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 eDNA library of drought-treated wheat seedlings by phage hybridization in situ, and its entire length was obtained using 5＇-rapid amplification of eDNA ends （RACE） and reverse transcription-polymerase chain reaction （RT-PCR）. The full-length eDNA 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
