• ISSN 1008-505X
  • CN 11-3996/S
周健飞, 武云杰, 薛刚, 徐世晓, 彭玉富, 杨铁钊. 烟叶成熟期氮代谢酶活性、基因表达与烤烟氮素利用效率的关系[J]. 植物营养与肥料学报, 2018, 24(3): 625-632. DOI: 10.11674/zwyf.17286
引用本文: 周健飞, 武云杰, 薛刚, 徐世晓, 彭玉富, 杨铁钊. 烟叶成熟期氮代谢酶活性、基因表达与烤烟氮素利用效率的关系[J]. 植物营养与肥料学报, 2018, 24(3): 625-632. DOI: 10.11674/zwyf.17286
ZHOU Jian-fei, WU Yun-jie, XUE Gang, XU Shi-xiao, PENG Yu-fu, YANG Tie-zhao. Relationship between nitrogen metabolic enzyme activity, gene expression and nitrogen use efficiency of flue-cured tobacco in maturing stage[J]. Journal of Plant Nutrition and Fertilizers, 2018, 24(3): 625-632. DOI: 10.11674/zwyf.17286
Citation: ZHOU Jian-fei, WU Yun-jie, XUE Gang, XU Shi-xiao, PENG Yu-fu, YANG Tie-zhao. Relationship between nitrogen metabolic enzyme activity, gene expression and nitrogen use efficiency of flue-cured tobacco in maturing stage[J]. Journal of Plant Nutrition and Fertilizers, 2018, 24(3): 625-632. DOI: 10.11674/zwyf.17286

烟叶成熟期氮代谢酶活性、基因表达与烤烟氮素利用效率的关系

Relationship between nitrogen metabolic enzyme activity, gene expression and nitrogen use efficiency of flue-cured tobacco in maturing stage

  • 摘要:
    目的 谷氨酰胺合成酶 (NtGS1NtGS2) 和硝酸还原酶 (NtNit) 基因的表达丰度反映了作物氮素代谢的特征。研究不同氮效率烤烟品种成熟期叶片的氮代谢相关酶活性和相关基因的表达,加深理解不同烤烟品种叶片氮素代谢的生理生化机制,为耐氮肥品种选育提供理论基础。
    方法 以氮效率不同的三个烤烟品种豫烟10号、K326和NC89为材料进行盆栽试验。在叶龄35、45、55、65、75 d (以幼叶长1 cm、宽0.5 cm时作为叶龄第1天) 取第12片叶 (自下向上数),采用实时荧光定量PCR技术,测定叶片谷氨酰胺合成酶基因 (NtGS1NtGS2) 和硝酸还原酶基因 (NtNit) 的表达丰度,同时采用常规生理生化测试技术对叶片酶活性和NH4+ 浓度、总氮、可溶性蛋白、质外体相关指标以及氨气挥发量进行测定。
    结果 各品种NtGS1表达丰度自叶龄35 d始大幅上调,于55 d达到最大值后表达下调。NtGS2表达丰度自35 d始呈持续下调表达。NtNit表达整体变化趋势与NtGS2相似。在叶龄45~65 d,上述三种基因的表达丰度均表现为NC89 > K326 > 豫烟10号,且品种间表达差异达极显著水平。NtGS1基因表达丰度与叶片总氮、叶片铵浓度、质外体铵浓度以及氨气挥发量呈极显著负相关,与NR活性和质外体pH呈显著负相关。NtGS2基因表达丰度与GS活性、总氮、可溶性蛋白含量和质外体pH呈极显著正相关,与NR活性、叶片铵浓度呈显著正相关,而与质外体铵浓度和氨气挥发量呈显著负相关。NR基因表达丰度与总氮、可溶性蛋白含量、叶片铵浓度呈显著正相关,与氨气挥发量呈显著负相关。
    结论 氮低效烤烟品种成熟期叶片中两种谷氨酰胺合成酶同工酶活性均较低,氮素转移和再利用能力差,导致植株吸收的氮素以氨气形式挥发损失量大,叶片衰老速度较快。而氮高效品种氮素同化和再利用能力较强,氨气挥发量小,易发生贪青晚熟。

     

    Abstract:
    Objectives Enzyme activities and gene expression represent the nitrogen metabolism of crops. Studying these gene expression and enzyme activities in leaves of mature tobacco cultivars will help to elucidate physiological and biochemical differences between caltivars, provide theoretical basis for breeding of nitrogen inefficient varieties.
    Methods Three flue-cured tobacco varieties Yuyan 10, K326 and NC89 with different nitrogen efficiencies were used as tested materials, the abundance of glutamine synthetase and nitrate reductase gene in mature leaves was measured using the Real-time PCR, the leaf enzyme activities, NH4+ concentration, total nitrogen, soluble protein, apoplast related indicators and ammonia volatilization were determined using the physiological and biochemical test techniques.
    Results The NtGS1 gene expression abundance of all cultivars was significantly increased from 35 d, reaching the maximum at 55 d, and then down-regulated. The gene expression abundance of NtGS2 was continuously down regulated since 35 d. The overall trend of NtNit gene expression was similar to that of NtGS2. At the age of 45–65 d, the expression abundance of the above three genes all showed NC89 > K326 > Yuyan 10, and the differences among the cultivars reached the extremely significant level. The abundance of NtGS1 gene was significantly and negatively correlated with total nitrogen, leaf ammonium concentration, extracellular ammonium concentration and ammonia volatilization, and negatively correlated with the NR activity and apoplast pH. Very significant positive correlations were observed between the NtGS2 gene abundance and GS activity, total nitrogen, soluble protein content and apoplast pH, and it was significantly and positively correlated with the NR activity and leaf ammonium concentration. However, it had significant negative correlations with ammonium concentration and ammonia volatilization. The NR gene expression abundance was positively correlated with the total nitrogen, soluble protein content and leaf ammonium concentration, but negatively correlated with the ammonia volatilization.
    Conclusions Nitrogen-inefficient flue-cured tobacco cultivars are weak in nitrogen transferring and reutilization, nitrogen would volatilize mainly in the form of ammonia, leading to faster leaf senescence. However, nitrogen-efficient cultivars are strong in nitrogen reutilization, nitrogen is thus less volatilized in ammonia, the aging is postponed as a result.

     

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