甘薯β−淀粉酶家族基因的全基因组鉴定和表达分析

    Genome-wide identification and expression analysis of the β-amylase gene family in Ipomoea batatas

    • 摘要:
      目的  挖掘甘薯Ipomoea batatas基因组中β−淀粉酶(Beta-amylase)基因家族序列信息,分析结构与功能信息。
      方法  基于甘薯栽培种‘泰中6号’全基因组测序数据,利用生物信息学分析方法对鉴定到的12个甘薯β−淀粉酶家族成员进行结构域保守性分析、染色体定位、潜在重复基因筛查、保守基序分析和系统进化树构建,利用转录组数据进行低温胁迫下相关基因的表达分析。
      结果  12个β−淀粉酶基因分布于甘薯第2、4、5、6、11、12、13和14号染色体上,含有8个具有潜在重复关系的基因对。多重比对和功能结构域搜索结果显示,甘薯β−淀粉酶家族的氨基酸序列中含有3个保守性较高的区域和10个保守基序。甘薯与其他物种β−淀粉酶蛋白的系统进化分析结果显示,62个β−淀粉酶家族成员被分为S1~S7等7个亚组,甘薯β−淀粉酶家族成员主要分布在S2、S4、S5、S6以及S7亚组中,且大多与拟南芥、马铃薯以及番茄的β−淀粉酶为同一分支。转录组测序数据分析结果显示,在低温贮藏的过程中有6个甘薯β−淀粉酶基因表达量出现变化,其中‘徐薯15-1’有2个基因上调表达、4个基因下调表达,‘徐薯15-4’仅有2个基因下调表达。
      结论  β−淀粉酶是一类关键的淀粉水解酶,在甘薯生长发育和薯块贮藏阶段淀粉降解为还原糖的过程中发挥着重要作用,本研究鉴定得到的12个甘薯β−淀粉酶基因序列信息为进一步探讨甘薯β−淀粉酶基因家族的生物学功能提供数据参考。

       

      Abstract:
      Objective  To mine the sequence information of the β-amylase gene family of Ipomoea batatas genome, and analyze the structure and function of genes.
      Method  Based on the whole genome sequence data of I. batatas cultivar ‘Taizhong 6’, the bioinformatic methods were applied to analyze the identified 12 members of the β-amylase gene family and conduct the domain conservation analysis, chromosomal localization, screening of potential duplication genes, conservative motif analysis, phylogenetic tree construction. The gene expression under low temperature stress was analyzed using the transcriptomics data.
      Result  Twelve β-amylase genes were located on chromosomes No. 2, 4, 5, 6, 11, 12, 13 and 14 of I. batatas, and eight pairs showed potential duplication relationship. Multiple sequence alignment and functional domain search indicated that there were three highly conserved domains and 10 conservative motifs in the amino acid sequences of I. batatas β-amylase family. Phylogenetic trees of β-amylase proteins in I. batatas and other species showed that 62 β-amylase family members were divided into seven subgroups of S1−S7. The β-amylases of I. batatas were mainly distributed in the subgroups of S2, S4, S5, S6 and S7, most of which belonged to the same branches with Arabidopsis thaliana, Solanum tuberosum and S. lycopersicum. The results of transcriptomics data showed that six β-amylase genes expressed differentially during the low temperature storage period, of which two were up-regulated and four were down-regulated in ‘Xushu 15-1’, while only two genes were down-regulated in ‘Xushu 15-4’.
      Conclusion  The β-amylases are a key class of starch hydrolyzing enzymes that play important roles in the degradation of starch into reducing sugars during the process of I. batatas growth, development and tuber storage stages. The sequences of the identified 12 sweet potato β-amylase genes provide data reference for further study on the biological functions of I. batatas β-amylase gene family.

       

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