Insights on Fructans and Resistance of Plants to Drought Stress

Abstract

Drought, one of the major abiotic stresses affecting plants, is characterized by a decrease of water availability, resulting in a decrease of the water potential (Ψ) of the cells. One of the strategies of plants in resisting to this low Ψ and related stresses is regulating their water-plant relation and the interplay between Ψsolutes and the turgor pressure (Ψp). This regulation avoids the dehydration induced by low Ψ and is resulting from the accumulation of specific molecules which induce higher tolerance to water deficit and also other mechanisms that prevent or repair cell damages. In plants, fructans, the non-structural carbohydrates (NSC), have other physiological functions than carbon reserve. Among these roles, fructans have been implicated in protecting plants against water deficit caused by drought. As an efficient strategy to survive to this abiotic stress, plants synthesize fructans in response to osmotic pressure in order to osmoregulate the cellular flux, therefore, protecting the membrane damage and maintaining Ψp. Although different studies have been conducted to elucidate the mechanisms behind this strategy, still the concept itself is not well-understood and many points remain unclear and need to be elucidated in order to understand the causal relation between water deficit and fructans accumulation during water scarcity. This understanding will be a key tool in developing strategies to enhance crop tolerance to stressful dry conditions, particularly under the changing climate prediction. This review aims to give new insights on the roles of fructans in the response and resistance of plants to water deficit and their fate under this severe environmental condition.

Mechanisms of Kale (Brassica oleracea var. acephala) Tolerance to Individual and Combined Stresses of Drought and Elevated Temperature

“…On the other hand, fructans content was significantly increased in 404 under all stress conditions. Fructans are the non-structural carbohydrates, possessing other physiological functions than carbon reserve [ 42 ]. Fructans have been reported to have a protecting role in plants against water deficit caused by drought and osmotic stress.…”

Garlic Ecotypes Utilise Different Morphological, Physiological and Biochemical Mechanisms to Cope with Drought Stress

“…Increased accumulation of inulin could protect cells from dehydration during drought [66]. The protective action of fructans can be attributed to their ability to insert themselves between the lipids of the membrane [66], and thus stabilize it during drought [67]. Vereyken et al [68] demonstrated that inulin-type fructans protect membranes.…”

Single and co-inoculum of endophytic bacteria promote growth and yield of Jerusalem artichoke through upregulation of plant genes under drought stress

“…B. velezensis 5.18 strongly promoted root development (length, diameter, surface, volume), leading to high biomass (root and shoot weight). It is possible that this strain possessed levansucrase [21] and produced fructooligosaccharide to prolong fructans which are involved in osmotic adjustment for plant growth and tolerance [31]. The osmoprotectants are sugars (e.g., sucrose), glycine betaine, organic acids (e.g., malate), inorganic ions (e.g., calcium), and proline which protect proteins, organelles, membranes, and genetic materials against stress, including balance of osmotic pressure [32].…”