Abstract：
Riboflavin (RF) serves as a precursor to flavin mononucleotide and flavin adenine dinucleotide, which are crucial cofactors in various metabolic processes. Strict regulation of cellular flavin homeostasis is imperative, yet information regarding the factors governing this regulation remains largely elusive. In this study, we first examined the impact of external flavin treatment on the Arabidopsis transcriptome to identify novel regulators of cellular flavin levels. Our analysis revealed alterations in the expression of 49 putative transcription factors. Subsequent reverse genetic screening highlighted a member of the dehydration-responsive element binding (DREB) family, AtDREB2G, as a potential regulator of cellular flavin levels. Knockout mutants of AtDREB2G (dreb2g) exhibited reduced flavin levels and decreased expression of RF biosynthetic genes compared to wild-type plants. Conversely, conditional overexpression of AtDREB2G led to an increase in the expression of RF biosynthetic genes and elevated flavin levels. In wild-type plants, exposure to low temperatures and abscisic acid treatment stimulated enhanced flavin levels and upregulated the expression of RF biosynthetic genes, concomitant with the induction of AtDREB2G. Notably, these responses were significantly attenuated in dreb2g mutants. Our findings establish AtDREB2G is involved in the positive regulation of flavin biosynthesis in Arabidopsis, particularly under conditions of low temperature and abscisic acid treatment.
摘要：
核黄素（RF）是黄素单核苷酸和黄素腺嘌呤二核苷酸的前体，它们是各种代谢过程中的关键辅因子。严格调节细胞黄素体内平衡势在必行，然而，关于管理这一规定的因素的信息在很大程度上仍然难以捉摸。在这项研究中,我们首先研究了外部黄素处理对拟南芥转录组的影响，以确定细胞黄素水平的新调节因子。我们的分析揭示了49种推定转录因子的表达发生了变化。随后的反向遗传筛查突出了脱水反应元件结合（DREB）家族的成员，AtDREB2G,作为细胞黄素水平的潜在调节剂。与野生型植物相比，AtDREB2G（dreb2g）的敲除突变体的黄素水平降低，RF生物合成基因的表达降低。相反，AtDREB2G的条件性过表达导致RF生物合成基因的表达增加和黄素水平升高。在野生型植物中,暴露于低温和脱落酸处理刺激了黄素水平的提高，并上调了RF生物合成基因的表达，伴随着AtDREB2G的诱导。值得注意的是,这些反应在dreb2g突变体中显著减弱。我们的发现表明，AtDREB2G参与拟南芥中黄素生物合成的正向调节，特别是在低温和脱落酸处理的条件下。
