知识与财富的链接
硝酸盐转运蛋白NRT1(Nitrate transporter 1)和NRT2(Nitrate transporter 2)家族基因在高等植物氮转运过程中发挥着重要作用。为探讨NRT1和NRT2家族基因在小麦幼苗响应氮饥饿中的作用,本研究测定了氮饥饿处理过程中小麦幼苗的生长参数和叶片中叶绿素、可溶性蛋白、硝酸盐和丙二醛(MDA)的含量,并利用荧光实时定量PCR(qPCR)技术分析了叶片中NRT1(7个)和NRT2(5个)家族基因的转录水平。结果表明,氮饥饿明显抑制小麦幼苗生长,其株高、干鲜重显著下降,叶片叶绿素含量、蛋白质含量和硝酸盐含量均显著降低,而MDA含量却显著升高。在氮饥饿处理后所有测定时间点(2d、4d、6d和8d),小麦幼苗叶片中TaNRT1.1、TaNRT1.2、TaNRT1.7、TaNRT2.3和TaNRT2.4的表达均受到显著抑制;然而,氮饥饿2d时,TaNRT1.4、TaNRT1.8和TaNRT2.1的表达量显著升高;氮饥饿4d时,TaNRT1.3、TaNRT1.5和TaNRT2.5的表达量也显著升高,推测TaNRT1.3、TaNRT1.4、TaNRT1.5、TaNRT1.8、TaNRT2.1和TaNRT2.5可能在小麦幼苗响应氮饥饿中发挥着重要作用。
NRT1 and NRT2 families play important roles in the response to nitrogen starvation in higher plants. In order to explore the roles of wheat NRT1 and NRT2 genes in response to N starvation, the contents of chlorophyll, nitrates, protein and malondialdehyde (MDA) were measured in the leaves of N starved wheat seedlings. The NRT1 (7) and NRT2 (5) gene families from common wheat were identified and their transcription levels were further measured using quantitative real time PCR (qPCR) method in leaves of N starved wheat seedlings. The results indicated that nitrogen starvation significantly inhibited the growth of wheat seedlings, manifested by decreased plant heights, total fresh weights, and total dry weights. During N starvation period, contents of chlorophyll, nitrates and protein were also remarkably reduced, whereas the contents of malondialdehyde (MDA) were markedly increased in leaves of wheat seedlings. N starvation greatly inhibited the transcription levels of TaNRT1.1, TaNRT1.2, TaNRT1.7, TaNRT2.3 and TaNRT2.4 genes during all sampling time points (2 d, 4 d, 6 d, and 8 d after N starvation). However, N starvation significantly enhanced the transcript levels of TaNRT1.4, TaNRT1.8 and TaNRT2.1 genes at 2 d after N starvation, and induced the transcript levels of TaNRT1.3, TaNRT1.5 and TaNRT2.5 at 4 d after N starvation, implying that TaNRT1.3, TaNRT1.4, TaNRT1.5, TaNRT1.8, TaNRT2.1, and TaNRT2.5 might play important roles in responses of wheat seedlings to nitrogen starvation.
