Medicago sativa and Medicago truncatula Show Contrasting Root Metabolic Responses to Drought

Abstract

Drought is an environmental stressor that affects crop yield worldwide. Understanding plant physiological responses to stress conditions is needed to secure food in future climate conditions. In this study, we applied a combination of plant physiology and metabolomic techniques to understand plant responses to progressive water deficit focusing on the root system. We chose two legume plants with contrasting tolerance to drought, the widely cultivated alfalfa Medicago sativa (Ms) and the model legume Medicago truncatula (Mt) for comparative analysis. Ms taproot (tapR) and Mt fibrous root (fibR) biomass increased during drought, while a progressive decline in water content was observed in both species. Metabolomic analysis allowed the identification of key metabolites in the different tissues tested. Under drought, carbohydrates, abscisic acid, and proline predominantly accumulated in leaves and tapRs, whereas flavonoids increased in fibRs in both species. Raffinose-family related metabolites accumulated during drought. Along with an accumulation of root sucrose in plants subjected to drought, both species showed a decrease in sucrose synthase (SUS) activity related to a reduction in the transcript level of SUS1, the main SUS gene. This study highlights the relevance of root carbon metabolism during drought conditions and provides evidence on the specific accumulation of metabolites throughout the root system.

Evaluation of the Morpho-Physiological, Biochemical and Molecular Responses of Contrasting Medicago truncatula Lines under Water Deficit Stress

“…This increase has been described as a common behavior in drought-stressed plants due to their role in osmoregulation, amongst others [4]. A recent study of Echeverria et al [50] focused on soluble sugars in relation to their role in the protection against water deficit stress. Free proline is well-known to increase in response to water deficit in plants, and recent evidence from metabolite measurements shows that water deficit leads to the elevation of proline in Medicago sativa and Medicago truncatula leaf and root tissue.…”

Supercritical CO2-Based Extraction and Detection of Phenolic Compounds and Saponins from the Leaves of Three Medicago varia Mart. Varieties by Tandem Mass Spectrometry

“…These numbers of compounds in respective groups indicate that M. varia extracts are rich in flavonoids. The highest numbers of chemical compounds from other groups were recorded for polysaccharides (8) and saponins (11).…”

“…GC-MS analysis of M. sativa seeds revealed their enrichment in crude protein (33.79%), crude oil (8.11%), squalene, Processes 2024, 12, 1041 2 of 25 hexadecanoic acid methyl ester, n-hexadecanoic acid, 9,12-octadecadienoic acid methyl ester, 9-octadecenamide and vitamin E. Moreover, Medicago sativa seed inclusion in the diet is recommended to normalize serum cholesterol levels in type II hyperlipoproteinemia patients [4][5][6]. Additionally, there are several interesting scientific studies showing the presence of simple phenolic compounds in Medicago [7,8]. These compounds have a range of biological activities, including anti-inflammatory, antioxidant, phytoestrogenic and anticarcinogenic abilities, as well as their interactions with intracellular signaling pathways and regulation of cell survival.…”

Single-cell transcriptome sequencing reveals alfalfa root tip developmental landscape

“…As a key plate in the development of leguminous root tip stem cells, SHC-SCR can undergo cortical division, which can be activated by rhizobial signals to form nodules [12]. Alfalfa has thick root tissues, large root and soil contact area, and high lignin content, responsible for its high protein content and strong adaptability to drought and saline-alkali environments [13].…”