Identification of the basic leucine zipper transcription factor and analysis of expression responses to biotic and abiotic stresses in kiwifruit (Actinidia Lindl.)

The basic leucine zipper (bZIP) transcription factor family is involved in regulating organ differentiation, embryogenesis, flower and vascular development, seed maturation, and plays important roles in responding to biotic and abiotic stress. To date, bZIP gene family in kiwifruit (Actinidia spp.) remains poorly understood. In this study our objective was to identify the bZIP transcription factor of kiwifruit; in this study 80 AcbZIP genes were identified in the kiwifruit genome. Based on domain architecture and phylogenetic analyses, kiwifruit bZIP genes can be classified into ten superfamilies. Synteny analysis indicated that segmental duplication events contributed to the expansion of the kiwifruit AcbZIP family. In addition, the synteny analysis between kiwifruit and Arabidopsis suggested that some of the AcbZIP genes were derived from common ancestors before the divergence of these two genera. Conserved motifs outside the AcbZIP domain may reflect their functional conservation. Furthermore, the analysis of 16 Group A AcbZIP genes showed a variety of expression patterns in five different organs and suggested some potential genes during biotic and abiotic stresses. The genome-wide identification and characterization of kiwifruit bZIP transcription factors could facilitate functional analysis of these genes and provide important information of the molecular basis of development and stress tolerance in kiwifruit.