Metabolic Responses of Two Contrasting Lentil Genotypes to PEG-Induced Drought Stress

Abstract

Among abiotic stresses, drought is undoubtedly one of the most severe environmental factors for a wide range of major crops, leading to considerable yield and economic losses. The adverse effects in crop yield reflect the result of a series of morphological and physiological changes but also changes in signaling pathways, transcriptional and post-transcriptional regulation of stress-responsive genes, and metabolic adaptations. Despite the exhausting studies elucidating plants’ metabolic response to drought, there is a knowledge gap in the biochemical mechanisms governing drought tolerance in lentil (Lens culinaris Medik.). The present study aimed to determine the fluctuations of the metabolite profiles of lentil genotypes with contrasting drought tolerance to discover possible biomarkers for screening tolerant genotypes at early growth stages. Lentil seedlings were subjected to osmotic drought stress, induced by polyethylene glycol, at two stress levels (2.5% and 5.0% PEG-6000) for a period of 20 days, while untreated plants were also included as controls. GC/ΕΙ/MS-mediated metabolic profiling was employed to monitor changes in response to osmotic drought stress. The data was subjected to OPLS-DA and OPLS-HCA for the discrimination between treatments and the discovery of trends and corresponding biomarkers. In total, the analysis yielded 150 metabolite features with highly reproducible patterns, of which the vast majority belonged to carbohydrates, carboxylic acids, and amino acids. Overall, findings highlight the differential accumulation of a series of compounds, and more importantly, the variable accumulation of certain metabolites, namely D-fructose, α,α-trehalose, myo-inositol, and L-tryptophan, in the contrasting genotypes, indicating that the adaptive metabolic responses to osmotic drought stress operate under strong genotypic dependency in lentil. Research findings provide insights into various aspects of lentil’s metabolism under drought and further offer the possibility of applying such knowledge towards effectively screening for drought-tolerant lentil germplasm at early growth stages.

Comparative Analysis of Untargeted Metabolomics in Tolerant and Sensitive Genotypes of Common Bean (Phaseolus vulgaris L.) Seeds Exposed to Terminal Drought Stress

“…In lentil ( Lens culinaris Medik. ), significant changes in xylose accumulation were observed during osmotic drought stress [ 41 ].…”

Metabolomics for Crop Breeding: General Considerations

“…L-asparagine responded to stress in tolerant Elpida stronger than in susceptible Flip03-24L (20 fold vs. 7 fold). Carboxylic acid raised in stress with a stronger effect in the tolerant Elpida: seven-ten-fold in Elpida vs. five-six-fold in Flip03-24L for 2-ketoglutaric acid, five-fold vs. no change for malonic acid and four-fold vs. two-three-fold for citric acid [104].…”

Novel Chemical and Biological Insights of Inositol Derivatives in Mediterranean Plants

“…Arachis hypogea D-pinitol, D-chiro-inositol, myo-inositol [41] Ceratonia silique D-pinitol, allo-inositol, D-chiro-inositol, bornesitol, scyllo-inositol, myo-inositol [41,43] Cicer arietinum D-pinitol, D-chiro-inositol, myo-inositol, galactosyl-inositol, galactosyl-pinitol, ciceritol [43,44] Erythrina edulis D-chiro-inositol, myo-inositol [44] Fagopyrum esculentum D-chiro-inositol, myo-inositol, galactosyl-inositol, fagopyritol [43] Glycine max D-pinitol, D-chiro-inositol, myo-inositol, fagopyritol, galactosyl-pinitol [43,44,54] Glycyrrhiza glabra D-pinitol [52] Latirus sativus bornesitol, myo-inositol, galactosyl-inositol [43] Lens culinaris D-pinitol, D-chiro-inositol, bornesitol, myo-inositol, galactosyl-inositol, galactosyl-pinitol, ciceritol [43,55] Lupinus perennis D-pinitol, allo-inositol, D-chiro-inositol, bornesitol, myo-inositol [41] Medicago sativa D-pinitol, D-chiro-inositol, ononitol, scyllo-inositol, myo-inositol [41,47] Phaseolus polyanthus myo-inositol [44] Phaseolus vilgaris myo-inositol [44,46] Pisum sativum myo-inositol [44] Trigonella foenum-graecum D-pinitol, D-chiro-inositol, bornesitol, myo-inositol [41] Vicia faba myo-inositol [44] Vicia sativa myo-inostol [44] Vigna unaniculata ononitol, myo-inositol, galactosyl-inositol, galactosyl-ononitol [43][44][45] Hydrophyllaceae Phacella tanacetifolia A special mention as source of inositols deserves a plant-animal hybrid product, that is, bee honey, where quercitol (1,3,4/2,5-cyclohexanepentol), D-pinitol, 1-O-methylmuco-inositol and muco-inositol have been identified for the first time only in 2004 by Sanz et al [57]. In their work, 28 different honeys were analyzed finding that these compounds were present only in a limited number of samples, likely those collected by bees from wild plants.…”

“…Their analyses revealed, for the first time in these species, the presence of chiro -inositol in addition to myo -inositol; furthermore, significant variations in chiro -inositol level as salinity increased suggested that this compound contributes to osmotic adjustment in the stressed plants, and that chiro -inositol response might be a physiological process for Limonium salt adaptation. Finally, in a very recent study, Foti et al [ 55 ] investigated the metabolic response of lentil ( Lens culinaris Medik, Fabaceae) when subjected to osmotic drought stress induced by PEG (polyethylene glycol). The authors found that not only a number of compounds, including myo -inositol, undergo differential accumulation, but also that the adaptive metabolic responses to osmotic drought stress operate under strong genetic control.…”