Abstract：
Iron (Fe) is an essential plant nutrient that is indispensable for many physiological activities. This study is an effort to identify the molecular and biochemical basis of wheat genotypes with contrasting tolerance towards Fe deficiency. Our physiological experiments performed at the early growth stage in cv. Kanchan (KAN) showed Fe deficiency tolerance, whereas cv. PBW343 (PBW) was susceptible. Under Fe deficient condition, KAN showed delayed chlorosis, high SPAD values, and low malondialdehyde content compared to PBW, indicative of Fe deficient condition. Comparative shoot transcriptomics revealed increased expression of photosynthetic pathway genes in PBW, further suggesting its sensitivity to Fe fluctuations. Under Fe deficiency, both the cultivars showed distinct molecular re-arrangements such as high expression of genes involved in Fe uptake (including membrane transporters) and its remobilization. Specifically, in KAN these changes lead to high root phytosiderophores (PS) biosynthesis and its release, resulting in enhanced Fe translocation index. Utilizing the non-transgenic TILLING (Targeting Induced Lesions in Genomes) technology, we identified TaZIFL4.2D as a putative PS efflux transporter. Characterization of the wheat TILLING lines indicated that TaZIFL4.2 functions in PS release and Fe acquisition, thereby imparting tolerance to Fe deficiency. Altogether, this work highlights the mechanistic insight into Fe deficiency tolerance of hexaploid wheat, thus enabling breeders to select suitable genotypes to utilize nutrients for maximum yields.
摘要：
铁（Fe）是植物必需的营养素，对于许多生理活动是必不可少的。这项研究旨在鉴定小麦基因型的分子和生化基础，这些基因型对缺铁性具有相反的耐受性。我们的生理实验是在简历的早期生长阶段进行的。Kanchan(KAN)表现出缺铁耐受性，而CV。PBW343(PBW)易感。在缺铁条件下，KAN显示迟发性萎黄,高SPAD值，与PBW相比，丙二醛含量低，表明缺铁条件。比较芽转录组学显示PBW中光合途径基因的表达增加，进一步表明其对Fe波动的敏感性。在缺铁的情况下，两个品种都显示出不同的分子重排，例如与Fe摄取有关的基因的高表达（包括膜转运蛋白）及其重新动员。具体来说,在KAN中，这些变化导致较高的根铁载体（PS）生物合成及其释放，导致Fe易位指数增强。利用非转基因TILLING（靶向基因组诱导损伤）技术，我们确定TaZIFL4.2D为推定的PS外排转运蛋白。小麦TILLING品系的表征表明，TaZIFL4.2在PS释放和Fe获取中起作用，从而赋予对缺铁的耐受性。总之,这项工作强调了对六倍体小麦缺铁性的机理见解，从而使育种者能够选择合适的基因型来利用营养以获得最大产量。
