干旱胁迫对枳的氮含量及氮代谢相关基因表达的影响

Effects of drought stress on nitrogen content and expression of nitrogen metabolism related genes in Poncirus trifoliata(L.) Raf.

以枳为试验材料,进行干旱胁迫处理(对照组的基质相对持水量维持在55%~65%),分别在处理后第7、17、27、37天采样,研究干旱胁迫对枳侧根、主根、茎、叶片中全氮含量的影响以及氮代谢途径中NRT、NR、NiR、GS、GOGAT、GDH等16个相关基因在侧根和叶片中的表达。结果表明:随着干旱时间的延长,枳的侧根、主根、茎、叶中全氮含量与对照相比均显著下降,其中侧根全氮含量下降最为显著;枳叶片中与氮代谢相关的16个基因均能被干旱胁迫诱导而上调表达,且多数基因在干旱第27天上调至最高水平,而后随着叶片的萎蔫而下调;枳侧根中有8个基因(NRT1.2、NRT1.7、GS2、NADH–GOGAT2、NADP–GDH、GDH1、GDH2、GDH3)在干旱处理后27天呈现不同程度的上调表达,有4个基因(NRT1.1、NRT1.5、GS1、NADH–GOGAT3)的表达基本不受干旱胁迫的影响,还有4个基因(NR、NiR、Fd–GOGAT、NADH–GOGAT1)的表达显著下调。

The experiment of drought treatment of rootstock Poncirus trifoliata （L.） Raf. was carried out by using the method of drought stress and water control （the relative water holding capacity of the control group was maintained at 55% to 65%） on potted. The effects of drought stress on the total nitrogen content of the lateral roots, main roots, stems and leaves of P. trifoliata, as well as the expression of 16 genes related to NRT, NR, NiR, GS, GOGAT and GDH in the lateral roots and leaves of the nitrogen metabolism pathway were analyzed on 7 days, 17 days, 27 days and 37 days after treatment. The results showed that the total nitrogen content in the roots, main roots, stems and leaves of P. trifoliata significantly decreased with the increase of drought time, and the total nitrogen content in the lateral root decreased most significantly.16 genes of nitrogen metabolism in leaves of P. trifoliata can be up–regulated by drought stress, and most of them were increased to the highest level after drought treatment for 27 days, and then decreased with the wilting of leaves. In the lateral roots of P. trifoliata, the expression of 8 genes （NRT1.2, NRT1.7, GS2, NADH–GOGAT2, NADP–GDH, GDH1, GDH2 and GDH3） was induced by drought stress after 27 days treatment and showed up to varying degrees, and there were no significant changes in the expression of 4 genes （NRT1.1, NRT1.5, GS1, NADH–GOGAT3）, which were not affected by drought stress, and the other 4 genes （NR, NiR, Fd–GOGAT, NADH–GOGAT1） were significantly down regulated by drought stress.