AUTHOR=Kayani Sadaf-Ilyas , Shen Qian , Ma Yanan , Fu Xueqing , Xie Lihui , Zhong Yijun , Tiantian Chen , Pan Qifang , Li Ling , Rahman Saeed-ur , Sun Xiaofen , Tang Kexuan 

TITLE=The YABBY Family Transcription Factor AaYABBY5 Directly Targets Cytochrome P450 Monooxygenase (CYP71AV1) and Double-Bond Reductase 2 (DBR2) Involved in Artemisinin Biosynthesis in Artemisia Annua

JOURNAL=Frontiers in Plant Science

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.01084

DOI=10.3389/fpls.2019.01084

ISSN=1664-462X

ABSTRACT=<p>Artemisinin is an effective antimalarial sesquiterpene lactone synthesized in <italic>Artemisia annua</italic>. Various transcription factors have been previously reported that can influence the biosynthesis of artemisinin; however, the effect of YABBY family transcription factors on artemisinin biosynthesis was unknown. In the present study, we cloned and characterized AaYABBY5: a homolog of MsYABBY5 in <italic>Mentha spicata</italic> which is involved in modulating the monoterpenes, as a positive regulator of artemisinin biosynthesis in <italic>A. annua</italic>. AaYABBY5 was found localized to the nucleus, and its expression was found to be induced by exogenous methyl jasmonic acid (MeJA) treatment. In the dual-luciferase reporter assay, it was found that AaYABBY5 significantly increased the activities of promoters of amorpha-4,11-diene synthase (<italic>ADS</italic>), cytochrome P450 monooxygenase (<italic>CYP71AV1</italic>), double-bond reductase 2 (<italic>DBR2</italic>), and aldehyde dehydrogenase 1 (<italic>ALDH1</italic>) genes. Yeast one hybrid assay showed that AaYABBY5 directly bonds to the promoters of <italic>CYP71AV1</italic> and <italic>DBR2</italic> genes. Quantitative real-time polymerase chain reaction (qPCR) of <italic>AaYABBY5</italic> overexpression and <italic>AaYABBY5</italic> antisense plants revealed a significant increase in the expression of <italic>ADS</italic>, <italic>CYP71AV1</italic>, <italic>DBR2</italic>, and <italic>ALDH1</italic> in <italic>AaYABBY5</italic> overexpression plants and a significant decrease in the expression of these genes in <italic>AaYABBY5</italic> antisense <italic>A. annua</italic>, respectively. Furthermore, the results of high-performance liquid chromatography (HPLC) showed that the artemisinin and its precursor dihydroartemisinic acid were significantly increased in the <italic>AaYABBY5</italic> overexpression plants while <italic>AaYABBY5</italic> downregulation resulted in a significant decrease in the concentration of artemisinin. Taken together, these results explicitly represent that AaYABBY5 is a positive regulator of artemisinin biosynthesis in <italic>A. annua</italic>.</p>