ABSTRACT
Two cotton (Gossypium hirsutum L.) genes, ghprp1 and ghprp2, encoding cell wall proline-rich proteins (PRPs) have been cloned and characterized. The ghprpl gene has an open reading frame (ORF) that encodes a PRP of 299 amino acids (aa), whereas the ghprp2 gene contains an ORF that codes for a 310-aa PRP. The GhPRP1 has an 80% identity in aa sequence with that of GhPRP2. Like other plant cell wall PRPs, both cotton PRPs have a hydrophobic signal peptide at their N-termini, followed by repeating peptide units. Northern blot analyses showed that the ghprpl gene is predominantly expressed in the fiber during the elongation stage of fiber development. Reverse transcription (RT)-PCR analysis showed that ghprpl is expressed in both fiber and root tissues, whereas ghprp2 is in roots only. The ghprpl gene was shown to be present in the A1, A2, D1 and D5 genomes of Gossypium by PCR amplification, whereas the ghprp2 gene is only present in the A1 and A2 genomes. The ghprpl gene was over-expressed in the yeast Pichia pastoris, and the expressed GhPRP1 protein was used as an antigen to raise polyclonal antibodies (anti-GhPRP1). Western analysis using the anti-GhPRP1 probe detected a major protein band (50 kDa) in 5-31-day postanthesis (DPA) fibers. However, the 50 kDa protein was absent in other cotton tissues.
Subject(s)
Gossypium/genetics , Plant Proteins/genetics , Amino Acid Sequence , Base Sequence , Cell Wall/metabolism , Cloning, Molecular , Gossypium/metabolism , Molecular Sequence Data , Plant Proteins/metabolism , Sequence Analysis, DNAABSTRACT
A cotton Ltp3 gene and its 5' and 3' flanking regions have been cloned with a PCR-based genomic DNA walking method. The amplified 2.6 kb DNA fragment contains sequences corresponding to GH3 cDNA which has been shown to encode a lipid transfer protein (LTP3). The gene has an intron of 80 bp which is located in the region corresponding to the C-terminus of LTP3. The Ltp3 promoter was systematically analyzed in transgenic tobacco plants by employing the Escherichia coli beta-glucuronidase gene (GUS) as a reporter. The results of histochemical and fluorogenic GUS assays indicate that the 5' flanking region of the Ltp3 gene contains cis-elements conferring the trichome specific activity of Ltp3 promoter.
Subject(s)
Carrier Proteins/genetics , Genes, Plant , Gossypium/genetics , Promoter Regions, Genetic , Amino Acid Sequence , Antigens, Plant , Base Sequence , Carrier Proteins/chemistry , Cloning, Molecular , DNA, Complementary/biosynthesis , DNA, Complementary/chemistry , Molecular Sequence Data , Plant Proteins , Plants, Toxic , Textiles , Nicotiana/geneticsABSTRACT
A cotton genomic library was screened using a fiber-specific cDNA (GH3) encoding a lipid transfer protein (LTP). One genomic clone (1.7 kb DNA insert) containing the Ltp gene (Ltp6) was sequenced and characterized. The Ltp6 contains an open reading frame of 360 bp, which is interrupted by a single intron (136 bp) located in the region corresponding to the C-terminal of the protein. The derived amino-acid sequence of LTP6 is 64% homologous to that of GH3. Like the GH3 gene, the Ltp6 is specifically expressed in fiber cells in a temporal manner. However, its expression level is lower than that of GH3.
Subject(s)
Carrier Proteins/genetics , Genes, Plant , Plant Proteins/genetics , Soybean Proteins , Amino Acid Sequence , Antigens, Plant , Base Sequence , Cloning, Molecular , DNA, Complementary/genetics , DNA, Plant/genetics , Gene Expression , Gossypium/genetics , Introns , Molecular Sequence Data , Open Reading Frames , Sequence Homology, Amino AcidABSTRACT
A full-length cDNA clone, GH3, has been isolated from a cotton fiber cDNA library using a differential screening method. The nucleotide and derived amino acid sequence data show that GH3 encodes a lipid transfer protein (LTP) of 120 amino acids. The presence of a transmembrane signal peptide at the N-terminal of the protein would suggest its possible outer cellular location in fiber cells. Northern analysis indicates that the GH3 gene is developmentally regulated.
Subject(s)
Carrier Proteins/genetics , Gene Expression Regulation, Developmental , Gene Expression Regulation, Plant , Gossypium/genetics , Amino Acid Sequence , Antigens, Plant , Base Sequence , DNA, Complementary , Gossypium/growth & development , Molecular Sequence Data , Plant Proteins , Sequence Homology, Amino AcidSubject(s)
Polysaccharides , Zea mays , Carbohydrate Metabolism , Carbon Dioxide/metabolism , Carbon Isotopes , Genes , Genetics , Genotype , Glucosyltransferases/metabolism , Glycogen Synthase/metabolism , Hexoses/metabolism , Models, Chemical , Mutation , Nucleoside Diphosphate Sugars , Nucleotidyltransferases/metabolism , Polysaccharides/metabolism , Seeds/enzymology , Seeds/growth & development , Seeds/metabolism , Species Specificity , Starch/biosynthesis , Zea mays/enzymology , Zea mays/growth & development , Zea mays/metabolismABSTRACT
On the basis of interallelic recombination frequencies measured in diallelic crosses of the 5 amylose-extender alleles in maize, ae, B1, B3, M2 and i1, it was possible to construct a unique linear genetic map ordering all 5 alleles within the locus. The reciprocal diallelic crosses each gave comparable frequency estimates. The relative order is ae, i1, B3, B1, M2 or the reverse. Even though F1 endosperms resulting from all possible diallelic crosses were phenotypically mutant, therefore non-complementing, no decision as to whether or not these alleles exhibit functional complementation should be made without biochemical characterization of the starches from the various heteroallelic genotypes.
