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| Genes Expression in Response to Re-watering after Drought Stress in Shaan 229 and Characterization of Ethylene Receptor Genes (TaERS) in Wheat |
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Abstract To explore more genes for the improvement of drought-tolerance and water use efficiency in crops, the differential gene expression during re-watering after serious drought stress in common wheat (Triticum aestivum L.) was investigated by constructing SSH-cDNA library with the seedlings of Shaan 229 as materials. A total of 59 positive clones with insertions more than 400 bp were randomly picked from the library and sequenced. Then redundancy sequences were removed, finally 32 high quality EST (GenBank accessions of ES466767~ES466798) were identified. Homologous comparison of those EST sequences indicated that there were some similar responses of wheat to re-watering after serious drought stress with that to the other abiotic stresses. Among the 32 EST identified, 17 EST sequences were similar to known genes encoding functional proteins, which involved in the signal transduction, energy metabolism and transcriptional regulation, etc., the others were new EST in wheat. Based on an EST sequence highly similar to ERS gene in the SSH-cDNA library, four cDNA sequences encoding ethylene receptor in wheat were isolated using RT-PCR and RACE approaches. All the deduced proteins of these four cDNA sequences had the typical domains of ERS (three transmembrane segments, GAF domain, HisKA and HATPase-c domain). The full-length cDNA sequence of TaERS genes in wheat were 2 090, 2 271, 2 216 and 1 886 bp, and designated as TaERS1 (HM347272), TaERS2 (HM601437), TaERS3(HM601438) and TaERS4 (HQ111523), respectively. Multiple sequence alignment analysis based on the amino acids encoded by the ERS genes from wheat (T. aestivum L.), rice (Oryza sabiva), corn (Zay mays), sugarcane (Saccharum officinarum), Arabidopsis (Arabidopsis thaliana), tobacco (Nicotiana tabacum) and tomato (Lycopersicoum esculentum) indicated that TaERS had the highest similarity with that of rice (93%). The sequence alignment analysis revealed 23 SNPs among the four cDNA sequences of TaERS genes in wheat. Real-time PCR analysis indicated that TaERS was up-regulated in wheat by water stress and re-watering, and suggested that TaERS genes might be involved in responses of wheat to water stress. Those results may be beneficial for understanding the gene expression network of wheat in response to re-watering after drought stress and further characterization of the function of TaERS genes in improving the drought tolerance and water use efficiency in wheat.
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Received: 30 November 2011
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