Mutation Mechanism Of XiaoYan 81 1Ax1 Subunit Deletion Family Induced By Ion Beam

The Henan Province Key Laboratory of Ion Beam Bioengineering irradiated the triticum aestivum XiaoYan 81 dry seeds with low energy N+, and then we found four types of high molecular weight glutenin subunit deletion mutations, such as lAxl, 1Bx14+1By15, 1Dy12 and 1Dx2+lDyl2 subunit deletion, undergoes four generation of select and breeding, we obtained the high molecular weight glutenin subunit lAxl deletion mutation groups with genetic stability. In this study, the field character of the M3 of high molecular weight glutenin subunit lAxl deletion mutation groups has been carried on the observation, we also analyzed the genetic stability of M4 of the deletion mutation family their mutation mechanisms.1. The agronomic traits of M3There are 25 lines altogether in our High molecular weight glutenin subunits lAxl deletion mutation groups, and the agronomic traits are same as each other within a specific line. Both the full flowering time and the mature time of the M3 are earlier than the wild-type. There are some difference between the M3 and the wild-type in plant height, panicle length, tiller, flag leaf area, plant type, grain weight, grain weight per spike and the grain characteristics. And there are some traits of M3, such as leaf ears, leaf tongue, leaf wax, leaf type, spike color, which are basically consistent with the wild type.2. SDS-PAGE electrophoresis analyze of M4Five seeds per plant were taken randomly to do SDS-PAGE electrophoresis, the HMW-GSs composition analysis of every single plant indicated that the HMW-GS lAxl deletion mutation family are genetic stability, and there is no characters separation. 3. Isolation and sequencing of the silence HMW-GS 1Ax1 geneIn order to study the mutation mechanism of the XiaoYan 81 HMW-GS 1Ax1 deletion mutation family which induced by Ion Beam, we have designed a pair of primers according to the Glu-lAxl gene sequencing information to amplify the Glu-lAxl mutation gene coding region, then post-clone and sequencing and compared with the Glu-lAxl gene sequence of the wild-type.4. sequence characteristics of the silence HMW-GS 1Ax1 geneThe central repeat region of the 1Ax1 subunit mutant gene has a high degree of variation, while the nucleotide variation of the 5'terminal and the 3'terminal non-repeat region is relatively small. The mutation types include gene fragment deletion, base conversion, transversions and deletion, and the main mutation type is base coversion which accounting foe more than 70% of the totle variance, then is base trabsversion which accounting for about 20% of the totle variance. Through the results of our experiment, it can be seen that low energy ion beam inducing mutagenesis have a wider spectrum.5. The molecular mechanism of the HMW-GS 1Ax1 gene silencingIn these three mutation families, because of the mutations, there appeared several premature termination codons which allowing the protein encoded by the mutant gene early termination in the silencing HMW-GS 1Ax1 gene, resulting in the lack of 1Ax1 subunits.