the most important climatic factors, while the basic soil saturation, soil gravel volume percentage, and clay content were the main soil factors, determining the suitable habitats of C. acuminata. We found that suitable habitats of this species would moderately increase in future climates under both the RCP4.5 and RCP8.5 climate change scenarios for the 2020s, 2050s, and 2080s. However, substantial shifts among levels of habitat suitability were projected. The dual high-suitable habitats would expand, which would be favorable for commercial plantations. Our findings contribute to a better understanding of the impact of climate change on this species and provide a scientific basis for the cultivation and conservation purposes.