Optimizing raffinose family oligosaccharides content in plants: A tightrope walk

Abstract

Plants synthesize various compounds for their growth, metabolism, and stress mitigation, and one such group of compounds is the raffinose family of oligosaccharides (RFOs). RFOs are non-reducing oligosaccharides having galactose residues attached to a sucrose moiety. They act as carbohydrate reserves in plants, assisting in seed germination, desiccation tolerance, and biotic/abiotic stress tolerance. Although legumes are among the richest sources of dietary proteins, the direct consumption of legumes is hindered by an excess of RFOs in the edible parts of the plant, which causes flatulence in humans and monogastric animals. These opposing characteristics make RFOs manipulation a complicated tradeoff. An in-depth knowledge of the chemical composition, distribution pattern, tissue mobilization, and metabolism is required to optimize the levels of RFOs. The most recent developments in our understanding of RFOs distribution, physiological function, genetic regulation of their biosynthesis, transport, and degradation in food crops have been covered in this review. Additionally, we have suggested a few strategies that can sustainably reduce RFOs in order to solve the flatulence issue in animals. The comprehensive information in this review can be a tool for researchers to precisely control the level of RFOs in crops and create low antinutrient, nutritious food with wider consumer acceptability.

Uncovering the wide protective responses in Coffea spp. leaves to single and superimposed exposure of warming and severe water deficit

“…Belonging to the RFOs, the trisaccharide raffinose is also an important stress-responsive sugar. The accumulation and increased expression of genes associated with its biosynthetic pathway have been shown to play a pivotal importance to plant-acquired tolerance to various biotic/abiotic stresses, namely to desiccation, cold, salinity, drought, osmotic and oxidative stress ( Li et al., 2020 ; Yan et al., 2022 ; Sanyal et al., 2023 ). Here, raffinose content was unresponsive to drought in both cultivars, but greatly rose in Icatu plants at the two highest temperatures, as also reported in C. arabica cv.…”

Physiological and transcriptomic characterization of cold acclimation in endodormant grapevine under different temperature regimes

“…Cell wall invertase genes were reported to be upregulated under cold stress in Catharanthus roseus 87 . Raffinose synthase and stachyose synthase catalyze key reactions of the biosynthesis of raffinose and stachyose, two raffinose family oligosaccharides whose accumulation are correlated to the enhancement of low temperature tolerance in various plant species, including grapevine [88][89][90][91][92] . In the phenylpropanoid biosynthesis pathway, low temperature responsive genes include a gene encoding cinnamoyl-CoA reductase (Vitvi02g00717), one gene encoding cinnamoyl alcohol dehydrogenase (Vitvi13g02156), one gene encoding resveratrol synthesis (Vitvi16g01474) and four genes encoding stilbene synthase (Vitvi16g00988, Vitvi16g01470, Vitvi16g01474 and Vitvi16g01484) (Figure S6A).…”

Plant Heterotrophic Cultures: No Food, No Growth

“…These are oligosaccharides which, like sucrose, include glucose and fructose residues with galactose residue addition. Raffinose plays an important role in various processes such as stress resistance and seed germination [ 111 , 112 ]. Raffinose-like sugars are considered as an important transport form of carbon for some plants, in particular from the families Cucurbitaceae and Scrophulariaceae [ 88 , 113 ].…”

“…For raffinose, the capacity to support growth at a level close to sucrose was shown in an analysis of heterotrophic tobacco cell culture growth [ 117 ], and of cell cultures obtained from some other plants such as wild carrot [ 118 ] and sugarcane [ 119 ]. RFO entry into the metabolism starts from its cleavage to sucrose and galactose, or other hexoses [ 82 , 111 ].…”