摘要
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 synthetase(GS) is a key enzyme of plant nitrogen metabolism, it plays important roles in ammonia assimilation and glutamine biosynthesis. GS gene family have four members in cassava, that is cytosolic cassava4.1_008086m(Me GS1.1), cassava4.1_010581m(Me GS1.2), cassava4.1_010597m(Me GS1.3) and chloroplastic cassava4.1_008019m(Me GS2). In this study, nitrate and ammonium use efficiency(double-high) and inefficiency(double-low) genotypes subjected to low and normal nitrate and ammonium treatments, the differential enzyme activities and expression of four GS genes by use of real time RT-PCR technique were analyzed. The results showed that the activities of GS under the low nitrate nitrogen stress were lower than those under the normal nitrogen, but GS activities under the low ammonium treatment were higher than those under the normal nitrogen,while in root, neither ammonium or nitrate, GS activities under low nitrogen treatment lower than those under normal nitrogen treatmen. The expression level of chloroplastic GS was opposite to activity of GS in leaves. As a result, we inferred that there is a negative correlation between the expression of cassava chloroplastic GS gene and activity of GS, especially in leaves. The expression level of cytosolic GS gene under different low nitrogen stress,were varied differently in two types, combined with chloroplastic GS to affect the activity of GS, jointly affect the differences of nitrogen use efficiency between the double low and double high genotypes.
出处
《分子植物育种》
CAS
CSCD
北大核心
2016年第1期21-25,共5页
Molecular Plant Breeding
基金
科技部国际科技合作专项(2013DFA32020)
海南省重大科技项目子课题(ZDZX2013023-1)
中央级公益性科研院所基本科研业务费项目(ITBB2015RC01)共同资助
关键词
木薯
谷氨酰胺合成酶
氮利用率效
硝酸盐或铵盐
Cassava
Glutamine synthetase
Nitrogen use efficiency
Nitrate or ammonium
