Different Strategies Used by Domesticated Tomato and Wild-related Species to Confront Salt Stress

Abstract

Salinity is responsible for important yield losses in crops, among them tomato (Solanum lycopersicum), a horticultural crop of the highest agro-economic importance. Comparing the responses to salinity of domesticated tomato and wild-relative species, displaying different degrees of tolerance, could give key insights in the strategies used by the latter ones to successfully confront salt stress, as well as to identify key genes involved in such tolerance mechanisms in wild tomato species. The behaviour in salt stress condition of a tomato cultivar (cv Moneymaker) and two wild genotypes of the S. cheesmaniae and S. pennellii species, presenting an intermediate and high level of tolerance, was compared. The objective is to dissect the differential responses to the osmotic effect as well as to the ionic stress due to salinity, applying a stress level which allows maintaining long-term plant growth. From the first hours of salt stress, the two wild species are able to respond to osmotic stress avoiding dehydration, contrarily to domesticated tomato, which suggests the importance of the osmotic tolerance under salt stress. Moreover, the strategies of both wild species seem to be different as reflected by leaf temperature (LT) results, measured by non-invasive infrared thermography, which is closely linked to water loss due to transpiration. Interestingly, the uptake and solutes transport also differed among species as well as the gene expression involved in ion homeostasis. These results may allow to identifying key physiological mechanisms and genes conferring salinity tolerance in wild tomatoes, which could be further introduced in domesticated tomato.Acknowledgements. This work was financed by the MINECO, Spain (Ref. AGL2012-40150-03) and Fundación Séneca, Región de Murcia, Spain (Ref. 18973/JLI/13).