The seed_specific phaseolin promoter (Ph/P) was fused to an ipt gene, then was cloned to a plant expression vector containing a gus gene driven by a 35S promoter. Cotton (Gossypium hirsutum L.) plants were tr...The seed_specific phaseolin promoter (Ph/P) was fused to an ipt gene, then was cloned to a plant expression vector containing a gus gene driven by a 35S promoter. Cotton (Gossypium hirsutum L.) plants were transformed through pollen tube pathway methods. After seed germination, histochemical staining of the roots demonstrated that 32 GUS positive plants were obtained and three of which contained the chimeric Ph/P_ ipt transgene as confirmed by PCR analysis. An immunosorbent assay showed that two of the three transgenic cotton lines contained higher levels of zeatin equivalents in seeds than the control. Seedling development of these two transgenic lines differed from the control in a reduction of the shoot growth, showing a stunted phenotype as expected, but a surprisingly developed root system with a 3-4 fold fast_growing lateral roots. In addition, fibers (seed_hairs) of the two transgenic cotton lines were considerably shorter than those of the control. These results indicate that genetic engineering may be used to manipulate the development of cotton plants, particularly cotton fibers.展开更多
A fuzzless-lintless (fl) seed mutant of Gossypium hirsutum L. cv. Xu-142 was investigated to study cotton fiber development. Scanning electron microscopy revealed that fiber initials were virtually absent from fl ovul...A fuzzless-lintless (fl) seed mutant of Gossypium hirsutum L. cv. Xu-142 was investigated to study cotton fiber development. Scanning electron microscopy revealed that fiber initials were virtually absent from fl ovules. RT-PCR analysis showed that the steady-state levels of transcripts of the fiber-specific E6 and Expansin genes were high in wild type (WT) ovules during the fiber initiation and elongation stages, and peaked around 15 days post anthesis (DPA), but only a trace amount of these transcripts was detectable in fl ovules of alt developmental stages investigated. CotmybA, a member of the Myb family, exhibited a clear expression in developing WT ovules, but the expression was abnormal in fl ovules. Application of GA3, or GA3 plus IAA, to the culture medium rescued in vitro fiber initiation and growth of fl ovules only partially. In addition, transcription of E6 and Expansin genes of in vitro cultured WT and fl ovules responded similarly to exogenous hormones. The hormones had less effect on CotmybA transcription in ovules cultured in vitro, and again the WT and fl ovules showed a similar expression. These results suggest that the abnormal or extremely low level of expression of E6, Expansin and CotmybA genes in developing fl seeds is related to the absence of seed-hairs, and the mechanism underlying needs further investigation.展开更多
A cDNA library was constructed using poly (A)+ RNA isolated from -1—15 DPA fibers of upland cotton (Gossypium hirsutum). The cDNA encoding a b-tubulin isoform (designated as GhTub1) was identified through EST search....A cDNA library was constructed using poly (A)+ RNA isolated from -1—15 DPA fibers of upland cotton (Gossypium hirsutum). The cDNA encoding a b-tubulin isoform (designated as GhTub1) was identified through EST search. Northern blot analysis using 3′-UTR of the cDNA as a gene-specific probe was performed to investigate the expression levels of GhTub1 in various organs and in the developing fibers. The results showed that GhTub1 gene was specifically ex-pressed in cotton fiber cells. During fiber development, GhTub1 transcripts accumulated highly at the stage of cell rapid elongation with the highest expression appearing at the time when fiber ex-pansion reaches the peak rate. To probe the in vivo function of GhTub1, its cDNA was cloned in the yeast expression vector pREP1 and transformed into the fission yeast Schizosaccharomyces pombe. Overexpression of GhTub1 in yeast cells caused severe changes in the cell morphology. These results suggest that GhTub1 may play a role in the polar elongation of cotton fibers. To our knowledge, this is the first report on the fiber-specific transcript accumulation of a cotton b-tubulin gene.展开更多
文摘The seed_specific phaseolin promoter (Ph/P) was fused to an ipt gene, then was cloned to a plant expression vector containing a gus gene driven by a 35S promoter. Cotton (Gossypium hirsutum L.) plants were transformed through pollen tube pathway methods. After seed germination, histochemical staining of the roots demonstrated that 32 GUS positive plants were obtained and three of which contained the chimeric Ph/P_ ipt transgene as confirmed by PCR analysis. An immunosorbent assay showed that two of the three transgenic cotton lines contained higher levels of zeatin equivalents in seeds than the control. Seedling development of these two transgenic lines differed from the control in a reduction of the shoot growth, showing a stunted phenotype as expected, but a surprisingly developed root system with a 3-4 fold fast_growing lateral roots. In addition, fibers (seed_hairs) of the two transgenic cotton lines were considerably shorter than those of the control. These results indicate that genetic engineering may be used to manipulate the development of cotton plants, particularly cotton fibers.
文摘A fuzzless-lintless (fl) seed mutant of Gossypium hirsutum L. cv. Xu-142 was investigated to study cotton fiber development. Scanning electron microscopy revealed that fiber initials were virtually absent from fl ovules. RT-PCR analysis showed that the steady-state levels of transcripts of the fiber-specific E6 and Expansin genes were high in wild type (WT) ovules during the fiber initiation and elongation stages, and peaked around 15 days post anthesis (DPA), but only a trace amount of these transcripts was detectable in fl ovules of alt developmental stages investigated. CotmybA, a member of the Myb family, exhibited a clear expression in developing WT ovules, but the expression was abnormal in fl ovules. Application of GA3, or GA3 plus IAA, to the culture medium rescued in vitro fiber initiation and growth of fl ovules only partially. In addition, transcription of E6 and Expansin genes of in vitro cultured WT and fl ovules responded similarly to exogenous hormones. The hormones had less effect on CotmybA transcription in ovules cultured in vitro, and again the WT and fl ovules showed a similar expression. These results suggest that the abnormal or extremely low level of expression of E6, Expansin and CotmybA genes in developing fl seeds is related to the absence of seed-hairs, and the mechanism underlying needs further investigation.
基金supported by the National Natural Science Foundation of China(Grant No.39880014)National Special Program for Research and Industrialization of Transgenic Plants(Grant No.J99 A 003).
文摘A cDNA library was constructed using poly (A)+ RNA isolated from -1—15 DPA fibers of upland cotton (Gossypium hirsutum). The cDNA encoding a b-tubulin isoform (designated as GhTub1) was identified through EST search. Northern blot analysis using 3′-UTR of the cDNA as a gene-specific probe was performed to investigate the expression levels of GhTub1 in various organs and in the developing fibers. The results showed that GhTub1 gene was specifically ex-pressed in cotton fiber cells. During fiber development, GhTub1 transcripts accumulated highly at the stage of cell rapid elongation with the highest expression appearing at the time when fiber ex-pansion reaches the peak rate. To probe the in vivo function of GhTub1, its cDNA was cloned in the yeast expression vector pREP1 and transformed into the fission yeast Schizosaccharomyces pombe. Overexpression of GhTub1 in yeast cells caused severe changes in the cell morphology. These results suggest that GhTub1 may play a role in the polar elongation of cotton fibers. To our knowledge, this is the first report on the fiber-specific transcript accumulation of a cotton b-tubulin gene.
