银杏AP2/ERF转录因子鉴定及其ERF家族在逆境胁迫下的表达分析

Identification of AP2/ERF Transcription Factors in Ginkgo biloba and the Expression of ERF Gene Family under Abiotic Stress

AP2/ERF转录因子广泛参与银杏的生物学过程,其ERF基因家族存在着通过调控次生代谢来应对环境压力的可能。为探究ERF基因家族在这一过程中的应答机制,本研究分别构建了紫外和干旱处理下银杏叶转录组数据库,利用在线生物信息学工具对银杏AP2/ERF转录因子的保守结构域、理化性质及基因家族同源性进行分析,同时利用转录组测序技术检测了ERF基因家族在这两种逆境胁迫下的表达情况,筛选其中5个与类黄酮等代谢相关的ERF基因进行荧光定量PCR验证分析。结果表明,在银杏中共鉴定到61个AP2/ERF转录因子,根据其保守结构域特点分为4类,即ERF亚家族28个、DREB亚家族23个、AP2和RAV亚家族分别为5个。不同成员之间的氨基酸数目、等电点(pI)等理化性质有较大差别。从与拟南芥、大豆的序列同源性分析结果来看,同一个亚家族的成员之间亲缘关系较近。GbERF亚家族和GbDREB亚家族同属于银杏ERF基因家族,成员数最多。转录组预测分析结果显示,大部分ERF基因家族成员在紫外和干旱胁迫诱导下的基因表达量会增加。经验证,5个基因表达量的变化情况总体与预测结果一致。本实验结果为后期开展银杏ERF基因家族的功能研究提供科学依据。

AP2/ERF transcription factors(TF) are widely involved in the biological process of Ginkgo biloba.The ERF gene family may regulate plant stress responses through mediating secondary metabolism.To understand the regulation mechanisms of ERF gene family during this process,two transcriptome databases of ginkgo leaves under UV-B and drought stress were constructed respectively.The conserved domains,physicochemical properties and gene family homology of AP2/ERF TFs were analyzed using online bioinformatics tools.The expression of ERF gene family under two adversity stresses were predicted and five ERF genes involved in flavonoid pathway were selected for RT-qPCR validation analysis.The results showed that 61 AP2/ERF TFs were identified from G.biloba,and which were classified into 28 GbERF,23 GbDREB,5 GbAP2,and 5 GbRAV,according to their conserved domains and motifs.The amino acid numbers,isoelectric point(pI) and other physicochemical properties varied greatly between different members.Sequence homology analysis with Arabidopsis thaliana and Glycine max showed that the members in the same AP2/ERF subfamily were closely related.In G.biloba,the GbERF and GbDREB subfamily together constitute the ERF gene family,transcriptome prediction analysis showed that the expression of most members of ERF gene family were increased under UV-B and drought stress.From the validation analysis,we concluded that the changes of the expression levels of these five genes were consistent with the prediction results.This study provided scientific basis for the function analysis of ERF gene family in G.biloba.