The Cysteine-Rich Repeat Protein TaCRR1 Participates in Defense against Both Rhizoctonia cerealis and Bipolaris sorokiniana in Wheat.

The domain of unknown function 26 (DUF26), harboring a conserved cysteine-rich motif (C-X8-C-X2-C), is unique to land plants. Several cysteine-rich repeat proteins (CRRs), belonging to DUF26-containing proteins, have been implicated in the defense against fungal pathogens in ginkgo, cotton, and maize. However, little is known about the functional roles of CRRs in the important staple crop wheat (Triticum aestivum). In this study, we identified a wheat CRR-encoding geneTaCRR1through transcriptomic analysis, and dissected the defense role ofTaCRR1against the soil-borne fungiRhizoctonia cerealisandBipolaris sorokiniana, causal pathogens of destructive wheat diseases.TaCRR1transcription was up-regulated in wheat towardsB. SorokinianaorR. cerealisinfection. The deduced TaCRR1 protein contained a signal peptide and two DUF26 domains. Heterologously-expressed TaCRR1 protein markedly inhibited the mycelia growth ofB. sorokinianaandR. cerealis. Furthermore, the silencing ofTaCRR1both impaired host resistance toB. sorokinianaandR.cerealisand repressed the expression of several pathogenesis-related genes in wheat. These results suggest that the TaCRR1 positively participated in wheat defense against bothB. sorokinianaandR. cerealisthrough its antifungal activity and modulating expression of pathogenesis-related genes. Thus,TaCRR1is a candidate gene for improving wheat resistance toB. sorokinianaandR. cerealis.