Analysis On Sucrose Synthase(SuSy) Activity In Developing Cotton Fibers And Its Gene Deduced Amino Acid Sequence

In this reseach, we compared sucrose synthase activity and its mRNA of middle and up bolls among SNFK-6, ZMS-45 and SNZ-1. Meanwhile, its primary and secondary structures were predicted, phylogenetic relationships of Sucrose Synthase multigene family in plants were analyzed by bioinformatical technology. These results are as follows:We examined the role of sucrose synthase in cotton fiber:(1) SuSy activities in middle and up bolls have the same dynamic characteristic in the whole development. It was low at -1DPA, but it increased fastly at 0DPA. Then it declined at 9DPA. It was clearly found that SuSy activity kept higher in fiber cells from 18DPA to 27DPA. As we all know, fiber cell initiation and elongation stage is at 0 DPA, from 18DPA to 27DPA is a stage for rapid cellulose synthesis, so SuSy activity correlates strongly with the degree of fiber initiation,elongation and secondary wall synthesis. (2) During the same stage of fiber development, we compared SuSy activity of middle and up bolls among three varieties, the results were unifom: ZMS-45> SNFK-6> SNZ-1. It was identical with the comparation of their fiber qualities. (3) In the whole development of cotton fiber, SuSy activities of middle and up boll in ZMS-45 were uniform, but SuSy activities of middle bolls were dominantly higher than those of up bolls in SNFK-6, and SNZ-1. (4) The dynamic characteristics of SuSy mRNA during the whole development were identical with the changes of SuSy activity. So sucrose synthase can be a biochemistry marker in cotton breeding.In terms of bioinformatics and by means of http://www.expasy.org., http://www.ch.embnet.org.,NCBI nucleic acid/protein online analytical utility, sucrose synthase gene as well as the structural characteristic of sucrose synthase amino acid sequence was analyzed and predicted in cotton. Meantime, the hydrophilicity, hydrophobicity, signal peptide, transmembrane topological structure, and winded helical structure of sucrose synthase were also discussed. The results showed that sucrose synthase has two helical segments that were 20-30 amino acid sequence and 190-215 amino acid sequence, and did not contained signal peptide; its PI was 6.41; it was a stable non-transmembrane and hydrophilous protein.