Influence of

Abstract

Azospirillum spp. are plant-growth-promoting rhizobacteria. The surface lectins of A. brasilense strain Sp7 and A. baldaniorum strain Sp245 can attach to specific carbohydrates, and ensure the binding of the bacteria to the root surface. We investigated possible effects of A. brasilense Sp7 and A. baldaniorum Sp245 lectins on the activities of antioxidant enzymes and on the content of low-molecular-weight antioxidants in the roots of 4-day-old wheat seedlings. The roots were exposed to a number of simulated abiotic stresses: hypothermic, hyperthermic, drought, and salinity stresses. Under all stresses, both lectins increased peroxidase and superoxide dismutase activities and decreased catalase activity. The lectins differed in the intensity of induction of changes in the amounts of the low-molecular-weight antioxidants in wheat roots. They also differed in functional activity owing to their different carbohydrate specificities and structures. The data suggest broader possibilities of lectins in terms of the effect on the metabolism of host plants, and they permit adjustments to be made to the current understanding of the mechanisms that control the associative interactions between plants and bacteria.