Chromosome-level genome assembly and functional characterization of terpene synthases provide insights into the volatile terpenoid biosynthesis of Wurfbainia villosa.

Wurfbainia villosa is a well-known medicinal and edible plant that is widely cultivated in the Lingnan region of China. Its dried fruits (called Fructus Amomi) are broadly used in traditional Chinese medicine for curing gastrointestinal diseases and are rich in volatile terpenoids. Here, we report a high-quality chromosome-level genome assembly of W. villosa with a total size of approximately 2.80 Gb, 42 588 protein-coding genes, and a very high percentage of repetitive sequences (87.23%). Genome analysis showed that W. villosa likely experienced a recent whole-genome duplication event prior to the W. villosa-Zingiber officinale divergence (approximately 11 million years ago), and a recent burst of long terminal repeat insertions afterward. The W. villosa genome enabled the identification of 17 genes involved in the terpenoid skeleton biosynthesis pathway and 66 terpene synthase (TPS) genes. We found that tandem duplication events have an important contribution to the expansion of WvTPSs, which likely drove the production of volatile terpenoids. In addition, functional characterization of 18 WvTPSs, focusing on the TPS-a and TPS-b subfamilies, showed that most of these WvTPSs are multi-product TPS and are predominantly expressed in seeds. The present study provides insights into the genome evolution and the molecular basis of the volatile terpenoids diversity in W. villosa. The genome sequence also represents valuable resources for the functional gene research and molecular breeding of W. villosa.

[Study on ecological stereoscopic cultivation mode of Amomum villosum-Dimocarpus longan].

In order to set up a technical standard for planting Amomum villosum in wood forest in the future, we analyzed the relationship between the ecological factors and the yield of A. villosum planted in five Dimocarpus imocarpus longan wood forests and five miscellaneous wood forests in Yangchun city, to find out the dominant factors that affect the yield of A. villosum. The results showed that agricultural measures of fertilization, artificial irrigation and removing the old plants were positively correlated with the yield of A. villosum, the pesticide spraying and soil pH value were negatively correlated with the yield of A. villosum. But the effects of ecological factors on the yield were not significantly. High yield regions are generally located in the ravine, two sides of mountain stream and other places where water is more adequate. The slope of cultivated field with high yield is generally less than 30°, lighting and ventilation are more appropriate; soil type is generally sandy or loam, shade density is generally about 50%, and pollinators are many in quantity and variety. And we found that there was a large difference in mineral nutrient contents of soils among ten plantations. Results indicate that the yield of A. villosum is determined by the combination of each ecological factor. Suitable light intensity, moisture, ventilation and reasonable fertilization are conductive to increase the yield of A. villosum, but the use of pesticides and soil alkalization hinder the increase of A. villosum production. Too high shade density and the abuse of pesticides may be the main reason for limiting the yield of A. villosum planted in D. longan wood forests. This study has obtained key techniques of the ecological stereoscopic cultivation mode of A. villosum-D. longan, which lays a theoretical foundation for the guidance of farmers in planting A. villosum in the D. Longan forest in the future.

Synthesis of α,α-difluoromethylene alkynes by palladium-catalyzed gem-difluoropropargylation of aryl and alkenyl boron reagents.

gem-Difluoropropargyl bromides are versatile intermediates in organic synthesis, but have rarely been employed in transition-metal-catalyzed cross-coupling reactions. The first palladium-catalyzed gem-difluoropropargylation of organoboron reagents with gem-difluoropropargyl bromides is now reported. The reaction proceeds under mild reaction conditions with high regioselectivity; it features a broad substrate scope and excellent functional-group compatibility and thus provides an attractive approach for the synthesis of complex fluorinated molecules, in particular for drug discovery and development.

Nickel-catalyzed cross-coupling of functionalized difluoromethyl bromides and chlorides with aryl boronic acids: a general method for difluoroalkylated arenes.

Transition-metal-catalyzed difluoroalkylation of aromatics remains challenging despite the importance of difluoroalkylated arenes in medicinal chemistry. Herein, the first successful example of nickel-catalyzed difluoroalkylation of aryl boronic acids is described. The reaction allows access to a variety of functionalized difluoromethyl bromides and chlorides, and paves the way to highly cost-efficient synthesis of a wide range of difluoroalkylated arenes. The notable features of this protocol are its high generality, excellent functional-group compatibility, low-cost nickel-catalyst, and practicality for gram-scale production, thus providing a facile method for applications in drug discovery and development.