Genome-wide Analysis of WRKY Transcription Factors in Solanum tuberosum

The WRKY transcription factor family is widely involved in regulating plant development and defense response against various biotic and abiotic stresses.The Hidden Markov Model Profile(HMM) of WRKY domain was used to identify WRKY transcription factors in potato genome with HMMER 3.0.All together 81 potato WRKY transcription factors were identified and then classified into three main groups,with 5 subgroups in Group Ⅱ,namely Ⅱ-a,Ⅱ-b,Ⅱ-c,Ⅱ-d,and Ⅱ-e.The constructed phylogenetic tree of WRKY genes among potato,Arabidopsis and rice demonstrated that the distinct gene expansion events occurred in the genome of potato and rice,respectively,while the gene expansion of Group Ⅱ-e was unique in potato genome.The potato WRKY transcription factors showed similar motif compositions within each group,but different ones among different groups,though several conserved motifs were shared by all.Furthermore,28 potato WRKY genes showed distinct expression patterns in response to stresses of wounding,drought,salt,and virus invasion.The expressions of several potato WRKY genes were significantly up/down-regulated,implying that these members might participate in regulating the defense response against various biotic and abiotic stresses.