Transgenic Approaches of Improving Tomato (Solanum lycopersicum) to Salt Stress Tolerance

Mengistu Birhanu

doi:10.7176/jbah/10-14-01

Abstract

Environmental stresses mainly drought and salinity are now becoming potential threats for global agricultural production. Being a tropical crop, tomato is produced in warm and dry regions of the world, where salt stress is limiting the yield potential of the crop. Plant defense response to salt tolerance is very complex in which many morphological, physiological, and molecular modifications are enhanced. Although considerable effort has been made in developing salt tolerant tomato cultivars through conventional breeding, it has met with limited success due to the complex, multigenic nature of the trait and developmental stage regulated phenomenon of the salt tolerance response. Genetic engineering is an alternative approach to understand the mechanisms of salinity tolerance and apply the knowledge obtained to generate salt tolerant tomatoes. This review aims to highlight the latest developments in biotechnological techniques of improving tomato tolerance to salt stress. Recently, there have been many attempts to enhance tomato tolerance to salt stress including introduction and/or modifications of various genes involved in regulatory, signaling pathways, detoxifying enzymes and genes encoding functional and structural proteins. Plasma membrane Na+/H+ antiporters (SOS) and vacuolar Na+/H+ antiporters (NHXn), Dehydrin (DHN), Choline Oxidase (codA), and ROS scavengers have been the major genes targeted in many studies for developing salt stress tolerant transgenic tomato. Moreover, promising results have reported on the identification and use of various abiotic stress responsive elements and/or transcription factors such as SlDREB2, SL-ZH13, Sl-ERF.B.3, AREB, NAC-Type and WRKY TFs, which positively regulate the expression of the downstream genes in transgenic tomato with response to salt stress. Keywords׃ Salt Stress, Tomato, Transgenic, Transcription Factor DOI: 10.7176/JBAH/10-14-01 Publication date:July 31st 2020

Highlights

Environmental stresses especially drought and salinity are becoming potential threats for global agricultural production
The result from this study indicated that the growth attributes such as fresh weight, primary root length, and number of lateral roots per seedling of the transgenic tomato lines were significantly higher than the WT under 150 mM NaCl
Efforts have been made both in model and other cultivated crops including tomato to improve salt stress through conventional breeding

Summary

Introduction

Environmental stresses especially drought and salinity are becoming potential threats for global agricultural production. Tomato (Solanum lycopersicum) belongs to Solonacea family and is one of the most important vegetable crops, which is produced for the fresh market and processed products such as tomato juice, paste, puree, ketchup, sauce, and salsa. It is a major source of minerals, vitamins, and provides health benefits in human consumption (Robertson and Labate, 2007). Though grown in a wide range of areas, the major share of tomato production is mainly concentrated in a warm and dry regions including Mediterranean Sea, Southern and Western parts of USA and Mexico (Foolad, 2004). Due to frequent occurrence of soil and/or water salinity, the production of tomato in such warm and dry areas is constrained by salt stress

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Conclusion