Aluminium alters mineral composition and polyphenol metabolism in leaves of tea plants (Camellia sinensis)

• Published in: Journal of inorganic biochemistry Vol. 204; p. 110956
• Main Authors: Tolrà, Roser, Martos, Soledad, Hajiboland, Roghieh, Poschenrieder, Charlotte
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-03-2020
• Subjects: Aluminum - pharmacology; Camellia sinensis - drug effects; Camellia sinensis - genetics; Camellia sinensis - metabolism; Gene Expression Profiling; Minerals - analysis; Minerals - metabolism; Plant Leaves - drug effects; Plant Leaves - genetics; Plant Leaves - metabolism; Plant Proteins - genetics; Plant Proteins - metabolism; Polyphenols - analysis; Polyphenols - metabolism; Signal Transduction; Transcriptome - drug effects
• ISSN: 0162-0134; 1873-3344
• DOI: 10.1016/j.jinorgbio.2019.110956

Tea plants (Camellia sinensis) can hyperaccumulate and tolerate high leaf concentrations of aluminium (Al). The quality of tealeaves and the positive health effects of their infusion depend on the leaf concentrations of both polyphenolic substances and mineral elements. This study explored the influence of Al supply on these leaf components under low and optimal phosphorus (P) availability. After 8 weeks exposure in hydroponics, multifactorial analysis revealed a negative influence of leaf Al on magnesium (Mg), P, boron (B), and manganese (Mn) leaf concentrations. Contrastingly, these essential mineral nutrients were positively related to leaf epigallocatechin. Galloylated catechins were positively related to leaf iron (Fe). After short-term exposure (24 and 96 h), RT-qPCR (Reverse Transcription-quantitative Polymerase Chain Reaction) analysis revealed upregulation of galloylation-related genes by substrate acidification both in old and young leaves. Only the extremely high Al accumulation in old leaves activated genes involved in biosynthesis of galloylated catechins, while in young leaves the lower Al leaf concentrations activated genes involved in anthocyanin accumulation. In conclusion, low pH and enhanced Al availability to tea plants have a strong influence on the polyphenolic pattern of tealeaves and therefore may alter both the leaves' antioxidant properties and their ability to bind Al and Fe in non-toxic form.
Multifactorial analysis using leaf concentrations of Al, selected mineral nutrients and polyphenols in tea plant. The ANS (anthocyanidin synthase) and 3GT (3-O-glucosyltransferase) gene expression, responsibles for the synthesis of anthocyanins, are upregulated (in red) by Al and P after 24 h of treatment only in young leaves. [Display omitted]
•The quality of healthy tealeaves depends on the leaf levels of polyphenols and minerals.•Leaf Al accumulation causes an upregulation of galloylation-related genes.•Galloylated catechins were positively related to leaf iron.•Al influences the leaf polyphenolic pattern and alters their antioxidant properties.