Abstract

Cystatins, as reversible inhibitors of papain-like and legumain proteases, have been identified in several plant species. Although thecystatinfamily plays crucial roles in plant development and defense responses to various stresses, this family in wheat (Triticum aestivumL.) is still poorly understood. In this study, 55 wheat cystatins (TaCystatins) were identified. AllTaCystatinswere divided into three groups and both the conserved gene structures and peptide motifs were relatively conserved within each group. Homoeolog analysis suggested that both homoeolog retention percentage and gene duplications contributed to the abundance of theTaCystatinfamily. Analysis of duplication events confirmed that segmental duplications played an important role in the duplication patterns. The results of codon usage pattern analysis showed thatTaCystatinshad evident codon usage bias, which was mainly affected by mutation pressure.TaCystatinsmay be regulated by cis-acting elements, especially abscisic acid and methyl jasmonate responsive elements. In addition, the expression of all selectedTaCystatinswas significantly changed following viral infection and cold stress, suggesting potential roles in response to biotic and abiotic challenges. Overall, our work provides new insights intoTaCystatinsduring wheat evolution and will help further research to decipher the roles ofTaCystatinsunder diverse stress conditions.Keywords:Triticum aestivum;wheat;cystatin;gene family;gene duplication;biotic and abiotic stress