Project description:We sought to determine the transcriptomic impacts of artemisinin, Artemisia annua extract, and Artemisia afra extract on M. tuberculosis. Log phase cultures were treated with lethal doses for four hours or with inhibitory or sub-inhibitory doses for 24 hours. RNA was collected from untreated controls at the same timepoint.
Project description:Artemisia annua is known to produce the antimalarial phytomolecule artemisinin. The seedling and mature leaf of the plant represent two contrasting tissues in terms of their artemisinin content. The major objective of the present study was to use a small-scale (750 target genes) microarray of A. annua for identification of genes that are differentially expressed in the seedling and mature leaf tissues of the plant.
Project description:Purpose: UV-B radiation is a pivotal photomorphogenic signal and positively regulates plant growth and metabolite biosynthesis. In order to elucidate the transcriptional regulation mechanism underlying UV-B-induced artemisinin and flavonoid biosynthesis in Artemisia annua, the transcriptional response of A. annua leaves to UV-B radiation was analyzed using the Illumina transcriptome sequencing. Methods: For UV-B treatment, six-week-old A. annua seedlings growing under normal growth condition were supplemented with extra narrowband UV-B lamps (Philips TL20W/01RS; 1.5 μmol·m-2·s-1)(Yin et al. 2016). The most recently expanded leaf for each A. annua seedling was collected at 0, 2, 4 and 6 hours after exposure to UV-B radiation. Results: A total of 10706 differentially expressed genes including 533 transcription factors, were identified. Based on the expression trends of the differentially expressed factors as well as artemisinin and flavonoid biosynthesis genes, we speculated that transcription factors belonging to 6 clusters were most likely to be involved in the regulation of artemisinin and/or flavonoid biosynthesis. The regulatory relationship between transcription factors and artemisinin/flavonoid biosynthetic genes was further studied. Dual-LUC assays results showed that AaMYB6 is a positive regulator of AaLDOX, which belongs to flavonoid biosynthesis pathway. In addition, we identified a R2R3MYB transcription factor, AaMYB4 which positively mediated both artemisinin and flavonoid biosynthesis pathways by activating the expression of AaADS and AaDBR2 in artemisinin biosynthesis pathway and AaUFGT in flavonoid biosynthesis pathway. Conclusions: our findings provide fundamental knowledge for the further analysis of the parallel transcriptional regulation of artemisinin and flavonoid biosynthesis in A. annua L. under UV-B radiation.
