RESUMEN
Current data on the diversity of plant lectins and their functional importance for plants, caused primarily by their capacity to link carbohydrate ligands specifically and convertibly, are reviewed. For instance, the role of plant lectins in the recognition of alien organisms and in the adaptation of plants to various stress-induced effects is discussed. In addition to centres of specific affinity to carbohydrates, plant lectins are characterized by the presence of sites responsible for hydrophobic interactions with non-carbohydrate molecules. These sites link to plant hormones, proteins, and other metabolites, thus participating in the regulation of metabolic processes controlling growth, development, and differentiation in plants. The structure and biological properties of ribosome-inactivating proteins having and not having lectin activity are discussed, as well as their role in plant protection from pests and pathogens. Current data on the assumed functions of the independent groups of plant lectins with specific endogenic role are given. These include chitin-specific lectins synthesized in phloem, which are capable of forming protein-protein and RNA-protein complexes and translocating via vessels, which thus play their specific intra- or intercellular interactions, processes of growth, development, and protection of plants. Other groups of plant lectins, induced by jasmonate, such as Nictaba (Nicotiana tabaccum agglutinin), and cereal lectins related to jacalin, which are localised in the cytoplasm and nucleus, probably play regulatory role in the formation of stress response in plants. The structure and currently discussed functions of wheat germ agglutinin, a typical representative of cereal lectins, are analysed in detail.
Asunto(s)
Lectinas de Plantas/fisiología , Plantas/metabolismo , Aglutininas del Germen de Trigo/metabolismo , Lectinas de Plantas/clasificación , Lectinas de Plantas/metabolismo , Proteínas de Plantas/metabolismo , Plantas/genética , ARN de Planta/metabolismoAsunto(s)
Ácido Abscísico/metabolismo , Regulación de la Expresión Génica de las Plantas , Proteínas de Plantas/biosíntesis , Proteínas de Plantas/genética , Triticum/metabolismo , Frío , Genes de Plantas , Hojas de la Planta/metabolismo , Fenómenos Fisiológicos de las Plantas , Proteínas de Plantas/química , Temperatura , Factores de TiempoRESUMEN
Effects of 20 nM wheat germ agglutinin (WGA) on relative growth rate, mitotic index (MI) and the cell area in the root extension zone were investigated in seedling of Triticum aestivum L. under the influence of 2% NaCl. It was elucidated that pretreatment of wheat seedling with WGA prevented a salinity induced inhibition of root cell growth, and accelerated the restoration of cell growth after stress removal. The protective WGA effect on root cell growth may be due, presumably, to reorganization of phytohormone balance caused by WGA treatment, which could lead to accumulation of LAA and decrease in the ABA level.
Asunto(s)
Reguladores del Crecimiento de las Plantas/farmacología , Cloruro de Sodio/farmacología , Triticum/efectos de los fármacos , Aglutininas del Germen de Trigo/farmacología , Raíces de Plantas/efectos de los fármacos , Raíces de Plantas/crecimiento & desarrollo , Plantones/efectos de los fármacos , Plantones/crecimiento & desarrollo , Cloruro de Sodio/antagonistas & inhibidores , Triticum/crecimiento & desarrolloRESUMEN
A study was made of cell division activity and hormonal status in roots of 4 day old wheat seedling treated with wheat germ agglutinin (WGA). The revealed stimulating effect of WGA on mitotic index (MI) and cell area in root extension zone was specific for this lectin, because gliadin, taken as a control protein, caused no changes in growth parameters. Phytolectins (phytohemagglutinin and concanavalin A) possessing properties of mitogens rendered no such essential influence on cell growth of wheat. Immunoassay has shown that WGA-treatment leads to accumulation of auxins and cytokinins in roots. This suggest participation of WGA in regulation of MI of meristem cells in roots of seedlings during their interaction with phytohormones.