Cloning,Characterization And Mapping Of Four Genes Related With Fiber Development In Gossypium Hirsutum L.

Cotton is the most prevalent natural fiber used as the raw materials in textileproduction, and is one of the most important oil crops in the world. Each cotton fiber is asingle cell of ovule epidermis that elongates to 2.5-3.0 cm within approximately 16 dayspost anthesis (DPA), and its elongation is not relevant to cell division. So cloning thedevelopmentally regulated genes from cotton fibers may play an important role not only inimproving the quality of cotton fiber, but also in elucidating the mechanism of plant celldevelopment and cellulose biosynthesis. Genechips were performed with the wild li₁ and itsLigon lintless mutant line Li₁ segregated from the self-crossing progenies of the Ligonlintless mutant line Li₁ to isolate genes preferentially expressed during elongating forproviding the mechanism of cotton fiber rapid elongation.Four cDNA clones were separated from cotton fiber library of elite quality material7235 during fiber elongation and the secondary thicking by genechips with probes of the4DPA ovule-fiber compound from the wild li₁ and the Ligon lintless mutant line Li₁. The fulllength of G019B11A is 1502bp with 1170bp ORF coding 389 amino acids. It shares highhomology with chalcone synthase genes from other plants, and was named GhCHS. Thefull length of G043H11 is 1547bp with 1182bp ORF coding 393 amino acids. It shares highhomology with S-adenosylmethionine synthetase genes from other plants, and was namedGhSAMS. The full length of G026DO8A is 1418bp with 1158bp ORF coding 385 aminoacids. It shares high homology with nodulin genes, and was named GhNLP. The fulllength of G055H06A is 788bp with 378bp ORF coding 125 amino acids. It shares highhomology with cysteine proteinase inhibitor genes from other plants, and was namedGhCPI.Subsequent RT-PCR analysis indicated that the expression quantity of GhCHS,GhSAMS, GhNLP and GhCPI were less in the wild line li₁ than that in the Ligon lintlessmutant line Li₁ at 4DPA. The expression of GhCHS was consecutive. GhSAMS wasexpressed obviously more at 0DPA than other phases both in the wild line li₁ and the Ligonlintless mutant line Li₁. The expression of GhNLP in the wild line li₁ was almostly none in root, stem and leaf, but was more at 0DPA than other phases. It slowly climbed after0DPA then dropped at 10DPA. In the Ligon lintless mutant line Li₁ the expression climbedobviously by developing but descended at 10DPA. GhSAMS was expressed weakly at0DPA and 2DPA in both types, and highly during subsequent periods.The result of Southern blotting indicated that there are two copies of all the four genesin the genome of upland cotton.We have used the BC₁ mapping population derived from the hybridization between theupland cultivar TM-1 and the island cultivar Hai7124, further TM-1 as recurrent parent.GhSAMS and GhNLP were localized on the chromosome D2 and D5 respectively.