Progress in Functional Genomics of Disease Resistance Genes in Wheat

Bread wheat (Triticum aestivum L.) is a major staple crop in the world. Fungal diseases, such as sharp eyespot, Fusarium head blight (scab), common root rot, and take-all, are impacting negatively wheat production around the world. Breeding resistant wheat varieties is an effective and environmentally safe approach to control diseases. To improve wheat resistance to these diseases, it is vital to identify important genes in these defense responses and to study their roles through functional genomics. Firstly, the resistance-related genes were mined based on differential expressing sequences between resistant and susceptible wheat genotypes using the microarray analysis, RNA-seq and bioinformatics analyses. Then, the defense roles of these genes were studied through evaluating the disease resistance of silencing wheat plants generated by BSMV-based virus-induced gene silencing (VIGS) and overexpressing transgenic wheat lines. Using this strategy, certain wheat genes encoding kinases and transcription factors have been identified as being positive contributors to wheat resistance to sharp eyespot, common root rot, and take-all. For example, the wheat ERF transcription factor TaPIE1 has been isolated and proven to positively regulate resistance to Rhizoctonia cerealis (the pathogen of sharp eyespot). The wheat MYB transcription factor TaPIMP1 has been isolated and revealed to mediate resistance to Bipolaris sorokiniana (the pathogen of common root rot). The wheat AGC kinase TaAGC1 has been identified and shown to be a positive contributor to wheat resistance to Rhizoctonia cerealis. These techniques including genomic sequence, RNA-seq, VIGS and transformation can also be applied to study the interaction between wheat and pathogens.