Metabolic and Physiological Changes in the Roots of Two Oat Cultivars in Response to Complex Saline-Alkali Stress

Abstract

Saline-alkali stress is a major abiotic stress factor in agricultural productivity. Oat (Avena sativa L.) is a saline-alkali tolerant crop species. However, molecular mechanisms of saline-alkali tolerance in oats remain unclear. To understand the physiological and molecular mechanisms underlying seedling saline-alkali tolerance in oats, the phenotypic and metabolic responses of two oat cultivars, Baiyan7 (BY, tolerant cultivar) and Yizhangyan4 (YZY, sensitive cultivar), were characterized under saline-alkali stress conditions. Compared with YZY, BY showed better adaptability to saline-alkali stress. A total of 151 and 96 differential metabolites induced by saline-alkali stress were identified in roots of BY and YZY, respectively. More detailed analyses indicated that enhancements of energy metabolism and accumulations of organic acids were the active strategies of oat roots, in response to complex saline-alkali stress. The BY utilized sugars via sugar consumption more effectively, while amino acids strengthened metabolism and upregulated lignin and might be the positive responses of BY roots to saline-alkali stress, which led to a higher osmotic adjustment of solute concentrations and cell growth. The YZY mainly used soluble sugars and flavonoids combined with sugars to form glycosides, as osmotic regulatory substances or antioxidant substances, to cope with saline-alkali stress. The analyses of different metabolites of roots of tolerant and sensitive cultivars provided an important theoretical basis for understanding the mechanisms of saline-alkali tolerance and increased our knowledge of plant metabolism regulation under stress. Meanwhile, some related metabolites, such as proline, betaine, and p-coumaryl alcohol, can also be used as candidates for screening saline-alkali tolerant oat cultivars.

Comprehensive physiological, transcriptomic, and metabolomic analysis of the response of Panicum miliaceum L. roots to alkaline stress

“…However, the relative content of the above metabolites in the alkaline stress group was less than that in the control group, indicating that root cells are still affected by alkaline stress damage and affect growth. Results similar to previous report where phenylalanine accumulation was downregulated in oat roots by saline‐alkali stress, suggesting that phenylpropanoid biosynthesis was partially inhibited (Gao et al, 2022).…”

Rhizophagus irregularis and biochar can synergistically improve the physiological characteristics of saline‐alkali resistance of switchgrass

“…Soil salinity and alkalinity are the most important abiotic stress factors affecting plant health and growth. The roots are the primary organs responsible for nutrient and water absorption from the soil and are more sensitive to salt and alkali stress compared to other plant tissues (Gao et al, 2022). Saline‐alkali stress may adversely affect the establishment of the symbiotic relationship between AMF and plants and lead to a decrease in the number of endospores, mycelium, vesicles, and arbuscles in plant roots (Qin et al, 2021).…”

Differences in Organic Solute and Metabolites of Leymus chinensis in Response to Different Intensities of Salt and Alkali Stress

“…Because metabolites are the end products of biological systems, changes in metabolic levels in organisms are expected to be connected with phenotypes. Numerous Plants 2023, 12,1916 2 of 15 studies have confirmed that some metabolites, such as proline, betaine, organic acids, soluble sugars, nitrogen compounds, and polyols, are beneficial in improving plant salt tolerance [3,6,7]. Meanwhile, plants also need to accumulate specific metabolites to balance intracellular pH in addition to the metabolites listed above under alkali stress.…”

“…Meanwhile, plants also need to accumulate specific metabolites to balance intracellular pH in addition to the metabolites listed above under alkali stress. Among these, organic acid accumulation is a form of plant adaptation to high pH; multiple studies have demonstrated that an increase in organic acid concentration improved plants' alkali stress resistance [6,7]. Metabolite accumulation involves the activation of metabolic processes, and plants enhance metabolite accumulation by activating metabolic pathways, hence strengthening stress tolerance.…”

“…Metabolite accumulation involves the activation of metabolic processes, and plants enhance metabolite accumulation by activating metabolic pathways, hence strengthening stress tolerance. A variety of studies have revealed that stimulating the synthesis pathways of the osmotic solutes mentioned above, such as amino acids, betaine, and soluble sugars, is critical for improving plant salt tolerance [2,[6][7][8]. Energy supply pathways, such as β-oxidation, glycolysis, and the TCA cycle are typically important for enhancing plant alkali tolerance [9][10][11].…”