The Effects of Salinity on the Anatomy and Gene Expression Patterns in Leaflets of Tomato cv. Micro-Tom

Abstract

Salinity is a form of abiotic stress that impacts growth and development in several economically relevant crops and is a top-ranking threat to agriculture, considering the average rise in the sea level caused by global warming. Tomato is moderately sensitive to salinity and shows adaptive mechanisms to this abiotic stressor. A case study on the dwarf tomato model Micro-Tom is here presented in which the response to salt stress (NaCl 200 mM) was investigated to shed light on the changes occurring at the expression level in genes involved in cell wall-related processes, phenylpropanoid pathway, stress response, volatiles’ emission and secondary metabolites’ production. In particular, the response was analyzed by sampling older/younger leaflets positioned at different stem heights (top and bottom of the stem) and locations along the rachis (terminal and lateral) with the goal of identifying the most responsive one(s). Tomato plants cv. Micro-Tom responded to increasing concentrations of NaCl (0-100-200-400 mM) by reducing the leaf biomass, stem diameter and height. Microscopy revealed stronger effects on leaves sampled at the bottom and the expression analysis identified clusters of genes expressed preferentially in older or younger leaflets. Stress-related genes displayed a stronger induction in lateral leaflets sampled at the bottom. In conclusion, in tomato cv. Micro-Tom subjected to salt stress, the bottom leaflets showed stronger stress signs and response, while top leaflets were less impacted by the abiotic stressor and had an increased expression of cell wall-related genes involved in expansion.

Tomato responses to salinity stress: From morphological traits to genetic changes

“…Other up-regulated genes in the salt-stressed tomato plants were those coding for heat shock transcription factor HSF30 (Hoffmann et al, 2021). In another experiment, in which tomato cultivar Yanfen 210 was treated with seawater at different concentrations (10%, 20% and 30%), a significant differential change was recorded in the expression of 509 genes, 40.67% of which were up-regulated, while 59.33% down-regulated.…”

Nanoporous Quercetin-Loaded Silicon-Stabilized Hybrid Lipid Nanoparticles Alleviate Salt Stress in Tomato Plants

“…Micro-Phenotypes of Treated/Untreated "Micro-Tom" Leaves under Control and Stress Conditions. The addition of NaCl caused a mild salinity stress: after the growth of the plants, the soil electrical conductivity (EC) increased from 0.9−1 to >4.95 mS (Table S2), which corresponds to a slightly saline soil as previously reported, 1 while the pH values did not show statistically significant changes.…”

“…Salinity negatively impacts both vegetative and reproductive growth and, therefore, the final yield of economically important crops such as tomato (Solanum lycopersicum L.). 1 Finding sustainable ways to tackle, on a medium-to long-term perspective, the impact of (a)biotic stresses on crops is a major challenge in the context of climate change and to meet the food demand of the ever-growing world population. 2,3 The use of nanotechnology for agronomical applications (i.e., phytonanotechnology 3 ) offers several advantages to agriculture by improving germination, 4 boosting production while minimizing losses, 5 and enhancing the content of bioactive molecules 6 and the resilience to exogenous stresses in plants.…”

Altered anatomical appraisal of mung bean (Vigna radiata (L.) Wilczek) under salinity stress

“…Both collenchyma and parenchyma lost their regular contours with increasing salt concentrations. Under control conditions, the spongy parenchyma was characterized by scattered cells separated by air spaces but it became denser under stress conditions, since the intercellular spaces decreased (Hoffmann et al, 2021).…”