Isolation of a plant glycoprotein involved with control of intercellular recognition [Cabbage]

• Published in: Plant physiology (Bethesda) 1981-02, Vol.67 (2), p.270-277
• Main Authors: Ferrari, T E, Bruns, D, Wallace, D H
• Format: Article
• Language: English
• Subjects: Amino acids; Antigens; Brassica oleracea; Chromatography; Gels; Genotypes; Glycoproteins; Molecules; Plant antigens; Pollen; Protein synthesis; purification
• ISSN: 0032-0889; 1532-2548
• DOI: 10.1104/pp.67.2.270

A recognition molecule was isolated from stigmas of S-allele genotype $\text{S}_{2}\text{S}_{2}$ of Brassica oleracea var. capitata L. After Sephadex chromatography, it eluted as a single symmetrical peak during diethylaminoethane-cellulose chromatography. A high degree of purity was affirmed by: sedimentation as a single peak during ultracentrifugation through 5 to 20% sucrose gradients; elution as a single peak from Sephadex G-100; visualization as a single band which stains with Coomassie blue and periodic acid Schiff reagent after electrophoresis on polyacrylamide gels. Other criteria supporting the conclusion that it is a glycoprotein are: (a) the highly purified preparation is anthrone-positive and has a Lowry protein to anthronepositive carbohydrate ratio of 1.3; (b) the preparation contains arabinose, galactose, glucose, and mannose, although it is not precipitated by concanavalin A; (c) the immunological properties of the molecule are lost following protease treatment, and it has a molecular weight of 90,000 by Sephadex gel-filtration analysis and 54,500 by velocity sedimentation analysis. In vitro pretreatment of $\text{S}_{2}\text{S}_{2}$ pollen with the post-diethylaminoethanepurified S2 glycoprotein prevented the $\text{S}_{2}\text{S}_{2}$ pollen from germinating on three classes of compatible stigmas: (a) mature stigmas of genotypes $\text{S}_{3}\text{S}_{3}$ and $\text{S}_{8}\text{S}_{8}$, which are non-self genotypes; (b) immature stigmas of genotype $\text{S}_{2}\text{S}_{2}$, where incompatibility is not expressed; and (c) mature stigmas with a recessive S2 allele. Pretreatment of $\text{S}_{3}\text{S}_{3}$ and $\text{S}_{8}\text{S}_{8}$ pollen with the S2 glycoprotein did not interfere with their germination.