Glutamine application promotes nitrogen and biomass accumulation in the shoot of seedlings of the maize hybrid ZD958
Glutamine application promotes nitrogen and biomass accumulation in the shoot of seedlings of the maize hybrid ZD958
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DOI：
10.1007/s00425-020-03363-9
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发表时间：
2020-02-17
期刊：
影响因子：
4.3
通讯作者：
Li, Xuexian
中科院分区：
文献类型：
--
作者：
Ul Hassan, Mahmood;Islam, Md Monirul;Li, Xuexian
主要结论谷氨酰胺（Gln）是一种有效的氮源，可以促进ZD 958（一个具有巨大遗传改良潜力的优良玉米杂交种）幼苗在较小但足够的根系条件下地上部氮和生物量的积累。氨基酸是土壤氮素资源的重要组成部分。然而，氨基酸-N如何影响作物生长仍有待进一步研究。在此，谷氨酰胺（Gln）的应用（80%NH4NO3 + 20%Gln;混合N）促进玉米杂交种ZD 958的地上部生长。混合氮处理下，地上部的N浓度增加，这与地上部的SPAD值、GS/GOGAT活性、谷氨酸、天冬酰胺、游离氨基酸和可溶性蛋白质的积累增加有关。另一方面，根生长减少时，暴露于谷氨酰胺的干重显着降低，根冠比，和初级，种子，冠，总根长，以及不利的生理变化。在根中ZmAMT1.3、ZmNRT2.1和ZmAAP 2的表达上调以及在地上部中ZmAMT1.1、ZmAMT1.3和ZmLHT 1的表达上调预处理了地上部中的N过量积累并促进了地上部的生长，这可能是通过增强N向地上部的转运来实现的。总之，谷氨酰胺是一个有效的N源，促进地上N和生物量积累的ZD 958幼苗时，调节一个较小的，但足够的根系。值得注意的是，ZD 958的亲本系Z58和昌7 -2在Gln反应方面表现出广泛的变异，这可能部分归因于本研究中揭示的顺式元件和编码区的单核苷酸多态性（SNP）以及Z58和昌7 -2之间大量的未鉴定的遗传变异。这两个优良自交系的广泛的遗传分化意味着ZD 958在有机氮利用效率方面具有进一步遗传改良的潜力。
Main conclusion Glutamine (Gln) is an efficient nitrogen source in promoting aboveground nitrogen and biomass accumulation in ZD958 (an elite maize hybrid with great potential for further genetic improvement) seedlings when conditioning a smaller but adequate root system. Amino acids account for a significant part of nitrogen (N) resources in the soil. However, how amino acid-N affects crop growth remains to be further investigated. Here, glutamine (Gln) application (80% NH4NO3 + 20% Gln; mixed N) enhanced shoot growth of the maize hybrid ZD958. N concentration in the shoot increased, which is associated with favorable increases in SPAD values, GS/GOGAT activities, and accumulation of glutamate, asparagine, total free amino acids and soluble proteins in the shoot under mixed N. On the other hand, root growth was reduced when exposed to Gln as indicated by the significantly lower dry weight, root/shoot ratio, and primary, seminal, crown, and total root lengths, as well as unfavorable physiological alterations. Up-regulation of expression of ZmAMT1.3, ZmNRT2.1, and ZmAAP2 in the root and that of ZmAMT1.1, ZmAMT1.3, and ZmLHT1 in the shoot preconditioned N over-accumulation in the shoot and facilitated shoot growth, presumably via enhancing N translocation to the shoot, when Gln was supplied. Together, Gln is an efficient N source in promoting aboveground N and biomass accumulation in ZD958 seedlings when conditioning a smaller but adequate root system. Notably, ZD958 ' s parental lines Z58 and Chang7-2 displayed a wide range of variations in Gln responses, which may be partially attributed to single nucleotide polymorphisms (SNPs) in cis-elements and coding regions revealed in this study and much larger quantities of unidentified genetic variations between Z58 and Chang7-2. Extensive genetic divergence of these two elite inbred lines implied large potentials for further genetic improvement of ZD958 in relation to organic N use efficiency.