Plant lectins

Plant lectins are being studied for over a century. Until a decade ago, most information was obtained from biochemical, molecular, and structural studies of a reasonably high but still limited number of abundant lectins from seeds and vegetative storage organs. Though the results of these studies are still valid, the recent progress made in several areas of plant lectin research urge to profoundly revise the prevailing concepts. This contribution aims to give a comprehensive overview of the occurrence, taxonomic distribution, molecular evolution, and physiological role of plant lectins with the emphasis on relevant novel developments. The overview comprises a description of the 12 different carbohydrate binding domains and annex lectin families that hitherto have been identified in plants. For each lectin family, a fairly detailed summary is given of the biochemical properties, taxonomical distribution, and evolutionary origin. Novel insights in some specific aspects of plant lectins like their biosynthesis and topogenesis, carbohydrate binding specificity, and regulation of expression are discussed. The last major section deals with an updated critical discussion of the physiological role of plant lectins with an emphasis on specific functions within the plant cell. Finally, the concept of "lectinome" is introduced