摘要
腺苷二磷酸葡萄糖焦磷酸化酶(ADP-glucose pyrophosphorylase,AGPase)是作物淀粉合成的关键酶,由两个小亚基(small subunit,AGPS)和两个大亚基(large subunit,AGPL)组成,具有细胞质(cytosol)和质体(plastid)两种亚型。AGPL1是胞质型大亚基,对该酶活性的发挥具有重要功能。已有研究表明,过表达小麦胞质AGPase大亚基TaAGPL1-1D基因显著提高了小麦AGPase活性和淀粉积累速率,说明TaAGPL1-1D在淀粉生物合成中起着重要作用。将TaAGPL1-1D启动子与小麦籽粒cDNA文库进行酵母单杂交,筛选出一个转录因子TabHLH39,随后对TabHLH39与TaAGPL1-1D启动子之间的互作进行了验证;采用大麦条纹花叶病毒诱导的基因沉默技术,在田间小麦植株基因组内沉默了该转录因子,发现BSMV-VIGS-TabHLH39病毒沉默小麦植株籽粒的粒长、粒宽、粒重和淀粉含量均显著下降,且TaAGPL1-1D的表达水平也显著降低,表明TabHLH39可能通过正向调控TaAGPL1-1D基因的表达,参与了小麦淀粉的合成。
The heterotetrameric ADP-glucose pyrophosphorylase(AGPase)is the key enzyme in plant starch synthesis,and it is composed of two large subunits(AGPL)and two small subunits(AGPS),consisting of cytosolic and plastidial subunits.AGPL1 belongs to cytosolic subunit and has important influence on the function of AGPase.Previous study showed that overexpression of the TaAGPL1-1D gene,encoding wheat cytosolic large subunit of AGPase,significantly increased the activity of wheat AGPase and the rate of starch accumulation,suggesting that TaAGPL1-1D played an important role in starch biosynthesis.The expression of functional genes is often controlled by transcription factors,so in order to further explore the molecular mechanism of starch synthesis in bread wheat,this study isolated a transcription factor-TabHLH39,one family of the basic/helix-loop-helix family by using yeast one-hybrid(Y1 H)between TaAGPL1-1D and cDNA library of wheat grains.The binding capacity between TabHLH39 and the TaAGPL1-1 D promoter was further verified by using Y1 H analysis.Then,the barley stripe mosaic virus-virus induced gene-silencing(BSMV-VIGS)method was used to determine its function in regulating the starch synthesis in field,and found that the grain length,width,and weight of BSMV-VIGS-TabHLH39-infected wheat plant grains were significantly inhibited and its starch contents were also significantly decreased by 8.8%compared to BSMV-VIGS-GFP wheat grains.Additionally,the transcription levels of the TaAGPL1-1D and BSMV-VIGS-TabHLH39 genes were decreased markedly.These results suggested that TabHLH39 could be a positive regulator of the TaAGPL1-1D gene,and could be involved in starch synthesis in bread wheat.
作者
董洁
李鸽子
韩巧霞
谢迎新
王永华
冯伟
马冬云
王晨阳
郭天财
康国章
DONG Jie;LI Gezi;HAN Qiaoxia;XIE Yingxin;WANG Yonghua;FENG Wei;MA Dongyun;WANG Chenyang;GUO Tiancai;KANG Guozhang(National Engineering Research Center for Wheat,Agronomy Institute,Henan Agricultural University,Zhengzhou 450046,China)
出处
《中国农业科技导报》
CAS
CSCD
北大核心
2020年第10期18-26,共9页
Journal of Agricultural Science and Technology
基金
国家自然科学基金项目(31871550,U1704110和31571575)
国家转基因生物新品种培育科技重大专项(2016ZX08002003)
河南省重点研发与推广专项(182102110102)。