Plastidic G6PDH and root structure regulation are essential for high nitrogen use efficiency in highland barley adaptation to low nitrogen
Plastidic G6PDH and root structure regulation are essential for high nitrogen use efficiency in highland barley adaptation to low nitrogen
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DOI：
10.1016/j.envexpbot.2022.105043
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发表时间：
2022-10
影响因子：
5.7
通讯作者：
J. Qin;Xiaomin Wang;Xiangxiang Wang;Mengjiao Ruan;Junjie Li;N. Gao;Xiaofan Na;Y. Bi
中科院分区：
文献类型：
--
作者：
J. Qin;Xiaomin Wang;Xiangxiang Wang;Mengjiao Ruan;Junjie Li;N. Gao;Xiaofan Na;Y. Bi
氮素利用效率（NUE）是决定作物生长和产量的主要因素。它与氮素吸收和同化效率密切相关。本研究以青稞（昆仑14）和大麦（甘啤6号）为材料，研究了它们在低氮条件下的反应及其机理。低氮胁迫下，昆仑14的根长、株高、根冠比和相对根生长速率均大于甘啤6号，表明昆仑14对低氮胁迫具有较强的耐性。低氮胁迫下甘啤6号硝酸盐和氨基酸含量下降幅度大于昆仑14号。此外，昆仑14号的硝酸盐吸收、运转和同化能力均高于甘啤6号。低氮显著诱导了昆仑14的葡萄糖-6-磷酸脱氢酶（G6 PDH）活性，尤其是质体G6 PDH（Pla-G6 PDH）活性。葡萄糖胺，G6 PDH抑制剂，降低硝酸盐吸收和同化能力在低氮胁迫下。qRT-PCR和RNA-Seq分析表明，低N显著诱导了HvG 6PDH 3基因在大麦根中的表达。此外，大麦根系中与激素、转录因子和细胞壁生物合成相关的差异表达基因在低氮胁迫下通过调控根系发育和氮代谢发挥重要作用。HvG 6PDH 3基因的过表达上调了AtNRT 1. 5和AtNRT 2. 1的表达，提高了拟南芥对硝酸盐的吸收和转运能力，从而提高了拟南芥在低氮胁迫下的种子产量。因此，HvG 6PDH 3和根构型调控基因在昆仑14耐低氮中发挥重要作用，有助于维持高氮吸收和同化效率。
Nitrogen (N) use efficiency (NUE) is a major factor determining crop growth and productivity. It is closely related to N acquisition and assimilation efficiency. In this study, the respective responses and mechanisms of highland barley (Kunlun14) and barley (Ganpi6) were investigated under low N condition. The root length, plant height, root/shoot ratio, and relative root growth rate in Kunlun14 were greater than those in Ganpi6 under low N stress, suggesting Kunlun14 has stronger tolerance to low N. The contents of nitrate and amino acids were decreased more in Ganpi6 than in Kunlun14 under low N stress. Moreover, Kunlun14 maintained higher nitrate uptake, translocation and assimilation capacity than Ganpi6. Glucose-6-phosphate dehydrogenase (G6PDH) activity, especially the plastidic G6PDH (Pla-G6PDH) activity, was markedly induced by low N in Kunlun14. Glucosamine, a G6PDH inhibitor, reduced nitrate uptake and assimilation capacity under low N stress. qRT-PCR and RNA-Seq analysis showed that the expression ofHvG6PDH3, encoding Pla-G6PDH3, was markedly induced by low N in barley roots. In addition, the differentially expressed genes in barley roots involved in hormones, transcription factors and cell wall biosynthesis play key roles under low N by regulating root development and N metabolism. Overexpression ofHvG6PDH3in Arabidopsis up-regulated the expression ofAtNRT1.5andAtNRT2.1and increased the nitrate uptake and translocation capacity, which resulted in higher seed yield inHvG6PDH3-overexpressors under low N stress. Taken together,HvG6PDH3and the genes involved in regulating root architecture play essential roles in Kunlun14 tolerance to low N, which is conductive to maintaining high N uptake and assimilation efficiency.