[Show abstract][Hide abstract] ABSTRACT: The capacity of conventional breeding to simultaneously improve the yield and quality of cotton fiber is limited. The accumulation of the plant hormone indole-3-acetic acid (IAA) in cotton fiber initials prompted us to investigate the effects of genetically engineering increased IAA levels in the ovule epidermis. Targeted expression of the IAA biosynthetic gene iaaM, driven by the promoter of the petunia MADS box gene Floral Binding protein 7 (FBP7), increased IAA levels in the epidermis of cotton ovules at the fiber initiation stage. This substantially increased the number of lint fibers, an effect that was confirmed in a 4-year field trial. The lint percentage of the transgenic cotton, an important component of fiber yield, was consistently higher in our transgenic plants than in nontransgenic controls, resulting in a >15% increase in lint yield. Fiber fineness was also notably improved.
[Show abstract][Hide abstract] ABSTRACT: To investigate the expression pattern of GhSCFP which was isolated from cotton fiber cDNA library, a 1006 bp upstream fragment of the gene was cloned by chromosome walking
and fused to GUS and GFP respectively. Histochemical GUS and GFP fluorescence analysis revealed that the expression of the report genes driven by
the promoter sequence was detectable only in outer layer cells during the seed development in the transgentic tobaccos. In
transgenic cotton, strong GUS activity was observed in spherical protrusions on 0 dpa (days post anthesis) ovule surface,
and in the 2–36 dpa fiber cells, while no GUS signals were detected in the root, leaves, stem, corolla, anther and stigma.
Our data demonstrated that GhSCFP upstream sequence is a cotton fiber-specific promoter and this promoter will be useful in the molecular research on fiber
cell development and in cotton fiber improvements by genetic modification.
Chinese Science Bulletin 08/2008; 53(17):2639-2645. · 1.37 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Here we report the effect of the 35S promoter sequence on activities of the tissue- and organ-specific gene promoters in tobacco plants. In the absence of the 35S promoter sequence the AAP2 promoter is active only in vascular tissues as indicated by expression of the AAP2:GUS gene. With the 35S promoter sequence in the same T-plasmid, transgenic plants exhibit twofold to fivefold increase in AAP2 promoter activity and the promoter becomes active in all tissue types. Transgenic plants hosting the ovary-specific AGL5:iaaM gene (iaaM coding an auxin biosynthetic gene) showed a wild-type phenotype except production of seedless fruits, whereas plants hosting the AGL5:iaaM gene along with the 35S promoter sequence showed drastic morphological alterations. RT-PCR analysis confirms that the phenotype was caused by activation of the AGL5:iaaM gene in non-ovary organs including roots, stems and flowers. When the pollen-, ovule- and early embryo-specific PAB5:barnase gene (barnase coding a RNase gene) was transformed, the presence of 35S promoter sequence drastically reduced transformation efficiencies. However, the transformation efficiencies were restored in the absence of 35S promoter, indicating that the 35S promoter might activate the expression of PAB5:barnase in non-reproductive organs such as calli and shoot primordia. Furthermore, if the 35S promoter sequence was replaced with the NOS promoter sequence, no alteration in AAP2, AGL5 or PAB5 promoter activities was observed. Our results demonstrate that the 35S promoter sequence can convert an adjacent tissue- and organ-specific gene promoter into a globally active promoter.