施氮量对烤烟氮代谢关键酶基因表达及代谢产物的影响

为了探寻供氮水平对烤烟氮代谢关键基因表达与含氮化合物含量的影响,进行供氮水平及品种的两因素田间试验,分别在移栽后45、60、80 d测定鲜烟叶硝酸还原酶(NR)、谷氨酰胺合成酶(GS)、谷氨酸合成酶(GOGAT)基因表达量,以及烟叶总氮、烟碱和可溶性蛋白质的含量。结果显示,3个氮代谢关键基因的表达均受施氮量影响。栽后80 d,高氮处理(120 kg·hm^-2)的烟株可溶性蛋白含量显著(P<0.05)高于低氮处理(90 kg·hm^-2)。栽后45 d,NR基因表达量与烟碱含量呈显著(P<0.05)负相关,与可溶性蛋白含量呈极显著(P<0.01)正相关;栽后60 d,GS基因表达量与烟碱含量呈显著(P<0.05)负相关。施氮水平对烤烟氮代谢关键酶基因表达及氮代谢产物含量有显著影响,可通过调整施氮量来调控烟叶含氮化合物含量。

Effects of nitrogen application on key enzymes gene expression and yield of nitrogen metabolism in flue-cured tobacco

In order to investigate the effects of nitrogen supply levels on nitrogen metabolism, key gene expression and nitrogen compounds content in flue-cured tobacco, a two-factor field experiment of nitrogen supply level and tobacco variety was conducted. The gene expressions of nitrate reductase (NR), glutamine synthetase (GS) and glutamate synthase (GOGAT) gene, as well as total nitrogen, nicotine and soluble protein contents in flue-cured tobacco leaves were measured at 45, 60 and 80 d after planting, respectively. It was shown that the expression of these three key nitrogen metabolism genes were influenced by nitrogen supply. Eighty days after planting, soluble protein contents in tobacco with high N (120 kg·hm^-2) was significantly (P<0.05) higher than that with low N (90 kg·hm^-2). Correlation analysis showed that NR gene expression was significantly (P<0.05) negatively correlated with nicotine content, and was significantly (P<0.01) positively correlated with soluble protein content in tobacco at 45 d after planting. GS gene expression and nicotine content showed a significantly (P<0.05) negative correlation at 60 d after planting. These results suggested that the nitrogen application level had significant effect on key gene expression in nitrogen metabolism of flue-cured tobacco, and the content of nitrogenous compounds in tobacco leaves could be regulated by adjusting the application amount of nitrogen.