Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.
Division of Plant Physiology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012, India.
Plant Physiol Biochem. 2022 May 15;179:134-143. doi: 10.1016/j.plaphy.2022.03.017. Epub 2022 Mar 17.
Wheat crop grown under elevated CO (EC) often have a lowered grain nitrogen (N) and protein concentration along with an altered grain ionome. The mechanistic understanding on the impact of CO x N interactions on the grain ionome and the expression of genes regulating grain ionome is scarce in wheat. In the present study, the interactive effect of EC and N dosage on grain yield, grain protein, grain ionome, tissue nitrate, and the expression of genes contributing to grain ionome (TaNAM-B1 and TaYSL6) are described. Three bread wheat genotypes were evaluated under two CO levels (Ambient CO (AC) of 400 ± 10 ppm and elevated CO (EC) of 700 ± 10 ppm) and two N levels (Low (LN) and Optimum N (ON). In EC, wheat genotypes HD2967 and HI 1500 recorded a significant decrease in grain nitrate content, while leaf and stem nitrate showed a significant increase. BT. Schomburgk (BTS), showed a significant increase in unassimilated nitrate and a decline in grain N and grain protein under EC. There was a general decline of grain ionome (N, P, K, Ca, Fe) in EC, except for grain Na content. The expression of genes TaNAM-B1 and TaYSL6 associated with protein and micronutrient remobilization to grains during senescence were affected by both EC and N treatments. For instance, in flag leaves of BTS, the expression of TaNAM-B1 and TaYSL6 were lower in EC-LN compared to AC-LN. In maturing spikes, transcript abundance of TaNAM-B1 and TaYSL6 were lower in EC in BTS. The altered transcript abundance of TaYSL6 and TaNAM-B1 in source and sink supports the change in grain ionome and suggests an N dependent transcriptional reprogramming in EC.
在升高的 CO（EC）环境下种植的小麦作物通常会降低籽粒氮（N）和蛋白质浓度，同时改变籽粒的离子组成。在小麦中，关于 CO x N 相互作用对籽粒离子组和调控籽粒离子组的基因表达的影响的机制理解还很缺乏。本研究描述了 EC 和 N 用量对籽粒产量、籽粒蛋白质、籽粒离子组、组织硝酸盐以及对籽粒离子组有贡献的基因（TaNAM-B1 和 TaYSL6）表达的交互作用。在两种 CO 水平（环境 CO（AC）为 400±10ppm 和升高的 CO（EC）为 700±10ppm）和两种 N 水平（低（LN）和最佳 N（ON）下，对三个面包小麦基因型进行了评估。在 EC 中，HD2967 和 HI 1500 基因型的籽粒硝酸盐含量显著降低，而叶片和茎中的硝酸盐含量显著增加。BT. Schomburgk（BTS）基因型在 EC 下表现出未同化硝酸盐的显著增加以及籽粒 N 和蛋白质的减少。除了籽粒 Na 含量外，EC 下籽粒离子组（N、P、K、Ca、Fe）普遍下降。与衰老过程中蛋白质和微量元素向籽粒再转移相关的基因 TaNAM-B1 和 TaYSL6 的表达受到 EC 和 N 处理的影响。例如，在 BTS 的旗叶中，与 AC-LN 相比，EC-LN 中的 TaNAM-B1 和 TaYSL6 表达较低。在成熟的穗中，BTS 中的 TaNAM-B1 和 TaYSL6 的转录丰度在 EC 中较低。源和汇中 TaYSL6 和 TaNAM-B1 的转录丰度的改变支持了籽粒离子组的变化，并表明 EC 中存在依赖 N 的转录重编程。
