Over-expression of SlSHN1 gene improves drought tolerance by increasing cuticular wax accumulation in tomato.

Hmoud Al-Debei,Jamal Ayad,Ayed Al-Abdallat,Shireen Hasan

doi:10.3390/ijms151119499

Hmoud Al-Debei, Jamal Ayad + Show 2 more

Open Access

https://doi.org/10.3390/ijms151119499

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Abstract

Increasing cuticular wax accumulation in plants has been associated with improving drought tolerance in plants. In this study, a cDNA clone encoding the SlSHN1 transcription factor, the closest ortholog to WIN/SHN1 gene in Arabidopsis, was isolated from tomato plant. Expression analysis of SlSHN1 indicated that it is induced in response to drought conditions. The over-expression of SlSHN1 in tomato under the control of the constitutive CaMV 35S promoter produced plants that showed mild growth retardation phenotype with shiny and dark green leaves. Scanning electron microscopy showed that the over-expression of SlSHN1 in tomato resulted in higher cuticular wax deposition on leaf epidermial tissue when compared to non-transformed plants. Expression analysis in transgenic lines over-expressing SlSHN1 indicated that several wax-related synthesis genes were induced. Transgenic tomato plants over-expressing SlSHN1 showed higher drought tolerance when compared with wild type plants; this was reflected in delayed wilting of transgenic lines, improved water status and reduced water loss rate when compared with wild type plants. In conclusion, the SlSHN1 gene can modulate wax accumulation and could be utilized to enhance drought tolerance in tomato plant.

Highlights

In many parts around the world, drought is considered a major constraint that affects plant growth and development
To identify WIN1/SHN1 orthologous gene in tomato, a bioinformatics analysis was carried out based on the full-length sequence data of the previously described WIN1/SHN1 gene in Arabidopsis (GenBank accession number: AAR20494.1)
Acyl-CoA synthetase), Solyc08g067260, Solyc03g006240, and Solyc03g121600. These results indicate that SlSHN1 is involved, either directly or indirectly, in modulating the expression of cutin synthesis-related genes in tomato

Summary

Introduction

In many parts around the world, drought is considered a major constraint that affects plant growth and development. The over-expression of SHN1/WIN1 in Arabidopsis plant resulted in improved drought tolerance and reduced transpiration rate [28,29]. The functional characterization of the SHN1/WIN1 orthologous gene in barley indicates a major role in cutin biosynthesis and the formation of adhering hulled caryopsis type [31]. Loss of function mutation and gene silencing of SlSHN3 in tomato plants resulted in reduced levels of cuticular wax and altered fruit morphology. The characterization of the closest SHN1/WIN1 orthologous gene in tomato, SlSHN1, and its role in mediating drought tolerance is described. Transgenic tomato plants over-expressing SlSHN1 showed reduced water loss rate and enhanced growth under drought conditions. The expression of wax biosynthesis genes was found to be induced in the over-expressing SlSHN1 lines

Results and Discussion

SlSHN1 Expression in Response to Drought Conditions

Cloning of SlSHN1 in Tomato

Bioinformatics Analysis

Physiological Measurements