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We found triptolide synthesis is correlated with the expressions of TwGGPPS1 and TwGGPPS4 . This lays the foundation for future studies of biosynthetic pathways for triptolide and other diterpenoids in T. wilfordii. Tripterygium wilfordii is a traditional Chinese medical plant commonly used to treat rheumatoid arthritis. One of its main bioactive compounds is triptolide, which is identified as an abietane-type diterpenoid natural product. Geranylgeranyl diphosphate synthase (GGPPS) catalyses the synthesis of GGPP (geranylgeranyl diphosphate), the common precursor of diterpenes, and is therefore a crucial enzyme in diterpene biosynthesis. A previous study showed that GGPP could be catalyzed by copalyl diphosphate synthase and kaurene synthase like of Salvia miltiorrhiza (SmCPS, SmKSL) to miltiradiene, a key intermediate in tanshinone biosynthesis. In this paper, five new full-length cDNAs (TwGGPPS) encoding GGPP synthases were cloned from T. wilfordii. Sequence comparisons revealed that all six TwGGPPSs (including TwGGPPS2 cloned previously) exhibit similarities to GGPPSs of other plants. Subsequent functional complement assays demonstrated that TwGGPPS1, TwGGPPS4 and TwGGPPS5 can participate in miltiradiene biosynthesis in the recombinant E. coli. Correlation analysis of gene expressions and secondary metabolite accumulation indicated that TwGGPPS1 and TwGGPPS4 are likely involved in the biosynthesis of triptolide. These findings lay the foundation for future studies of the biosynthetic pathways for triptolide and other diterpenoids in T. wilfordii.

The objective of this study was to establish a real-time LAMP assay for authentication of rape (Brassica napus) honey to protect consumers from commercial honey adulteration. The LAMP primers targeting the internal transcribed spacer (ITS) of Brassica napus were designed, and its specificity was tested. The LAMP reaction temperature was also optimized, and the detection limit of the LAMP assay was determined with a serial dilution of genomic DNA from the seeds of Brassica napus. The results showed that the real-time LAMP assay can accurately and specifically detect the rape component in honey, and the detection limit was 10 pg genomic DNA of Brassica napus. Data on monofloral honey samples indicate that the real-time LAMP assay was 100% in concordance with the reported TaqMan TM PCR assay. This study provides a promising solution for facilitating the authentication of rape honey in food retail market.Desarrollo de un ensayo LAMP en tiempo real para la autenticación de la miel monofloral utilizando miel de colza RESUMEN El presente estudio se propuso establecer un ensayo LAMP en tiempo real destinado a autenticar la miel de colza (Brassica napus) para proteger a los consumidores de la adulteración comercial de la miel. Con esta finalidad se diseñaron cebadores LAMP dirigidos al espaciador transcrito interno (ITS) de Brassica napus y se probó su especificidad. Además, se optimizó la temperatura de reacción del LAMP, determinándose el límite de detección del ensayo LAMP con una dilución en serie de ADN genómico de las semillas de Brassica napus. Los resultados mostraron que dicho ensayo en tiempo real puede detectar con precisión y especificidad el componente de colza en la miel; el límite de detección fue de 10 pg de ADN genómico de Brassica napus. Los datos obtenidos de las muestras de miel monofloral dan cuenta de que el ensayo LAMP en tiempo real concordaba al 100% con el ensayo de PCR TaqMan TM notificado. Este estudio ofrece una solución prometedora para facilitar la autenticación de la miel de colza en el mercado minorista de alimentos.

The non-farming use of cropland has led to food insecurity in China due to drastic land use (LU) changes under the stresses of ecological restoration and urbanization, particularly in non-major grain-producing areas. Questions were raised about spatiotemporal cropland losses/gains and their drivers in these areas in the future for sustainable development of the agriculture sector. However, the answers to these questions have not been well acknowledged. This study, therefore, presents analyses of cropland area change from 1990 to 2018 and from 2018 to 2051 in Shaanxi province based on the Future Land Use Simulation (FLUS) model that follows the integration of the Shared Socioeconomic Pathway 2 and the Representative Concentration Pathway 4.5 (SSP245) within the International Coupled Model Intercomparison Project 6 (CMIP6). The results highlight that ecological restoration and fast-paced urbanization mainly drove the alarming non-farming use of cropland. The per capita cropland area is projected to increase, but the cropland loss will still occur, which potentially causes food insecurity. Thus, food security will be a challenging issue in the near future. The quantitative findings call for careful designs of LU policies, taking into account cropland protection, socio-economic development, and ecological restoration.