Genome-wide identification and functional analysis of the TIFY gene family in the response to multiple stresses in Brassica napus L.

BACKGROUND TIFY is a plant-specific protein family with a diversity of functions in plant development and responses to stress and hormones, which contains JASMONATE ZIM-domain (JAZ), TIFY, PPD and ZML subfamilies. Despite extensive studies of TIFY family in many other species, TIFY has not yet been characterized in Brassica napus. RESULTS In this study, we identified 77, 36 and 39 TIFY family genes in the genome of B. napus, B. rapa and B. oleracea, respectively. Results of the phylogenetic analysis indicated the 170 TIFY proteins from Arabidopsis, B. napus, B. rapa and B. oleracea could be divided into 11 groups: seven JAZ groups, one PPD group, one TIFY group, and two ZIM/ZML groups. The molecular evolutionary analysis showed that TIFY genes were conserved in Brassicaceae species. Gene expression profiling and qRT-PCR revealed that different groups of BnaTIFY members have distinct spatiotemporal expression patterns in normal conditions or following treatment with different abiotic/biotic stresses and hormones. The BnaJAZ subfamily genes were predominantly expressed in roots and up-regulated by NaCl, PEG, freezing, methyl jasmonate (MeJA), salicylic acid (SA) and Sclerotinia sclerotiorum in leaves, suggesting that they have a vital role in hormone signaling to regulate multiple stress tolerance in B. napus. CONCLUSIONS The extensive annotation and expression analysis of the BnaTIFY genes contributes to our understanding of the functions of these genes in multiple stress responses and phytohormone crosstalk in B. napus.