烟草β-微管蛋白基因NtTubB的克隆及逆境响应分析

Cloning and Abiotic Stress Response Analysis of β-Tubulin Gene NtTubB in Nicotiana tabacum

为明确烟草NtTubB在烟草中的生物学功能,在烟草K326中同源克隆到1个TubB蛋白基因NtTubB,并对其基因结构、生物信息学预测、进化关系以及逆境下的表达模式进行分析。结果表明,NtTubB基因cDNA全长为2 783 bp,其中开放阅读框2 475 bp,由3个外显子和2个内含子组成,编码443个氨基酸残基组成的亲水蛋白。NtTubB蛋白序列无信号肽和跨膜结构域,存在多个磷酸化位点,主要定位于细胞质中,序列高度保守,尤其是N端序列,含有2个保守结构域(GTPase domain和C-terminal domain),均属于Tubulin/FtsZ family家族。高级结构以α-螺旋和无规卷曲为主。进化分析表明,普通烟草NtTubB的氨基酸序列与林烟草NsTubB高度同源。逆境响应分析表明,NtTubB基因受脱落酸(ABA)、水杨酸(SA)、赤霉素(GA)、茉莉酸甲酯(MeJA)、过氧化氢(H2O2)、高盐、低温和高温诱导,暗示烟草NtTubB基因参与了多种激素和非生物胁迫的应答反应。

To identify the biological function of NtTubB in tobacco, TubB protein gene NtTubB was homologously cloned in tobacco K326. The gene structure, bioinformatics prediction, evolutionary relationship and expression pattern under abiotic stress of NtTubB were analyzed. The results showed that the cDNA sequence of NtTubB was2 783 bp in full length with an open reading frame(ORF) of 2 475 bp(contained three exons and two introns), encoding a hydrophilic protein consisting of 443 amino acids residues. NtTubB protein sequence had no signal peptide and transmembrane domain, and contained multiple phosphorylation sites, mainly located in cytoplasm. The protein sequence was highly conserved, especially the N-terminal sequence, and it contained two conserved domains(GTPase domain and C-terminal domain), which belonged to the Tubulin/FtsZ family. In addition, the advanced structure was mainly based on alpha helix and random coil. Evolutionary analysis showed that the amino acid sequence of NtTubB in common tobacco and Ns TubB in Nicotiana sylvestris were highly similar. Abiotic stress response analysis showed that NtTubB gene was induced by ABA, SA, GA, MeJA, H2 O2, high salinity,low temperature and high temperature, which indicated that NtTubB might be involved in response to various hormones and abiotic stresses.