甜瓜谷氨酰胺合成酶基因在不同氮素条件下的表达分析

Expression Analysis of Glutamine Synthetase Gene under Different Nitrogen Sources in Melon (Cucmis Melo L.)

采用半定量RT-PCR对甜瓜质体型谷氨酰胺合成酶(GS2)基因进行mRNA的表达检测,观察不同氮源以及氮源不同配比对GS2基因表达的影响,并以actin为内参照进行基因表达水平的半定量分析。结果显示,在硝态氮处理下,随着氮浓度的增加,GS2基因的表达量增高,但是随着处理时间的延长而降低。在铵态氮处理下,处理初期GS2基因的表达水平随着氮浓度的增大而降低,而后随着氮浓度的增加而升高。研究表明,GS2基因的表达水平随着氮素浓度的提高而升高,升高的比例因氮源形态以及处理时间有所不同。不同氮形态比例的氮源处理对GS2基因表达的影响无明显的规律。

The effects of different nitrogen forms （NO3ˉ-N and NH4^＋ -N）, and of different ratio combinations of the two, on the expression of Chloroplastic glutamine synthetase gene （GS2） in melon （Cucum/s melo L.） were studied by the method of RT-PCR. The results showed that, when NO3ˉ-N was used as the sole nitrogen source, the expression of GS2 gene increased with the increase of nitrogen concentration, but decreased with the increase of treatment time. However, when NH4^＋ -N was used as the sole nitrogen source, the expression of GS2 gene declined at the beginning, and soon increased rapidly with the increase of treatment time and nitrogen concentration. Therefore, the study indicated that, the expression of GS2 .gene was generally enhanced by the increase of culture nitrogen concentration, regardless of nitrogen forms used; the increasing amount of expression was different according to the nitrogen sources or the treatment time. The different ratio combinations of the two nitrogen forms had no obvious influence on the expression behaviour of GS2 gene.