Water stress and cold stress are important factors restricting plant growth.However,there is little knowledge on the function of stress-responsive genes in plants.Therefore,it is necessary to clone some important genes to study the mechanism of plant adaptation to abiotic stress for improvement of plant resistance.A putative water stress-induced gene,W89,was cloned from the cDNA library of drought-treated wheat seedlings by phage hybridization in situ,and its entire length was obtained using 5′-rapid amplification of cDNA ends(RACE)and reverse transcription-polymerase chain reaction(RT-PCR).The full-length cDNA of W89 consists of 2 392 bp and contains a 1 896 bp open reading frame(ORF) encoding a 631 amino acid protein.Southern blot analysis indicated that W89 was a single-copy gene.RT-PCR analysis revealed that the expression of W89 was upregulated by drought,cold,and abscisic acid(ABA).Amino acid sequence analysis discovered that W89 had a conserved region of DUF248(pfam03141),which contained a methyltransferase domain with a sterile alpha motif(SAM)-binding motif.Phylogenetic analysis showed that W89 was 66%identical to Oryza sativa dehydration-responsive protein(BAD67956).It was supposed that W89 was a novel dehydration-responsive protein encoding gene.On the basis of the functions of methyltransferase and the SAM-binding motif,the SAM-binding motif of W89 was supposed to be connected with other proteins or transcription factors to transduce stress signals and finally regulate the expression of stress-responsive genes on the early stage of drought stress.
ZHANG Rui-yue XU Zhao-shi LI Lian-cheng CHEN Ming MA You-zhi
