The phytochrome-interacting factor DcPIF3 of carrot plays a positive role in drought stress by increasing endogenous ABA level in Arabidopsis

The phytochrome-interacting factor (PIF) subfamily of basic helix-loop-helix (bHLH) transcription factors plays a critical role in plant growth and development. However, there has been no detailed report on the PIFs in carrot. In this study, we present the identification and characterization of DcPIF gene family in carrot (Daucus carota L.). Phylogenetic analysis indicated that PIFs from carrot and other five plant species could be divided into four groups supported by similar gene structure and motif analysis. Expression profiles showed that all DcPIF genes were tissue-specific and could be induced by drought or abscisic acid (ABA) treatment except DcPIF7.1, among which DcPIF3 was the most responsive. The DcPIF3-overexpressed Arabidopsis plants exhibited more tolerance to drought stress, with higher antioxidant capacity and lower malondialdehyde content after drought treatment than wild type plants. Further stress tolerance assays revealed that DcPIF3 plays a positive role in drought stress by increasing endogenous ABA level and promoting the expression of ABA-related genes. Our results can enrich the understanding of DcPIF family genes and lay a foundation for further investigation of DcPIF3 function to defend against drought stress in carrot.