Root extension and nitrate transporter up-regulation induced by nitrogen deficiency improves nitrogen status and plant growth at the seedling stage of winter wheat (Triticum aestivum L.)
Root extension and nitrate transporter up-regulation induced by nitrogen deficiency improves nitrogen status and plant growth at the seedling stage of winter wheat (Triticum aestivum L.)
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缺氮引起的根部伸长和硝酸盐转运蛋白上调改善了冬小麦（Triticum aestivum L.）苗期的氮状况和植物生长
DOI：
10.1016/j.envexpbot.2017.06.006
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发表时间：
2017-09-01
影响因子：
5.7
通讯作者：
Dai, Tingbo
中科院分区：
文献类型：
--
作者：
Jiang, Suyu;Sun, Jianyun;Dai, Tingbo
研究小麦幼苗生长和氮素吸收对低氮胁迫的响应，将为阐明氮高效小麦幼苗的适应机制提供信息。采用水培试验，研究了小麦品种扬麦158（耐低硝）和早扬麦（低硝敏感）在0.25 mmol L ~（-1）硝态氮（低硝营养; LN）和5 mmol L ~（-1）硝态氮（对照; CK）胁迫下根系形态和硝酸盐转运蛋白表达的变化。早扬麦的植株干重和氮含量下降幅度大于扬麦158，表明扬麦158在低硝态氮处理下具有较好的生长状况和氮素贮存能力。此外，扬麦158根系干重和吸收面积的增加幅度较大，尤其是节根。硝酸盐浓度的降低刺激了扬麦158中TaNRT1.1、TaNRT2.1和TaNRT2.2的同时上调，随后在低硝酸盐条件下上调TaNAR2.1。质膜H+-ATPase活性。(PM在扬麦158的节根中，与氮素吸收能量供应有关的TaHA 1（H+-ATPase）表达显著增加，这与TaHA 1转录本丰度的增加相一致。此外，硝酸还原酶（NR）和谷氨酰胺合成酶（GS）活性在扬麦158生长初期较高，可能是氮素吸收的反馈信号。而早扬麦的NR和GS活性在LN和CK之间无显著差异。这些结果表明，较大的根延伸和硝酸盐转运蛋白上调是扬麦158对氮素缺乏生长条件的上级适应性的主要原因。
Characterizing the responses of plant growth and nitrogen (N) uptake to low-nitrogen conditions will provide information towards elucidating the acclimation mechanism of N-efficient wheat seedlings. Two winter wheat cultivars, Yangmai158 (low-nitrate tolerant) and Zaoyangmai (low-nitrate sensitive), were supplied either 0.25 mmol L-1 nitrate (low nitrate nutrition; LN) or 5 mmol L-1 nitrate (control; CK), to investigate the responses of root morphology and nitrate transporter expression in a hydroponic experiment. Decreases in plant dry weight and N content were greater in Zaoyangmai than in Yangmai158, suggesting that Yangmai158 has a better growth status and N-storage ability in low-nitrate treatment. Additionally, root dry weight and uptake area increased to a greater extent in Yangmai158, especially in nodal roots. The decrement in nitrate concentration stimulated simultaneous upregulation of TaNRT1.1, TaNRT2.1 and TaNRT2.2 in Yangmai158, followed by upregulation of TaNAR2.1 in low-nitrate conditions. Plasma membrane H+-ATPase activity. (PM H+-ATPase), which is involved in N-uptake energy supply, increased significantly in nodal roots of Yangmai158, consistent with increasing TaHA1 transcript abundance. Furthermore, the activities of nitrate reductase (NR) and glutamine synthetase (GS) were much higher in Yangmai158 initially, which could be a feedback signal for N-uptake. However, no difference of NR and GS activity between LN and CK was found in Zaoyangmai. These results suggest that larger root extension and nitrate transporter upregulation are the major reasons for the superior acclimation of Yangmai158 to nitrogen deficient growth conditions.