小麦谷氨酰胺合成酶基因可变剪接分析  

Alternative splicing analysis of wheat glutamine synthase genes

作　　者：韦一昊 于美琴 张晓娇[1] 王露露 张志勇[1] 马新明[1] 李会强 王小纯[1,2] WEI Yi-Hao;YU Mei-Qin;ZHANG Xiao-Jiao;WANG Lu-Lu;ZHANG Zhi-Yong;MA Xin-Ming;LI Hui-Qing;WANG Xiao-Chun(Collaborative Innovation Center of Henan Grain Crops,Henan Agricultural University,Zhengzhou 450002,Henan,China;Department of Biochemistry,College of Life Science,Henan Agricultural University,Zhengzhou 450002,Henan,China)

机构地区：[1]河南省粮食作物协同创新中心/河南农业大学,河南郑州450002 [2]河南农业大学生命科学学院,河南郑州450002

出　　处：《作物学报》2022年第1期40-47,共8页Acta Agronomica Sinica

基　　金：国家自然科学基金项目(32071956);河南省现代农业产业技术体系建设专项(S2010-01-G04)资助。

摘　　要：谷氨酰胺合成酶(glutamine synthetase,GS)是植物氮素同化的关键酶,小麦(Triticum aestivum L.)GS由12个核基因编码,即TaGS1;1-6A/6B/6D、TaGS1;2-4A/4B/4D、TaGS1;3-4A/4B/4D和TaGS2-2A/2B/2D。利用单分子测序技术获得了TaGS基因的全长转录本,发现TaGS1;1-6A有1种可变剪接转录本、TaGS1;1-6B有2种可变剪接形式;与正常转录本编码的TaGS相比,TaGS1;1-6A-1的Gln_synt_N结构域部分缺失,TaGS1;1-6B-3缺少Gln_synth_gly_rich_site结构域;TaGS1;1-6B-4是新鉴定的转录本,编码缺少Gln_synth_gly_rich_site和Gln_synth_cat_dom结构域的GS蛋白。进一步研究了氮肥对不同氮效率小麦品种可变剪接转录本表达的影响,发现氮高效品种YM49叶片TaGS1;1-6A-1表达水平显著高于氮低效品种XN509,且随着氮肥增加而升高;YM49根系TaGS1;1-6A-1表达随供氮量增加而升高,XN509却呈现相反趋势。TaGS1;1-6B-3在YM49和XN509中有相似的表达趋势,高浓度NO3-促进TaGS1;1-6B-3在叶片中表达,却抑制其在根中的表达;高浓度NH4+抑制TaGS1;1-6B-3在叶片中表达,但在根中表达影响较小。TaGS1;1-6B-4主要在低氮条件下表达,NH4+浓度不影响其在YM49根中的表达。了解TaGS基因可变剪接有助于阐明TaGS同工酶在小麦氮代谢中的功能。As a key enzyme for nitrogen assimilation in plant,glutamine synthetase(TaGS)is encoded by 12 genes in common wheat(Triticum aestivum L.),namely TaGS1;1-6A/6B/6D,TaGS1;2-4A/4B/4D,TaGS1;3-4A/4B/4D,and TaGS2-2A/2B/2D.Tran-scripts of TaGS genes were obtained using the single molecular sequencing technology,and the results showed that TaGS1;1-6A had one alternative splicing(AS)version of transcripts and TaGS1;1-6B had two AS versions.Compared with the TaGS encoded by normal transcript,TaGS1;1-6A-1 lacked part of the Gln_synt_N domain,and TaGS1;1-6B-3 lacked the Gln_synth_gly_rich_site domain;TaGS1;1-6B-4 was a new AS event,and encoded a truncated GS without Gln_synth_gly_rich_site and Gln_synth_cat_dom domain.The relative expression level of TaGS alternative splicing transcripts of wheat cultivars with different nitrogen use efficiencies showed that the relative expression level of TaGS1;1-6A-1 in leaves of YM49(N-efficient)was significantly higher than that of XN509(N-inefficient),and increased with the increase of nitrogen supply.In roots,the relative expression of TaGS1;1-6A-1 increased with the increase of nitrogen supply in YM49,but decreased in XN509.TaGS1;1-6B-3 showed a similar expression trend in YM49 and XN509,and high concentration of NO3-promoted the expression of TaGS1;1-6B-3 in leaves while inhibited in roots.High concentration of NH4+inhibited the expression of TaGS1;1-6B-3 in leaves,but had little effect in roots.TaGS1;1-6B-4 was mainly expressed under low nitrogen condition,and its expression in roots of YM49 was not affected by NH4+supply.Understanding the AS transcript versions of TaGS genes is helpful to illustrate the functions of TaGS isozymes in nitrogen metabolism of wheat.

关 键 词：小麦 谷氨酰胺合成酶 转录 可变剪接 

分 类 号：S512.1[农业科学—作物学]