SNPs Divergence In Fiber Development-related Genes And Indentification Of Sucrose Synthase Gene Fragment In Gossypium Hirsutum L.

Cotton fiber is the important textile material, plays an important role in our national economy. The high fiber quality is one of the major goals in the cotton breeding of the world. So, it is important to elucidate fiber development process and major factors related to fiber quality by molecular biology. The research results are listed as follows: 1.SNPs divergence in fiber development-related genesWith the PCR-based method, we isolated sequences of five fiber development- related genes from seven allotetraploid cotton materials with different fiber quality and two diploid progenitors. The result of sequences alignment indicated that for SuSy, Expansion and LTP genes, the amplicons from allotetraploid cotton materials can be divided into two kinds of copies: the locus in A genome and the locus in D genome; but for ACP and FbL2A genes, the amplicons from allotetraploid cotton materials can not be divided into two kinds.We caculated the quantity of the SNPs and the SNPs frequency in A and D genome, respectively. The SNPs frequency of A genome is 0.0055. The SNPs frequency of D genome is 0.0082.In the accessions of upland cotton with high fiber quality, we found four cSNPs with nonsynonymous substitute, which may have phenotype effect. 2.Cloning and characterization of the sucrose synthase gene fragment in cottonOn the basis of an fiber cDNA segement, we had isolated a novel sucrose synthase gene fragment in cotton genome by the method of TAIL-PCR. The gemomic DNA fragment has an length of 2.9 kb, contains initial exon, other seven exons and eight introns. The BLAST result indicated that this gene was high homologous to citrus sucrose synthase gene-CitSUSA(GenBank accession, AB022091). So, we designated this cotton sucrose synthase gene as GhSUSAl. The GhSUSAl gene preferentially expressed in ovule and fiber cells since six days post-anthesis, which indicated it might be involved in the transcription regulation of genes during cotton fiber elongation development.