Isolation, classification and transcription profiles of the Ethylene Response Factors (ERFs) in ripening kiwifruit

• 105 ERF were newly identified from Actinidia genome database.
• ERF genes differentially expressed in response to ethylene and CA storage.
• Eight ERF were characterized as candidates for kiwifruit ripening regulation.

Ethylene is one of the most important plant hormones regulating fruit ripening. In kiwifruit, 14 AdERF genes have been reported, and some members were reported to be involved in fruit ripening and softening. However, a genome-wide investigation of the kiwifruit ERF family was not carried out. Here, 105 novel ERF genes were obtained from the kiwifruit genome. Phylogenetic and MEME analyses indicated that kiwifruit ERF genes are distributed in different subfamilies and all have single AP2/ERF domain. Moreover, some ERF members were putative repressors, as indicated by the presence of EAR motifs. The relationship between the ERF family and kiwifruit ripening we investigated with C2H4 treatment and CA storage. Gene expression analyses pointed out eight ripening related ERF genes, including four putative activators (AdERF10/14/15/75) and four putative repressors (AdERF7/8/19/21) of ripening.