Recognition reactions between soybean lectin and rhizobial lipopolysaccharides in the infection process

• Main Authors: Song,Shuh-Chyung, 宋樹群
• Other Authors: Lin,Liang-Ping
• Format: Others
• Language: zh-TW
• Published: 1993
• Online Access: http://ndltd.ncl.edu.tw/handle/41623088071280776551

博士 === 國立臺灣大學 === 農業化學系 === 81 === Rhizobia can infect leguminous plants to form symbiotic no- dules in which nitrogen gas is transferred to ammonium nitrogen, a natural nutrition to host plant. In this symbiotic process, there is specific infection existing between Rhizobium and le- gume host. Some researchers have suggested a lectin-polysaccha- ride recognition hypothesis, which could interpret this specific symbiosis. However, there are many results contradictory to this hypothesis recently. Rhizobia, infecting soybean, can be classi- fied to types. One is R. fredii, the fast-growing type, and the other B. japonicum, slow-growing type. Whether or not a relation- ship that exist between soybean lectin and polysaccharides of these Rhizobium species. In these experiments, we tried to clari- fy the hypothesis of soybean as common host. Firstly, we isolated and purified soybean lectin. This soy- bean lectin was analyzed by gel permeation chromatography and SDS-PAGE analysis. The rhizobia which exopolysaccharide was re- moved could bind with FITC-labeled soybean lectin. Results showed every Rhizobium strain could bind with soybean lectin. Exo- polysaccharide removed rhizobia were reacted with soybean lectin, then, bound with anti-soybean lectin antisera, finally stained with immunogold. We obtained the same results through TEM obser- vation. Rhizobial lipopolysaccharides were purified through gel per- meation chromatography. We can distinguish them by different strains. The purified lipopolysaccharides were analyzed with SDS- PAGE. These lipopolysaccharides were analyzed by GLC after being hydrolyzed, reduced, and acetylated. Major hexose compositions were glucose, galactose and mannose. However, B. japonicum USDA 110 was devoid of galactose and bound with soybean lectin. There- fore, it was shown that our results did not support lectin-poly- saccharide recognition hypothsis.