Gene Expression Proflie Induced By Water Stress In Wheat Seedling Using Suppression Subtractive Hybridization

Wheat is a staple crop in the majority of countries; however its yield has been limited dramatically by drought. Therefore, it is urgent to study the drought-tolerant mechanism in the integral level and to improve drought tolerance in wheat using advanced biotechnology. In this research, Hanxuan 10, a wheat cultivar with strong drought tolerance was employed as the plant material. A cDNA library induced by water stress with 1920 individual recombinant clones was constructed by the method of suppression subtractive hybridization (SSH). Based on the sequencing data, we obtained a total of 1131 good quality ESTs. Querying the database of GenBank, the results revealed that most of the ESTs were high homologous with the cDNA fragments in dbEST, and more than 73% of these cDNA fragments originated from the cDNAs induced by abiotic or biotic stresses in plants such as drought, heat, salt, cold, aluminum stress, pathogen-infected, ABA-treated and so on. More than 55% ESTs showed high homology with cDNA fragments simultaneously induced by several kinds of stress. It implied that abiotic or biotic stresses affected directly or indirectly water metabolism in plants, and there were some shared pathways in the response to all stresses in plants. Blastx and Blastn analysis revealed that 786 ESTs were known function and the rest 345 ESTs were unknown function in the GenBank NR database. There were 202 Uni-ESTs, which including 134 contigs and 68 singletons based on EST cluster result. The known function Uni-ESTs belonged to 81 categories that involved in many kinds of metabolism pathway. The gene numbers that participated in metabolism, disease/defense, energy and signal transduction were more. The results indicated that many physiology and biochemistry pathways were involved in the drought tolerance in plant. In addition, these gene products included two classifications. One is functional protein, such as lipid transfer protein, cysteine proteinase that protected the cell directly. Another is regulatory protein, such as transcription factor, which was likely to participate in interacting with genes response to dehydration and protected cell indirectly. Based on the analysis of the expressing genes, the gene expression profile induced by water stress in wheat seedling had been preliminarily constructed.