Identification of ERF genes in peanuts and functional analysis of AhERF008 and AhERF019 in abiotic stress response

Ethylene-responsive factor (ERF) play an important role in regulating gene expression in plant development and response to stresses. In peanuts (Arachis hypogaea L.), which produce flowers aerially and pods underground, only a few ERF genes have been identified so far. This study identifies 63 ERF unigenes from 247,313 peanut EST sequences available in the NCBI database. The phylogeny, gene structures, and putative conserved motifs in the peanut ERF proteins were analysed. Comparative analysis revealed the absence of two subgroups (A1 and A3) of the ERF family in peanuts; only 10 subgroups were identified in peanuts compared to 12 subgroups in Arabidopsis and soybeans. AP2/ERF domains were found to be conserved among peanuts, Arabidopsis, and soybeans. Outside the AP2/ERF domain, many soybean-specific conserved motifs were also detected in peanuts. The expression analysis of ERF family genes representing each clade revealed differential expression patterns in response to biotic and abiotic stresses. Overexpression of AhERF008 influenced the root gravity of Arabidopsis, whereas overexpression of AhERF019 enhanced tolerance to drought, heat, and salt stresses in Arabidopsis. The information generated in this study will be helpful to further investigate the function of ERFs in plant development and stress response.     

雷公藤AP2/ERF转录因子基因的克隆与分析

该研究以雷公藤发状根为材料,根据雷公藤根转录组数据设计引物,采用RT-PCR方法克隆得到2个雷公藤AP2/ERF转录因子,分别命名为TwAP2/ERF1基因(GenBank登录号:GAVZ01042389.1)和TwAP2/ERF2基因(GenBank登录号:GAVZ01016765.1)。TwAP2/ERF1基因含有一个525bp开放阅读框(ORF),编码186个氨基酸;TwAP2/ERF2基因的ORF为789bp,编码262个氨基酸;2个基因编码的蛋白质均为亲水性蛋白质。系统进化分析表明,TwAP2/ERF1与油桐(Vernicia fordii)AP2/ERF(APQ47444.1)和木油桐(Vernicia montana)AP2/ERF(APQ47365.1)相似性较高,TwAP2/ERF2与毛果杨(Populus trichocarpa)AP2/ERF(XP_002304640.1)和樱桃(Prunus pseudocerasus)AP2/ERF(ALD84477.1)相似性较高。雷公藤发状根经MeJA诱导后,TwAP2/ERF1基因的相对表达量明显提高,并于处理后9h达到最高值,为对照表达量的16.77倍;而MeJA处理对TwAP2/ERF2基因的表达表现出抑制作用,但于处理后48h相对表达量有所提高。研究表明,雷公藤TwAP2/ERF1转录因子响应MeJA早期诱导正调控,推测其可能参与调控雷公藤植物次生代谢产物的生物合成,该研究结果为阐明雷公藤次生代谢物质的生物合成调控与利用现代生物技术提高雷公藤植物细胞中次生代谢物质的含量奠定了基础。     

Identification of the mulberry genes involved in ethylene biosynthesis and signaling pathways and the expression of MaERF-B2-1 and MaERF-B2-2 in the response to flooding stress

The phytohormone ethylene is essential to plant growth and development. It plays crucial roles in responses to biotic and abiotic stress. The mulberry tree is an important crop plant in countries in which people rear silkworms for silk production. The availability of the mulberry genome has made it possible to identify mulberry genes involved in ethylene biosynthesis and signal pathways. A total of 145 mulberry genes were identified by both homology-based and hidden Markov model (HMM) search, including 29 genes associated with ethylene biosynthesis and 116 genes in the AP2/ERF family. Studies on gene structure have provided a genetic basis for understanding the functions of these genes. The differences in gene expression were also observed in different tissues. The expression of two mulberry genes in the AP2/ERF family, MaERF-B2-1 and MaERF-B2-2, was found to be associated with the response to flooding stress.