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谷氨酰胺合成酶(GS)是植物氮代谢中的关键酶,在氨同化和谷氨酰胺生物合成中起着重要的作用。木薯中谷氨酰胺合成酶基因家族有四个基因,分别是细胞质型cassava4.1_008086m(Me GS1.1),cassava4.1_010581m(Me GS1.2),cassava4.1_010597m(Me GS1.3)和叶绿体型cassava4.1_008019m(Me GS2)。实验采用q RT-PCR技术分析铵盐和硝酸盐两种不同的氮源低氮胁迫下耐低氮品种(双高CH16)和低氮敏感型品种(双低G16)GS基因的表达差异。结果表明,在低铵盐氮源处理下木薯两类品种的GS酶活在叶中要高于正常氮源处理,根中低于正常氮源处理,而低硝酸盐氮源处理下木薯两类品种的GS酶活在叶和根中要低于正常氮源。在不同低氮源处理下,两类材料叶绿体型GS表达量在叶中始终与GS酶活存在相反现象。因此,推测木薯叶片中叶绿体型GS表达量可能与GS酶活呈负相关关系。而细胞质型GS表达量差异较大,与叶绿体型GS共同影响GS酶活,影响着木薯的氮利用效率。
Glutamine synthase (GS) is a key enzyme in plant nitrogen metabolism and plays an important role in ammonia assimilation and glutamine biosynthesis. There are four genes in the cassava glutamine synthetase gene family, which are cytoplasmic cassava4.1_008086m (Me GS1.1), cassava4.1_010581m (Me GS1.2), cassava4.1_010597m (Me GS1.3) and chloroplast cassava4 .1_008019m (Me GS2). Q RT-PCR was used to analyze the differences in the expression of GS genes between low nitrogen-sensitive varieties (double high CH16) and low-nitrogen sensitive varieties (double low G16) under low nitrogen stress. The results showed that under the treatment of low ammonium salt source, the GS activity of two varieties was higher than that of normal nitrogen source, lower than that of normal nitrogen source, and low nitrogen source of nitrogenase The variety of GS activity in the leaves and roots to be lower than the normal nitrogen source. Under different treatments of low nitrogen source, the chloroplast-type GS expression levels of the two types of materials always had the opposite phenomenon with the GS activity in the leaves. Therefore, it is speculated that the chloroplast GS expression in cassava leaves may be negatively correlated with GS activity. However, the expression of cytoplasmic GS varied greatly, and GS together with chloroplast GS affected the enzyme activity, affecting the nitrogen utilization efficiency of cassava.