title: Evolutionary and Expression Analyses of the Apple Basic Leucine Zipper Transcription Factor Family.
abstract: Transcription factors (TFs) play essential roles in the regulatory networks controlling many developmental processes in plants. Members of the basic leucine (Leu) zipper (bZIP) TF family, which is unique to eukaryotes, are involved in regulating diverse processes, including flower and vascular development, seed maturation, stress signaling, and defense responses to pathogens. The bZIP proteins have a characteristic bZIP domain composed of a DNA-binding basic region and a Leu zipper dimerization region. In this study, we identified 112 apple (Malus domestica Borkh) bZIP TF-encoding genes, termed MdbZIP genes. Synteny analysis indicated that segmental and tandem duplication events, as well as whole genome duplication, have contributed to the expansion of the apple bZIP family. The family could be divided into 11 groups based on structural features of the encoded proteins, as well as on the phylogenetic relationship of the apple bZIP proteins to those of the model plant Arabidopsis thaliana (AtbZIP genes). Synteny analysis revealed that several paired MdbZIP genes and AtbZIP gene homologs were located in syntenic genomic regions. Furthermore, expression analyses of group A MdbZIP genes showed distinct expression levels in 10 different organs. Moreover, changes in these expression profiles in response to abiotic stress conditions and various hormone treatments identified MdbZIP genes that were responsive to high salinity and drought, as well as to different phytohormones.
authors.affiliation: State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F UniversityYangling, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F UniversityYangling, China.
authors.forename: Jiao
authors.initials: J
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F University Yangling, China.
authors.forename: Rongrong
authors.initials: R
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F UniversityYangling, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F UniversityYangling, China.
authors.forename: Chunlei
authors.initials: C
authors.lastname: Guo
authors.affiliation: College of Horticulture, Qingdao Agricultural University Qingdao, China.
authors.forename: Hongmin
authors.initials: H
authors.lastname: Hou
authors.affiliation: State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F UniversityYangling, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F UniversityYangling, China.
authors.forename: Xiping
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F UniversityYangling, China; Key Laboratory of Horticultural Plant Biology and Germplasm Innovation in Northwest China, Ministry of Agriculture, Northwest A&F UniversityYangling, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Gao
keywords: apple (Malus domestica); bZIP genes; gene expression; phylogenetic analysis; synteny analysis