Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, University of Copenhagen, Frederiksberg-C, Denmark.
CIBIO-InBIO, Research Centre in Biodiversity and Genetic Resources, Campus Agrário de Vairão, University of Porto, Vairão, Portugal.
J Exp Bot. 2020 Jun 22;71(12):3664-3677. doi: 10.1093/jxb/eraa115.
The F-bZIP transcription factors bZIP19 and bZIP23 are the central regulators of the zinc deficiency response in Arabidopsis, and phylogenetic analysis of F-bZIP homologs across land plants indicates that the regulatory mechanism of the zinc deficiency response may be conserved. Here, we identified the rice F-bZIP homologs and investigated their function. OsbZIP48 and OsbZIP50, but not OsbZIP49, complement the zinc deficiency-hypersensitive Arabidopsis bzip19bzip23 double mutant. Ectopic expression of OsbZIP50 in Arabidopsis significantly increases plant zinc accumulation under control zinc supply, suggesting an altered Zn sensing in OsbZIP50. In addition, we performed a phylogenetic analysis of F-bZIP homologs from representative monocot species that supports the branching of plant F-bZIPs into Group 1 and Group 2. Our results suggest that regulation of the zinc deficiency response in rice is conserved, with OsbZIP48 being a functional homolog of AtbZIP19 and AtbZIP23. A better understanding of the mechanisms behind the Zn deficiency response in rice and other important crops will contribute to develop plant-based strategies to address the problems of Zn deficiency in soils, crops, and cereal-based human diets.
F-bZIP 转录因子 bZIP19 和 bZIP23 是拟南芥缺锌响应的核心调控因子，对陆地植物 F-bZIP 同源物的系统发育分析表明，缺锌响应的调控机制可能是保守的。在这里，我们鉴定了水稻的 F-bZIP 同源物，并研究了它们的功能。OsbZIP48 和 OsbZIP50，但不是 OsbZIP49，可互补锌缺乏敏感的拟南芥 bzip19bzip23 双突变体。在正常供锌条件下，异位表达 OsbZIP50 可显著增加拟南芥的锌积累，表明 OsbZIP50 改变了 Zn 感应。此外，我们对代表单子叶植物的 F-bZIP 同源物进行了系统发育分析，支持植物 F-bZIP 分为第 1 组和第 2 组。我们的研究结果表明，水稻缺锌响应的调控是保守的，OsbZIP48 是 AtbZIP19 和 AtbZIP23 的功能同源物。深入了解水稻和其他重要作物缺锌响应的机制，将有助于开发基于植物的策略来解决土壤、作物和以谷物为基础的人类饮食中缺锌的问题。
