Sequencing and expression analysis of a novel HMW-glutenin gene Kx from Crithopsis delileana / 生物工程学报

Using SDS-PAGE analysis, the High-molecular-weight (HMW) glutenin subunits of two Crithopsis delileana accessions were detected. It was found that the two accessions had the same HMW glutenin subunits. Only one HMW glutenin subunit with the similar electrophoresis mobility to the y-type HMW glutenin subunit of hexaploid wheat was observed in C. delileana. However, It was indicated that this glutenin subunit was an x-type glutenin subunit Kx by gene sequence analysis. The full coding region of Kx gene is 2052bp and could encodes a mature protein with 661 amino acid residues. The Kx gene could be expressed in the bacterial expression system, and the expressed protein had the same electrophoresis mobility as that in the seed of C. delileana. The primary structure of Kx subunit was very similar to the x-type HMW glutenin subunits encoded by the A, B and D genomes of wheat, the C and U genomes of Aegilops, and the R genome of Secale cereale. In the phylogenetic analysis, Kx subunit was clustered together with Ax1 subunit by an interior parallelled branch. In conclsion, Kx gene is a novel x type glutenin subunit gene from C. delileana.

Sequence analysis of alpha-amylase inhibitors genes with resistance to insects in wheat and Aegilops / 生物工程学报

The alpha-amylase inhibitors have been proposed as possibly important weapons against pests. Thus, it is of importance to identify the specificity of them. Based on the EST data of alpha-amylase inhibitor genes that were retrieved from NCBI, BBSRC and GrainGenes, two PCR primers were designed. The coding sequences of 24 kD dimeric alpha-amylase inhibitors with resistance to insects in 17 wheat and Aegilops accessions were investigated and 17 new genes were obtained. Only one 24 kD alpha-amylase inhibitor gene was found in each diploid wheat and Aegilops accession, whereas 8 genes were characterized from one hexaploid wheat variety, indicating that the 24 kD alpha-amylase inhibitors in hexaploid wheat were encoded by multi-gene. The deduced amino acid sequences of 2 genes from common wheat and 1 gene from Ae. tauschii were the same as the sequence of the inhibitor 0.19, and the deduced amino acid sequence of another gene from common wheat was similar to the inhibitor 0.53 with only one amino acid difference. The amino acid sequences of 24 kD dimeric alpha-amylase inhibitors shared very high coherence (91.2%). These results suggest that the alpha-amylase inhibitors in 24 kD family were derived from common ancestral genes by phylogenesis.