Heat-shock proteins and cross-tolerance in plants

Environmental stresses dramatically affect plant survival and productivity. Because plants are immobile, presumably different strategies are required for protection against transient stresses. Under stress, plants synthesize specific proteins, and their accumulation has a role in protecting the tissue from possible damage. An increasing number of studies show the existence of cross-tolerance in plants: Exposure of tissue to moderate stress conditions often induces resistance to other stresses. Many varied mechanisms explaining the phenomenon of cross-tolerance have been proposed, and they often, but not always, suggest that specific proteins are induced by one kind of stress and are involved in the protection against other kinds. Although various cross-protections have been demonstrated in a number of plants, a common mechanism has not been found. This review discusses heat-shock proteins and their possible roles in protecting the plant under heat and other stresses.