Molecular Identification Of Wheat Xylanase Inhibitors And Mutation Analysis Of TLXI Gene Sequences

Xylan enzyme inhibitors genes is are important defense genes,playing significant role in plants defense disease response, with certain reference value for wheat breeding for disease resistance. The three xylanase inhibiting proteins genes TAXI-I,XIP-I, TLXI were detected and identificated respectively by6specific primers in260varieties of wheat (strains) from all over the country, and their powdery mildew disease indexes in the field had been counted., The distribution of three genes in the wheat strains was counted, TLXI xylanase inhibitors gene sequences were sequenced in the different wheat varieties. The three kinds of xylanase inhibitors genes and TIXI gene sequence of single nucleotide variation were researched by combining with the field of record of powdery mildew disease index.Through the molecule detection of the three xylanase inhibitors genes, the distribution of three xylanase inhibitors genes in the different260in a material showed that:13materials only contain TAXI-I gene, accounting for0.05%,36materials only contain XIP-I gene, accounting for13.9%,29materials only contain TLXI gene, accounting for11.2%,23materials only contain XIP-Land TAXI-I genes,55materials only contain XIP-Iand TLXI genes,41materials only contain TAXI-Iand TLXI genes,35materials contain XIP-I, TAXI-Iand TLXI genes,23materials do not contain the three genes. Three genes are not alone, some varieties also contains two or three genes.The analysis of three gene and the disease index showed that average disease index of varieties only containing TAXI-I gene was6.8, average disease index of varietie only containing XIP-I gene was12.41, average disease index of varieties only containing TLXI was11.53, average disease index of varietie only containing TAXI-I and XIP-I genes was8.9, average disease index of varietie only containing XIP-I and TLXI genes was11.4, average disease index of varietie only containing TAXI-I and TLXI genes was8.2, average disease index of varietie only containing TAXI-I, XIP-I and TLXI genes was12.3,average disease index of varieties without the three genes was11.4.So average disease index of varieties only containing TAXI-I gene (6.8) was significant different with the average disease index of varieties without the three genes (11.4),with others no significant difference..These preliminary results showed TAXI-I gene may be an effective powdery mildew resistance gene, play a role in the wheat.The sequenced TLXI gene sequences of48varieties with high and low disease index showed that the genetic coding areas appeared single nucleotide mutations, existing three SNPs (135bp G/A,159bp A/C,168bp G/C), five varieties appeared terminate anticodon mutations (135bp G/A) with159bp A/C and168bp G/C mutations,8varieties had159bp A/C mutations,3varieties had159bp A/C and168bp G/C mutations. Combined with disease index, the average disease index of varieties containing159bp A/C and168bp G/C mutations was lower(9.07) than nun-mutation (average disease index was12.56) by27.8%, significantly different; average disease index of varieties only containing159bp A/C mutations was14.79, and average disease index of non-mutation was12.56, higher by17.8%. These preliminary results showed TLXIgene mutations (159bp A/C and168bp G/C) may influence of TLXI gene resistance.