Metabolic and Physiological Regulation of Aspartic Acid-Mediated Enhancement of Heat Stress Tolerance in Perennial Ryegrass

Abstract

Aspartate is the most critical amino acid in the aspartate metabolic pathway, which is associated with multiple metabolic pathways, such as protein synthesis, nucleotide metabolism, TCA cycle, glycolysis, and hormone biosynthesis. Aspartate also plays an important role in plant resistance to abiotic stress, such as cold stress, drought stress, salt stress or heavy metal stress. This study found that the chlorophyll content and antioxidant active enzyme content (SOD, CAT, POD and APX) of perennial ryegrass treated with 2 mM aspartate were significantly higher than those treated with water under heat stress. The electrolyte leakage rate, MDA content and peroxide levels (O2− and H2O2) of perennial ryegrass treated with aspartate were significantly lower than those of perennial ryegrass treated with water, indicating that exogenous aspartate increases the content of chlorophyll, maintain the integrity of cell membrane system, and enhances SOD-CAT antioxidant pathway to eliminate the oxidative damage caused by ROS in perennial ryegrass under heat stress. Furthermore, exogenous aspartate could enhance the TCA cycle, the metabolism of the amino acids related to the TCA cycle, and pyrimidine metabolism to enhance the heat tolerance of perennial ryegrass.

Exogenous aspartic acid alleviates salt stress-induced decline in growth by enhancing antioxidants and compatible solutes while reducing reactive oxygen species in wheat

“…Our study found that foliar application of amino acids (Asp) can affect plant vegetative development and improve plant growth under salt stress. Moreover, aspartic acid enhanced the heat tolerance of perennial ryegrass ( Lei et al., 2022 ).…”

“…Under salt stress, Asp accumulates with other amino acids like proline, which is linked to its involvement in osmotic adjustment and membrane stability ( Hayat et al., 2012 ). Although the underlying metabolic pathways are unknown, exogenous application of Asp can improve plant tolerance to salt ( Zhang et al., 2020 ), heat stress ( Lei et al., 2022 ), and cadmium toxicity ( Rizwan et al., 2017b ) based on plant growth and physiological responses. In plants, vascular tissues are responsible for transporting wide-ranging types of amino acids with varying concentrations.…”

Reprogramming of Plant Central Metabolism in Response to Abiotic Stresses: A Metabolomics View

“…The plant metabolic network has to be reprogrammed under stresses so that essential metabolic homeostasis is maintained and protective metabolites are produced to enhance stress tolerance [ 21 ]. Exogenous application of metabolites, such as amino acids, sugars, and specialized metabolites (secondary metabolites), has proven to effectively increase stress tolerance in various crop plants [ 17 , 22 , 23 , 24 ]. Evolving metabolomics approaches have shed light on the regulation of central metabolism and specialized metabolism under abiotic stresses [ 1 , 25 , 26 , 27 , 28 , 29 ].…”

Proliferation and Metabolic Profiling of Cynanchum wilfordii Adventitious Roots Using Explants from Different Cultivation Methods

“…However, other amino acids, including valine and β-alanine, were largely accumulated in ARs from ECH. This was because amino acids in the aspartate–glutamate pathway are commonly used as nitrogen carriers and are converted into other amino acids, such as valine, threonine, and isoleucine . We speculated that the large amount of amino acids in the aspartate–glutamate pathway was consumed for adaptation to the heap-cultivation conditions, resulting in the utilization of these amino acids for the synthesis of other amino acids, such as valine and β-alanine.…”