Style-specific and developmentally regulated accumulation of a glycosylated thaumatin/PR5-like protein in Japanese pear (Pyrus serotina Rehd.).
The stylar proteins of Japanese pear (Pyrus serotina Rehd.) were analyzed by two-dimensional gel electrophoresis, and a 32-kDa protein with an isoelectric point of 4.8 was found to be a major component in the style. The 32-kDa protein was a soluble glycoprotein which reacted with concanavalin A. The 32-kDa protein specifically accumulated in the style in a developmentally regulated manner, but was not detected in the other floral organs and leaves. An oligonucleotide representing the N-terminal amino acid sequence of the 32-kDa protein was used to amplify a cDNA fragment by polymerase chain reaction (PCR). The generated PCR product was used to screen a style cDNA library. The selected cDNA clone encoded 244 amino acid residues containing the N-terminal sequence of the 32-kDa protein. The N-terminus of the protein was preceded by putative signal peptide of 22 amino acid residues. The 32-kDa protein showed significant homology with the thaumatin/PR5-like proteins, and was named PsTL1 (Pyrus serotina thaumatin-like protein 1). The possible biological role of PsTL1 in the styles is discussed.
Kihara Institute for Biological Research, Yokohama City University, Japan. sassa@yokohama-cu.ac.jp
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D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D018744:DNA, Plant; D005638:Fruit / Q000235:genetics / Q000378:metabolism; D006023:Glycoproteins / Q000737:chemistry / Q000235:genetics*; D006031:Glycosylation; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics*; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D013549:Sweetening Agents
D018076:DNA, Complementary; D018744:DNA, Plant; D006023:Glycoproteins; D010940:Plant Proteins; D013549:Sweetening Agents; C113929:TL1 protein, Pyrus pyrifolia; C003427:thaumatin protein, plant