Zingiberaceae plants are distributed in the tropical and subtropical regions of the world, being used in many famous medicinal materials. Meanwhile, some Zingiberaceae plants are important horticultural flowers because they are green all year round and have special aromas. To conduct an extensive investigation of the resources of Zingiberaceae plants, the volatile compounds of ten species of Zingiberaceae were extracted and analyzed by GC–MS, including Costus comosus var. bakeri (K.Schum.) Maas, Curcuma rubescens Roxb., Curcuma aeruginosa Roxb., Curcuma attenuata Wall., Hongfengshou, Hedychium coronarium Koeng, Zingiber zerumbet (L.) Smith, Hedychium brevicaule D. Fang, Alpinia oxyphylla Miq., and Alpinia pumila Hook.F. A total of 162 compounds were identified, and most of those identified were monoterpenes and sesquiterpenes. (E)-labda-8(17),12-diene-15,16-dial, n-hexadecanoic acid, 4-methoxy-6-phenethyl-2H-pyran-2-one, and L-β-pinene were found in high concentrations among the plants. These ten species of Zingiberaceae contained some of the same volatiles, but their contents were different. Pharmacological effects may be associated with the diversity of volatiles in these ten plants.

Amomum tsao-ko is an economically important spice plant in the ginger family (Zingiberaceous). The dried ripe fruit has been widely used as spice and medicine in Southeast Asia due to its distinct flavor metabolites. However, there is little genomic information available to understand the biosynthesis of its characteristic flavor compounds. Here, we present a high-quality chromosome-level genome of A. tsao-ko with a total length of 2.08 Gb assembled into 24 chromosomes. Potential relationships between genetic variation and chemical constituents were analyzed by genome-wide association study (GWAS) of 119 representative A. tsao-ko specimens in China. Metabolome and transcriptome correlation analysis of different plant organs and fruit developmental stages revealed the proposed biosynthesis of the characteristic bicyclononane aldehydes and aromatic metabolites in A. tsao-ko fruit. Transcription factors of 20 families may be involved in the regulatory network of terpenoids. This study provides genomic and chemical insights into the biosynthesis of characteristic aroma and flavor constituents, which can be used to improve the quality of A. tsao-ko as food and medicine.

BACKGROUND Portulaca oleracea L., common purslane, is an insecticidal plant that has been documented as a ‘Chinese indigenous pesticide’, and it is seldom visited by insects in the field. However, identification of anti‐insect compounds and mechanisms of action are still unclear. RESULTS Interplanting purslane with Chinese cabbage demonstrated that purslane may contain secondary compounds that S. litura avoids eating. Four compounds were isolated from P. oleracea by directed anti‐insect activity, and their chemical structures were identified by NMR spectra as (9Z,11E,15Z)‐13‐hydroxyoctadeca‐9,11,15‐trienoic acid (1), portulacanone A (2), portulacanone D (3), and a new natural product 2,4′‐dihydroxy‐3′,5′‐dimethoxychalcone (4). A combination of compound 1 and 2 possessed stronger activity than other combinations (compounds 1 + 3; 1 + 4; 2 + 3; 2 + 4; 3 + 4). Both active compounds were detected in all samples from 23 regions in China, and concentrations in samples collected from 17 regions were generally above 500 μg/kg. Concentrations of compounds 1 and 2 fluctuated greatly from April to November, and reached maximum concentrations of 45 951.44 μg/kg for compound 1 and 3739.09 μg/kg for compound 2 in November. The combination of these compounds (1 + 2) caused mid‐gut structural deformation and tissue decay as determined by mid‐gut histopathology of S. litura. CONCLUSION In general, these active compounds coexisting contributed to partly protect purslane from insects. This research also provides new insights into the use of purslane as important ingredient of botanical pesticide alternatives to traditional chemical pesticides. © 2019 Society of Chemical Industry