Elevated Ozone Levels Affect Metabolites and Related Biosynthetic Genes in Tartary Buckwheat.

Global climate change and the industrial revolution have increased the concentration of tropospheric ozone, a photochemical air pollutant that can negatively affect plant growth and crop production. In the present study, we investigated the effects of O-3 on the metabolites and transcripts of tartary buckwheat. A total of 36 metabolites were identified by gas chromatography coupled with time-of-flight mass spectrometry, and principal component analysis was performed to verify the metabolic differences between nontreated and O-3 -treated tartary buckwheat. The content of threonic acid increased after 2 days of the O-3 treatment, whereas it decreased after 4 days of exposure, after which it gradually increased until the eighth day of exposure. In addition, the levels of most metabolites decreased significantly after the O-3 treatment. On the contrary, the levels of two anthocyanins, cyanidin-3-O-glucoside and cyanidin-3-O-rutinoside, increased more than 11.36- and 11.43-fold, respectively, after the O-3 treatment. To assess the effect of O-3 on the genomic level, we analyzed the expression of anthocyanin biosynthesis pathway genes in O-3-treated and nontreated buckwheat using quantitative real-time reverse transcription polymerase chain reaction (PCR). We found that the expression of all anthocyanin pathway genes increased significantly in the O-3-treated buckwheat compared to that in the nontreated buckwheat. Altogether, our results suggested that O-3 affected the transcripts and metabolites of tartary buckwheat, which would eventually cause phenotypic changes in plants.