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Manipulation of Fiber Quality in Transgenic Cotton via Ectopic Expression of Fiber Genes

R. Mishra, N. R. Yadav and T. A. Wilkins


 
ABSTRACT

Advances in cotton biotechnology and gene discovery are making the selection and manipulation of fiber genes for the improvement of yield and fiber quality a reachable goal . To test the potential for altering fiber properties, the expression of expansin, a cell wall enzyme involved in fiber elongation, was altered in transgenic cotton plants. Four different gene constructs were assembled, in which the expansin gene was cloned in the sense or antisense (RNAi) orientation under the control of two different promoters B a cotton promoter or the CaMV 35S constitutive promoter. The genes were introduced into G. hirsutum L. cv. Coker-312 by Agrobacterium- mediated transformation. Variations in the number and density of leaf and stem hairs (trichomes), flower morphology (anthers and stigma), leaf size and shape, and fiber quality were observed relative to control plants, depending on the gene construct. Transgenic cotton plants containing the 35S::expansin gene construct exhibited increased fiber strength, fiber tenacity and fiber weight/seed (yield).

A fiber expansin cDNA was placed under the transcriptional control of a cotton V-ATPase promoter in the sense (TW 317) or anti-sense (TW 318) orientation and cloned into the binary vector pBl101.1. The chimeric gene construct was introduced into Agrobacterium tumefaciens strain LBA4404 by electroporation. Bacterial colonies were selected using 50 µg/ml kanamycin (plasmid selection) and 100µg/ml streptomycin (Agrobacterium selection).

A second set of expansin constructs were assembled using the 35S CaMV promoter to produce sense (TW 321) and anti-sense (TW 319) chimeric genes, which were subsequently cloned into the binary vector pDVS572 and transformed Agrobacterum LBA4404 using electroporation. Bacterial colonies were selected using 15µg/ml tetracycline (plasmid selection) and 100µg/ml streptomycin (Agrobacterium selection).





Reprinted from Proceedings of the 2001 Beltwide Cotton Conferences pp. 1437 - 1439
©National Cotton Council, Memphis TN

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Document last modified XXXXXX, XXX XX 2001