| Three cultivars were studied about Fengkang 6, Zhongmiansuo 45 and Shannong Brown 02 in leaves and fibres from flowing to boll opening by determining sucrose content, soluble sugar content and the activity of Sucrose Phosphate Synthase (SPS), e-cloing the fragment of SPS gene, observing mRNA expression of SPS gene fragment and doing bioinformatics analysis. The results are as follows:1. The activity of SPS, soluble sugar content and sucrose content appeared double peaks on blooming day and 18 days post anthesis (DPA) in leaves and fibres; the first peak surpassed the second peak and it decreased as a whole. The value of SPS activity was the highest in Fengkang 6, second in Zhongmiansuo 45, and third in Shannong Brown 02. And simultaneously soluble sugar content and sucrose content had the same changes.2. SPS activity was higher in leaf than in fibre, which was showed that SPS was mainly concerned with sucrose synthsis in leaf. SPS activity in cotton fibre was increased during fiber secondary wall deposition, and this shew that SPS played an important role during fiber secondary wall deposition.3. RT-PCR analysis of SPS gene fragment showed that SPS gene expression of the three cultivars'transcriptional level was higher in leaf than in fibre during cotton fibre development. And this included that SPS gene expression maily reacted in sourse leaves. In leaf and fibre SPS expression was the highest in Fengkang 6, second in Zhongmiansuo 45, third in Shannong Brown 02.4. SPS gene fragment was named e-cloning sequence and was 1050 bp by e-cloning technique. While cexu sequence from experiment was 980bp through designing primer according to e-cloning sequence. There was 80% identity of nucleic acid sequence and 75% identity of amino acid sequences between e-cloning sequence and cexu sequence. The homology was 60%-68% among cexu amino acid sequences and other plants amino acid sequences, suca as mandarin orange, horsebean, potato, sugarbeet, chrysanthemum and... |
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