The Artemisia annua FLOWERING LOCUS T Homolog 2, AaFT2, is a key regulator of flowering time

Abstract

Artemisia annua is a typical short-day photoperiod (SD) and belongs to Asteraceae family. FLOWERING LOCUS T Homolog genes play important roles in regulation of flowering time. Two FT-like genes AaFT1 and AaFT2 were isolated from cDNA libraries constructed from leaves of A. annua. The gene expression analysis revealed that AaFT1 and AaFT2 mRNAs were expressed predominantly in leaves and could be induced by GA3. Subcellular localization results indicated that AaFT1 and AaFT2 proteins were both localized to the nuclei and cytoplasm. The Y2H assay results indicated that AaFT1 and AaFT2 could interact with a bZIP transcription factor, AaFD. AaFT2 was induced by SDs condition and may play an important role in modulation of flowering. In the present study, we performed RNA interference (RNAi) experiments to inhibit the mRNA level of AaFT2 in A. annua for detecting AaFT2 gene function. Our findings suggest that inhibition of AaFT2 may delay the flowering time and increase the accumulation of artemisinin (ART) in transgenic A. annua. Collectively, these results indicate that AaFT2 is a key regulator of regulation flowering time and can be used for genetic engineering to improve artemisinin yield.