A Simple and Effective Bioassay Method Suitable to Comparative In Vitro Study of Tomato Salt Tolerance at Early Development Stages.

Marat R Khaliluev,Liliya R Bogoutdinova,Galina N Raldugina,Ekaterina N Baranova

doi:10.3390/mps5010011

Abstract

In vitro evaluation of tomato seeds and seedlings for salt tolerance has undoubted advantages (high productivity, as well as stability and reproducibility of the obtained experimental data due to the maintenance of constant controlled conditions) in comparison with open-field system and pot experiments. However, even high-quality seeds greatly differ in the uniformity of germination capacity and germination energy. Heterogeneous germination in the habit and developmental stage of plant material significantly distorts the obtaining of relevant experimental data suitable for correct interpretation. In our study, we propose a simple and effective bioassay method suitable to comparative in vitro study of tomato salt tolerance using shoot apex of seedlings at the early first-true-leaf stage. Shoot apexes cultured the on the root induction medium (RIM) supplemented with 0.2 mg/L indole-3-butyric acid (IBA) and NaCl at different concentrations (0–250 mM NaCl) revealed significant differences between two tomato genotypes (line YaLF and cv. Rekordsmen) at the organismal (measurements of CO2 gas exchange), organ (rhizogenesis frequency; number and length of de novo regenerated roots; root fresh (RFW) and dry (RDW) weights; shoot fresh (SFW) and dry (SDW) weights), tissue (the average cross-sectional area of epidermal and mesophylls cotyledonary cells) and cellular (ultrastructure of chloroplast and nuclear compartments) development levels. In addition, a quantitative comparison of proline and photosynthetic pigments contents under 75 and 150 mm NaCl treatments showed a different response between two tomato genotypes. The proposed methodological approach can be used for other plants with a high response to auxin-induced rhizogenesis in vitro, as well as for the comparative in vitro assessment of other abiotic stresses.

Highlights

Tomatoes (Solanum lycopersicum L.) are the second most important vegetable crops after potatoes and are used as a valuable source of vitamins and lycopene in fresh or processed tomato products [1,2]
We propose a simple and effective bioassay method suitable to comparative in vitro study of tomato salt tolerance using shoot apex of seedlings at the early first-true-leaf stage
Shoot apexes cultured the on the root induction medium (RIM) supplemented with 0.2 mg/L indole-3-butyric acid (IBA) and NaCl at different concentrations (0–250 mM NaCl) revealed significant differences between two tomato genotypes

Summary

Introduction

Tomatoes (Solanum lycopersicum L.) are the second most important vegetable crops after potatoes and are used as a valuable source of vitamins and lycopene in fresh or processed tomato products [1,2]. In 2019, the world’s total tomato fruit production was approximately 180.7 million tons, which accounts for 1.7% (3.0 million tons) from Russia. In addition to its great practical value, the tomato has been widely used as a model plant in various basic research investigated the underlying the mechanisms of plant resistance to abiotic stresses, including salinity [4,5]. This is due to the large number of morphological traits clearly identifiable at different ontogenetic stages [6,7], detailed molecular genetic maps [8,9], and reproducible in vitro tissue culture techniques [10,11]

Methods

Results

Conclusion