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Sweetpotato (Ipomoea batatas [L.] Lam.) stem tips, which contain high concentrations of chlorogenic acid (CGA), are useful as a physiologically functional food to protect against some serious diseases. According to previous studies, exogenous application of phytohormones may be an effective agrotechnical measure to control CGA biosynthesis through the transcriptional regulation of pathway gene expressions. To understand the mechanism of CGA biosynthesis in sweetpotato, we investigated the effects of exogenous phytohormones on CGA metabolism in stem tips of sweetpotato. A significantly elevated CGA content was observed in salicylic acid (SA)-treated sweetpotato stem tips at 72 h, as well as in those subjected to abscisic acid (ABA) or gibberellic acid (GA) treatments. Dynamic expression change of seven enzyme genes involved in sweetpotato CGA biosynthesis were analyzed to determine correlations between transcript levels and CGA accumulation. As revealed by the differential expression of these genes under distinct phytohormone treatments, the regulation of specific pathway genes is a critical determinant of the accumulation of CGA in sweetpotato stem tips. We also found that several hormone-responsive sites, such as those for ABA, GA, SA, and jasmonic acid (JA), were present in the promoter regions of sweetpotato CGA biosynthestic pathway genes. Collectively, phytohormones can regulate the transcription of CGA synthesis-related genes and ultimately affect CGA accumulation in sweetpotato stem tips, whereas the regulatory differences are mirrored by cis-acting elements in the corresponding pathway gene promoters.

Sweetpotato [Ipomoea batatas (L.) Lam.], a food crop with both nutritional and medicinal uses, plays essential roles in food security and health-promoting. Chlorogenic acid (CGA), a polyphenol displaying several bioactivities, is distributed in all edible parts of sweetpotato. However, little is known about the specific metabolism of CGA in sweetpotato. In this study, IbPAL1, which encodes an endoplasmic reticulum-localized phenylalanine ammonia lyase (PAL), was isolated and characterized in sweetpotato. CGA accumulation was positively associated with the expression pattern of IbPAL1 in a tissue-specific manner, as further demonstrated by overexpression of IbPAL1. Overexpression of IbPAL1 promoted CGA accumulation and biosynthetic pathway genes expression in leaves, stimulated secondary xylem cell expansion in stems, and inhibited storage root formation. Our results support a potential role for IbPAL1 in sweetpotato CGA biosynthesis and establish a theoretical foundation for detailed mechanism research and nutrient improvement in sweetpotato breeding programs.

Polypropylene plastic (PP) was chosen as additives for the preparation of activated carbon (AC), considering that PP promotes pore formation during the preparation of AC. When the addition ratio of PP was 20%, AC having a maximum specific surface area of 1916.1 m2/g was prepared. Fourier transform–infrared spectroscopy (FT-IR) analysis exhibited the types of functional groups on the surface of AC, such as–OH, C=O, C–C, and–CH. The SEM analysis revealed the formation of disordered pores over the AC. Furthermore, iodine value of the AC is 1460 mg/g. Additionally, adsorption test revealed the AC is suitable for adsorbing methylene blue (MB). The adsorption equilibrium data of MB onto AC were most suitable for Redlich–Peterson model. The maximum adsorption capacity of the single layer was 476.88 mg/g, indicating that AC has high adsorption capacity. The kinetic data fitted well with the pseudo-second-order model.