Yeast functional screen to identify genes conferring salt stress tolerance in Salicornia europaea

Yoshiki Nakahara,Mineo Shibasaka,Kosuke Yamamoto,Shogo Sawabe,Maki Katsuhara,Masanori Suzuki,Hikaru Sakamoto,Suguru Oguri,Kenta Kainuma

doi:10.3389/fpls.2015.00920

Abstract

Salinity is a critical environmental factor that adversely affects crop productivity. Halophytes have evolved various mechanisms to adapt to saline environments. Salicornia europaea L. is one of the most salt-tolerant plant species. It does not have special salt-secreting structures like a salt gland or salt bladder, and is therefore a good model for studying the common mechanisms underlying plant salt tolerance. To identify candidate genes encoding key proteins in the mediation of salt tolerance in S. europaea, we performed a functional screen of a cDNA library in yeast. The library was screened for genes that allowed the yeast to grow in the presence of 1.3 M NaCl. We obtained three full-length S. europaea genes that confer salt tolerance. The genes are predicted to encode (1) a novel protein highly homologous to thaumatin-like proteins, (2) a novel coiled-coil protein of unknown function, and (3) a novel short peptide of 32 residues. Exogenous application of a synthetic peptide corresponding to the 32 residues improved salt tolerance of Arabidopsis. The approach described in this report provides a rapid assay system for large-scale screening of S. europaea genes involved in salt stress tolerance and supports the identification of genes responsible for such mechanisms. These genes may be useful candidates for improving crop salt tolerance by genetic transformation.

Highlights

Soil salinity is one of the most critical environmental factors limiting the productivity of agricultural crops, with adverse effects on germination, plant growth and crop yield
Functional Screening for Genes Involved in Salt Tolerance in S. europaea
To identify genes involved in salt tolerance in S. europaea at the mature stage, we performed functional screening of its cDNA library in a yeast expression vector

Summary

Introduction

Soil salinity is one of the most critical environmental factors limiting the productivity of agricultural crops, with adverse effects on germination, plant growth and crop yield. The problem has been aggravated by agricultural practices such as irrigation. Worldwide 20% of total cultivated lands and 33% of irrigated agricultural lands are afflicted by high salinity. The salinized areas are increasing at a rate of 10% annually for various reasons, including low precipitation, high surface evaporation, weathering of native rocks, irrigation with saline water, Abbreviations: SGR-Ura, synthetic complete media containing 2% galactose and 1% raffinose, and lacking uracil; VC, vector control. Salt tolerance in Salicornia europaea and poor cultural practices. It has been estimated that more than 50% of the arable land would be salinized by the year 2050 (Jamil et al, 2011)

Methods

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Conclusion