Abiotic Stress in Crop Species: Improving Tolerance by Applying Plant Metabolites

Abstract

Reductions in crop yields brought about by abiotic stress are expected to increase as climate change, and other factors, generate harsher environmental conditions in regions traditionally used for cultivation. Although breeding and genetically modified and edited organisms have generated many varieties with greater abiotic stress tolerance, their practical use depends on lengthy processes, such as biological cycles and legal aspects. On the other hand, a non-genetic approach to improve crop yield in stress conditions involves the exogenous application of natural compounds, including plant metabolites. In this review, we examine the recent literature related to the application of different natural primary (proline, l-tryptophan, glutathione, and citric acid) and secondary (polyols, ascorbic acid, lipoic acid, glycine betaine, α-tocopherol, and melatonin) plant metabolites in improving tolerance to abiotic stress. We focus on drought, saline, heavy metal, and temperature as environmental parameters that are forecast to become more extreme or frequent as the climate continues to alter. The benefits of such applications are often evaluated by measuring their effects on metabolic, biochemical, and morphological parameters in a variety of crop plants, which usually result in improved yields when applied in greenhouse conditions or in the field. As this strategy has proven to be an effective way to raise plant tolerance to abiotic stress, we also discuss the prospect of its widespread implementation in the short term.

Salt and Drought Stress Responses in Cultivated Beets (Beta vulgaris L.) and Wild Beet (Beta maritima L.)

“…Interestingly, up-regulation of proline was observed not only under drought stress but also after rehydration [ 98 ]. In plants, exogenous proline improves root surface to handle water deficit and nutrient deficiency [ 99 ]. Consistently, recent reports ascertained that the exogenous application of proline can minimize drought-induced damages in sugar beet [ 9 , 11 , 54 ].…”

γ-Aminobutyrate (GABA) Regulated Plant Defense: Mechanisms and Opportunities

“…There is considerable interest in improving stress tolerance using breeding and genetic engineering approaches, and exogenous application of natural compounds, including primary and secondary metabolites [ 4 ]. γ-Aminobutyrate (GABA) is a ubiquitous four-carbon, non-proteinogenic amino acid, which functions as both metabolite and signal in response to abiotic and biotic stresses [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ].…”

“…These changing climatic conditions could facilitate the geographic expansion and aggressiveness of phytopathogens and modify host susceptibility [3]. Therefore, it is imperative to develop crop production systems that are more sustainable under stress conditions [4].…”

Comparison of Drought and Heat Resistance Strategies among Six Populations of Solanum chilense and Two Cultivars of Solanum lycopersicum

“…Abiotic stresses caused by environmental factors can affect the growth and development of crops with consequent decreases of crop yields and quality [33,34]. In cultivated tomato, abiotic stress causes about 70% yield loss, depending upon the plant stage and duration of the stress [35].…”