%0 Journal Article %T Genome Wide Transcriptomic Analysis of WRKY Gene Family Response to Biotic Stresses in Malus ×domestica %A Hanghang Zhang %A Liu Yang %A Ruli Zhou %A Yingli Zhang %A Zhengyang Wang %A Hongguang Pang %A Tuanhui Bai %A Shangwei Song %A Jian Jiao %A Miaomiao Wang %A Jiancan Feng %A Chunhui Song %A Xianbo Zheng %J American Journal of Plant Sciences %P 858-885 %@ 2158-2750 %D 2021 %I Scientific Research Publishing %R 10.4236/ajps.2021.125058 %X Apple (Malus ¡Á domestica Borkh.) is a perennial woody plant that often suffers from various biological stresses. Many harmful pathogens can infect apple trees and lead to reduced production. We comprehensively identified the WRKY genes in the apple genome and analyzed their expression in response to several biological stressors, including Alternaria alternata, Pythium ultimum, Botryosphaeria dothidea, Erwinia amylovora, Penicillium expansum, Gymnosporangium yamadae, and Apple replant disease. There were 113 MdWRKYs identified in the apple genome. Twenty-two MdWRKYs were differentially expressed in response to at least five pathogens. Promoter sequence analysis showed that these genes carried many defense- and stress-responsive elements, such as MeJA-response elements, salicylic acid-response elements, and W-box elements, in their promoters. Transient expression assays showed that MdWRKY40a and MdWRKY54h played negative roles in defense against B. dothidea infection.