摘要
植物可溶性淀粉合成酶(soluble starch synthase, SS)在植物支链淀粉的合成中起着关键作用,其主要负责支链的延伸。前期我们从甘薯中克隆到IbSSI基因并对其进行了表达分析及功能验证,发现该基因在甘薯中的表达受到外源蔗糖的诱导以及昼夜节律的调控。本研究在此基础上利用染色体步移法克隆到IbSSI基因1 811 bp的启动子序列。PlantCARE在线分析表明IbSSI启动子序列富含TATA-box和CAAT-box两个基本元件,还含有与昼夜节律、光照、蔗糖、逆境响应及组织特异表达等相关的顺式作用元件。将IbSSI基因全长启动子及其6个启动子5’端缺失片段分别替换植物表达载体pBI121的CaMV 35S启动子并在本生烟草(Nicotiana benthamiana)叶片中进行瞬时表达。GUS染色结果表明不同长度片段的启动子驱动β-葡萄糖醛酸酶基因(GUS)表达的能力有所差异,其中-200 bp^-369 bp区段以及-1 015 bp^-1 304 bp区段可能存在着增强转录的重要顺式作用元件。本研究揭示了IbSSI基因受外源蔗糖诱导表达及昼夜节律调控的原因,并为进一步阐明IbSSI基因在甘薯淀粉生物合成中的作用提供了科学依据。
Soluble starch synthase I(SS) plays an important role in the amylopectin synthesis in plants, which mediates the side chain elongation. Previously we cloned IbSSI gene from sweetpotato and characterized its expression pattern and biological funtions, indicating that the expression of IbSSI was subjected to exogenous sucrose induction and circadian rhythm. In this study, the 1 811 bp promoter region of IbSSI was cloned using Genome Walking method. Online analysis by PlantCARE indicated that the sequence of IbSSI promoter was rich in TATA-box and CAAT-box, which were fundamental elements of plant promoters. Meanwhile, other cis-acting regulatory elements were also detected, which are associated with circadian rhythm, light, sucrose and stress responses and tissue-specific expression, etc. The CaMV 35 S promoter of plant expression vector pBI121 were respectively substituted by the full-length IbSSI promoter a nd its six 5’-deletion fragments, which were then transiently expressed in leaves of Nicotiana benthamiana. GUS activity staining revealed that promoter fragments of different lengths showed differential abilities in driving the expression of β-glucuronidase gene. Further analysis indicated that some important elements which could enhance the transcription levels may exist in promoter regions of-200 bp^-369 bp and-1 015 bp^-1 304 bp. This study elucidated why IbSSI was subjected to exogenous sucrose induction and circadian rhythm and provided foudation for the further interpretation of the function of IbSSI in starch synthesis in sweetpotato.
作者
王雁楠
杨育峰
杨国红
张莉
陈献功
徐心志
刘庆昌
翟红
何绍贞
Wang Yannan;Yang Yufeng;Yang Guohong;Zhang Li;Chen Xiangong;Xu Xinzhi;Liu Qingchang;Zhai Hong;He Shaozhen(Cereal Institute,Henan Academy of Agricultural Sciences,Zhengzhou,450002;Key Laboratory of Sweetpotato Biology and Biotechnology of Min istry of Agriculture and Rural Affairs,China Agricultural University,Beijing,100193)
出处
《分子植物育种》
CAS
CSCD
北大核心
2019年第20期6604-6610,共7页
Molecular Plant Breeding
基金
国家甘薯产业技术体系项目(CARS-10)
河南省科技攻关重点项目(172102110080)
河南省农业科学院科研发展专项资金项目(2018XKYH01)共同资助
