Metabolic Fingerprinting to Assess the Impact of Salinity on Carotenoid Content in Developing Tomato Fruits

Abstract

As the presence of health-promoting substances has become a significant aspect of tomato fruit appreciation, this study investigated nutrient solution salinity as a tool to enhance carotenoid accumulation in cherry tomato fruit (Solanum lycopersicum L. cv. Juanita). Hereby, a key objective was to uncover the underlying mechanisms of carotenoid metabolism, moving away from typical black box research strategies. To this end, a greenhouse experiment with five salinity treatments (ranging from 2.0 to 5.0 decisiemens (dS) m−1) was carried out and a metabolomic fingerprinting approach was applied to obtain valuable insights on the complicated interactions between salinity treatments, environmental conditions, and the plant’s genetic background. Hereby, several hundreds of metabolites were attributed a role in the plant’s salinity response (at the fruit level), whereby the overall impact turned out to be highly depending on the developmental stage. In addition, 46 of these metabolites embraced a dual significance as they were ascribed a prominent role in carotenoid metabolism as well. Based on the specific mediating actions of the retained metabolites, it could be determined that altered salinity had only marginal potential to enhance carotenoid accumulation in the concerned tomato fruit cultivar. This study invigorates the usefulness of metabolomics in modern agriculture, for instance in modeling tomato fruit quality. Moreover, the metabolome changes that were caused by the different salinity levels may enclose valuable information towards other salinity-related plant processes as well.

Salinity impairs photosynthetic capacity and enhances carotenoid-related gene expression and biosynthesis in tomato (Solanum lycopersicumL. cv. Micro-Tom)

“…These authors proposed a salinity-induced stimulation of the accumulation of starch during early fruit development, enhancing soluble solids content in ripe fruits (Yin et al, 2010). Other independent studies have shown that higher dry matter, sugar, and organic acid concentrations can be observed upon increasing salinity treatments (Wu & Kubota, 2008;Van Meulebroek et al, 2016). Also, there may be a correlation of the aforementioned effects on tomato fruits, the decreased photosynthesis capacity, and a change in biomass partitioning between different sink tissues as a result of salt stress.…”

“…De Pascale et al (2001) and Wu & Kubota (2008) reported that moderate salinity (40-60 mM) had a positive effect on lycopene accumulation, while Massaretto et al (2018) found that lycopene concentration increased under high salt stress (100 mM) in both a commercial cultivar and a tomato landrace. On the contrary, a negative or marginal effect on carotenoid accumulation was reported under salt stress (Dorais et al, 2000;Krauss et al, 2006;Van Meulebroek et al, 2012;Van Meulebroek et al, 2016;Ehret et al, 2013). Even when carotenoids content variation in response to salinity seem to correspond to a cultivar-dependent characteristic, it might be related to the ability of the plant to cope with stress and oxidative damage.…”

The Antioxidant Profile Evaluation of Some Tomato Landraces with Soil Salinity Tolerance Correlated with High Nutraceuticaland Functional Value

“…Although most research confirms the growth of Lyccontent in salinity conditions [69][70][71], there are a few studies that infirm this hypothesis [23,72]. Therefore, the genetic requirements and the specific conditions in which the genotype was cultivated are decisive factors on the capacities of biosynthesis of Lyc, alongside other evident factors such as ripening stage and cultivation technologies (e.g., field/greenhouse, organic/non-organic) [32].…”

Current Challenges in Plant Eco-Metabolomics

“…For example, [ 72 ] investigated how the metabolome of tomato fruits changes with different salinity levels and observed carotenoid accumulation with higher salinity. [ 71 ] found plastic responses of leaves of different maize lines to different temperature conditions and identified metabolites associated with heat and cold stress.…”