Bioinformatics Analysis On ESTs Sequences From Wheat Stripe Rust Resistance SSH CDNA Library

Plant disease resistance is the pathogen interaction and overall performance of plants.In addition to functional genes, the large number of regulatory genes in plant disease resistance also plays an important role. Wheat stripe rust is a significant disease that caused by Puccinia striiformis and it's a serious threat to wheat production. Induced by stripe rust in the original spectrum of research, from genomics to understand the level of resistance of a comprehensive and systematic response to the network relationship between genes, disease resistance on the separation of its regulatory genes and cloning to obtain new molecular markers to improve the comprehensive anti-wheat disease, to explore new ways of guiding significance for breeding.This study constructed a stripe rust resistance of wheat variety CN 19 (including the new stripe rust resistance gene Yr41) for research material, stripe rust pathogen-induced suppression subtractive hybridization based on the SSH cDNA library, through the SSH cDNA library clones were sequenced, and sequencing of ESTs from the effective sequence analysis, functional annotation and classification, and preliminary study of electronic positioning, to study of the levels from the genome of wheat stripe rust disease resistance induced by the molecular mechanism of resistance in wheat to understand disease CN 19 and stripe rust in the interaction of the characteristics of gene expression, identify new genes related to resistance to stripe rust,stripe rust resistance system the molecular mechanism and the cultivation of resistant varieties basis. The main findings are as follows:1. Through the SSH cDNA library sequencing 216 positive clones were obtained 171 valid ESTs.To proteins and nucleic acids with the GenBank database Blast comparison of the sequence of which 161 ESTs with known function,94.2%of total ESTs, an EST with unknown functions,9 ESTs in the database, no sequence similarity. To further understand the function of known ESTs involved in metabolic reactions, according to Bevan and other plant gene function classification (slightly altered), the ESTs in BLAST were divided into eight categories, of which two are the most important defense-related disease genes and housekeeping genes. With defense-related ESTs in resistance, mainly related to oxygen free radical scavenging enzymes (SHMT gene, VTC2 gene), pathogen resistance protein (galactose-binding lectin lectin), disease resistance regulatory genes (STK), hydrolytic enzymes (nitrilase) and secondary metabolism related enzymes (S-adenosylmethionine), etc.; in housekeeping genes, mainly involved in primary metabolism, energy metabolism, cell structure, transport genes, etc.2. By 171 ESTs on the effective sequence clustering and splicing analysis, obtained 57 UniGenes, including 22 contigs (contig) (38.6%) and 35 independent ESTs (singletons) (61.4%), the proportion of independent high, indicating that the access to large number of non-redundant genes. Will be the UniGenes and GenBank database of protein and nucleic acid than Blast, which won 45 UniGenes homology of the total ESTs 78.9%,17.5%have no matching sequences in the database. Was higher than the target sequence UniGenes in 29 (50.9%) and the database at least a high degree of sequence similarity,10 (17.5%), moderate similarity, eight (14.1%), low similarity, and others under the Allona (1998) theory, can be drawn in this study received UniGenes 31.6% of the genes are novel genes, they may play an important role in the disease process, its exact function to be studied further.3. Effective on the 171 ESTs, the bioinformatics methods of electronic positioning, the final total of 34 ESTs were respectively located in addition to 2A,2D,7A and 7B outside the 17 chromosomes, localization rate of 19.9%, of which 21 ESTs at the same time located on the same homologous chromosome ABD on 61.2%of the total ESTs positioning; four ESTs located in the genomes of different sources, accounting for 11.2% of ESTs positioning; 9 ESTs located in the single chromosome, the total positioning ESTs of 27.6%. Positioning results showed that some resistance genes were more accurate positioning to the corresponding chromosome, which for the resistance gene cloning, expression and functional studies provide important information for further study of resistance mechanisms of wheat provided the basic data.