Genome-Wide Identification, Characterization, and Expression Profiling of TaDUF668 Gene Family in Triticum aestivum

DUF668s, a plant-specific gene family, encode proteins containing domain of unknown function (DUF) domains. Despite their essential functions, there is a lack of insight into Triticum aestivum TaDUF668s. Here, 31 TaDUF668s were identified from the wheat genome; according to phylogenetic relationships, they were named TaDUF668-01 to TaDUF668-31. All TaDUF668s were hydrophilic and unstable proteins. There were 22 TaDUF668s that showed subcellular localization in nucleus. Evolutionary analysis demonstrated that TaDUF668s had undergone strong purifying selection, and fragment duplication plays major role in TaDUF668 family expansion. Cis-element prediction displayed that over 90% of TaDUF668 promoter regions contain the growth and abiotic responsiveness element. Consistently, expression profiling showed that TaDUF668s were highly induced in five wheat growth and development stages, seven main different tissues, five abiotic stresses, and five pathogenic stresses. In total, 12 TaDUF668s were targeted by 20 miRNAs through the inhibition of translation and cleavage patterns. RT-qPCR results confirmed that the expression of six TaDUF668s was significantly regulated by NaCl, PEG, F. graminearum, and P. striiformis; nevertheless, the regulation patterns were different. In summary, through systematic identification, characterization, evolutionary analysis, and expression profiling, a comprehensive understanding of TaDUF668 has been obtained, which lays a foundation for further functional studies of TaDUF668.