The rapid development of digital industries such as artificial intelligence and big data has fundamentally transformed production, providing new opportunities for the diversification of firms. Drawing on data from the China Customs Database and the Annual Survey of Industrial Firms for 2003–2013, we employed a panel fixed effects model to examine the impact of digital industry agglomeration on firms' export product diversification. The findings revealed that, holding other conditions constant, a one-unit increase in digital industry agglomeration resulted in a significant 2.34 percent rise in export scope and a significant decrease by 0.58 percent in export concentration. Firms in digitally advanced cities and capital-intensive industries were more influenced by digital industry agglomeration in export diversification. Mechanism analysis reveals that digital industry agglomeration fostered export product diversification through innovation stimulation, information dissemination, and efficiency enhancement. Innovation was evidenced by increases in urban innovation indices and the emergence of new export products. Information dissemination boosted wholesale and retail sales, helping firms to expand export destinations. Efficiency enhancement was reflected in narrowing management efficiency gaps among firms.
Plants have mechanisms to transport secondary metabolites from where they are biosynthesized to the sites where they function,or to sites such as the vacuole for detoxification.However,current research has mainly focused on metabolite biosynthesis and regulation,and little is known about their transport.Tanshinone,a class diterpenoid with medicinal properties,is biosynthesized in the periderm of Salvia miltiorrhiza roots.Here,we discovered that tanshinone can be transported out of peridermal cells and secreted into the soil environment and that the ABC transporter SmABCG1 is involved in the efflux of tanshinoneⅡA and tanshinoneⅠ.The SmABCG1 gene is adjacent to the diterpene biosynthesis gene cluster in the S.miltiorrhiza genome.The temporal–spatial expression pattern of SmABCG1 is consistent with tanshinone accumulation profiles.SmABCG1 is located on the plasma membrane and preferentially accumulates in the peridermal cells of S.miltiorrhiza roots.Heterologous expression in Xenopus laevis oocytes demonstrated that SmABCG1 can export tanshinoneⅡA and tanshinoneⅠ.CRISPR/Cas9-mediated mutagenesis of SmABCG1 in S.miltiorrhiza hairy roots resulted in a significant decrease in tanshinone contents in both hairy roots and the culture medium,whereas overexpression of this gene resulted in increased tanshinone contents.CYP76AH3 transcript levels increased in hairy roots overexpressing SmABCG1 and decreased in knockout lines,suggesting that SmABCG1 may affect the expression of CYP76AH3,indirectly regulating tanshinone biosynthesis.Finally,tanshinoneⅡA showed cytotoxicity to Arabidopsis roots.These findings offer new perspectives on plant diterpenoid transport and provide a new genetic tool for metabolic engineering and synthetic biology research.
This study examines the impact of the Belt and Road Initiative(BRI)on China's export potential at the product level.Using country–product-level data from the Centre d'Etudes Prospectives d'Informations Internationales-Base pour l'Analyse du Commerce International(CEPII-BACI),which includes 5,049 product types across 196 economies from 2007 to 2022,it explores the trade effects of the BRI and its mechanisms from the perspective of global value chains.The results indicate that the BRI has increased China's product export potential significantly to participating countires.The BRI has had the greatest impact on capital goods and labor-and capital-intensive industries.The effect has been most pronounced in China's exports to Southeast Asia,South Asia,and Europe.The mechanism analysis reveals that the BRI has improved the division of labor in the global value chains for participating countries along the BRI,strengthened China's position in their output supply chains,and stimulated the growth of China's exports.
Liang ZhangDahai FuChengjun WuYuanyuan LiuYanle Xi
