School of BioSciences, The University of Melbourne, Parkville, VIC, 3010, Australia.
Department of Animal, Plant and Soil Sciences, School of Agriculture, Biomedicine and Environment, La Trobe University, Bundoora, VIC, 3086, Australia.
BMC Plant Biol. 2024 Sep 30;24(1):891. doi: 10.1186/s12870-024-05473-y.
Iron (Fe) deficiency affects 30-50% of the world's population. Genetic biofortification of staple crops is a promising strategy for improving human nutrition, but the number of effective precision breeding targets for Fe biofortification is small. Upstream open reading frames (uORFs) are cis-regulatory elements within the 5' leader sequence (LS) of genes that generally repress translation of the main open reading frame (mORF).
We aligned publicly available rice (Oryza sativa L.) ribo-seq datasets and transcriptomes to identify putative uORFs within important Fe homeostasis genes. A dual luciferase assay (DLA) was used to determine whether these uORFs cause repression of mORF translation and pinpoint LS regions that can be mutated for mORF derepression. A translationally repressive uORF region was identified in two positive regulators of the Fe-deficiency response: IDEF1 and IDEF2. The IDEF2-uORF peptide was highly conserved among monocots and a mutation series in the 5' LS of the wheat (Triticum aestivum L.) TaIDEF2-A1 gene demonstrated variable mORF derepression.
Together these results reveal a possible regulatory mechanism by which IDEF2 transcription factors modulate the Fe deficiency response in monocots, and highlight novel precision breeding targets to improve crop nutrition and abiotic stress tolerance.
铁（Fe）缺乏影响了世界上 30-50%的人口。对主食作物进行遗传生物强化是改善人类营养的一种有前途的策略，但用于 Fe 生物强化的有效精确育种目标数量较少。上游开放阅读框（uORF）是基因 5' 先导序列（LS）内的顺式调控元件，通常抑制主开放阅读框（mORF）的翻译。
我们对齐了公开可用的水稻（Oryza sativa L.）核糖体测序数据集和转录组，以鉴定重要铁稳态基因内的推定 uORF。双荧光素酶测定（DLA）用于确定这些 uORF 是否导致 mORF 翻译的抑制，并确定可以突变 LS 区域以解除 mORF 抑制的区域。在 Fe 缺乏反应的两个正调节剂 IDEF1 和 IDEF2 中鉴定出一个翻译抑制 uORF 区域。IDEF2-uORF 肽在单子叶植物中高度保守，小麦（Triticum aestivum L.）TaIDEF2-A1 基因 5' LS 中的突变系列证明了 mORF 解除抑制的可变程度。
这些结果共同揭示了 IDEF2 转录因子调节单子叶植物 Fe 缺乏反应的可能调控机制，并突出了新的精确育种目标，以改善作物营养和非生物胁迫耐受性。
