| Powdery mildew, caused by Erysiphe graminis DC. f.sp.tritici Marchal, is one of themajor diseases of common wheat worldwide. Development and utilization of wheat cultivarswith resistance genes is an efficient, economic and environmentally safe strategy to controlpowdery mildew. Many powdery mildew resistance genes had already lost their resistanceeffect because of variation of prevalent races. So cloning powdery mildew resistance-relatedgenes will play an important role in disease resistance breeding in the future.In this study, we constructed a suppression subtractive hybridization cDNA library withcDNA from wheat germplasm SN6306leaves inoculated with Blumeria graminis as the testerand cDNA from uninoculated SN6306leaves as the driver. A number of differentialexpression genes involved in photosynthesis, protein synthesis, glycometabolism anddisease-resistant were obtained based on the subtractive library of wheat material SN6306. Atotal of eighteen expressed sequence tags (ESTs) were highly homologous with knownproteins involved in disease resistance and defense reactions.A novel gene of TaPrxQ was cloned from wheat material6306through the constructionof subtractive library. Bioinformatics softwares were used to analyse the cDNA and proteinsequence of TaPrxQ. Sequence analysis showed that the ORF of TaPrxQ with no introns is927bp and codes308amino acids. The theoretical molecular mass of the encoded protein is32.4kDa with a calculated pI of9.41. The phylogenetic tree showed that the putativepolypeptide of TaPrxQ is highly similar to HvPrxQ, up to88%identity, and belongs to PrxQfamily.Protein modification by ubiquitin (Ub) and ubiquitin-like proteins (Ubls) is one of themost complex and intensely studied mechanisms of posttranslational protein regulation ineukaryotes, and plays diverse roles in the regulation of numerous biological pathways. A newscreened gene named TaRUB1which is648bp has a high degree of similarity to othermembers of the plant related-to-ubiquitin (RUB) protein genes in both nucleic and amino acidlevels. The genomic sequence of this gene was obtained. It was interrupted by two intronswhich were1450and111bp respectively. The cDNA contained an open reading frame of462bp encoding153amino acids. The predicted protein is a fusion protein with ubiquitin-codingregion and related-to-ubiquitin region. TaRUB1belongs to the family of wheat UBR genes.Results of qRT-PCR showed that TaRUB1is upregulated in leaves infected with powdery mildew at the early stage. Furthermore, the overexpression of TaRUB1in transgenicArabidopsis showed that TaRUB1enhances plant tolerance to biotic and osmotic and saltstress. It implied that TaRUB1has multiple functions in plant abiotic and biotic stresstolerance. |
