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Salinity and drought have a huge impact on agriculture since there are few areas free of these abiotic stresses and the problem continues to increase. In tomato, the most important horticultural crop worldwide, there are accessions of wild-related species with a high degree of tolerance to salinity and drought. Thus, the finding of insertional mutants with other tolerance levels could lead to the identification and tagging of key genes responsible for abiotic stress tolerance. To this end, we are performing an insertional mutagenesis programme with an enhancer trap in the tomato wild-related species Solanum pennellii. First, we developed an efficient transformation method which has allowed us to generate more than 2,000 T-DNA lines. Next, the collection of S. pennelli T0 lines has been screened in saline or drought conditions and several presumptive mutants have been selected for their salt and drought sensitivity. Moreover, T-DNA lines with expression of the reporter uidA gene in specific organs, such as vascular bundles, trichomes and stomata, which may play key roles in processes related to abiotic stress tolerance, have been identified. Finally, the growth of T-DNA lines in control conditions allowed us the identification of different development mutants. Taking into account that progenies from the lines are being obtained and that the collection of T-DNA lines is going to enlarge progressively due to the high transformation efficiency achieved, there are great possibilities for identifying key genes involved in different tolerance mechanisms to salinity and drought.

WileyGarcía-Abellán, JO.; Fernández-García, N.; López-Berenguer, C.; Egea, I.; Flores, FB.; Angosto, T.; Capel, J.... (2015). The tomato res mutant which accumulates JA in roots in non-stressed conditions restores cell structure alterations under salinity. Physiologia Plantarum. 155(3): 296-314. doi:10.1111/ppl.12320. This article is protected by copyright. All rights reserved This article has been accepted for publication and undergone full peer review but has not been through the copyediting, typesetting, pagination and proofreading process, which may lead to differences between this version and the Version of Record. Please cite this article as doi: 10.1111/ppl.12320 This article is protected by copyright. All rights reserved Jasmonic acid (JA) regulates a wide spectrum of plant biological processes, from plant development to stress defense responses. The role of JA in plant response to salt stress is scarcely known, and even less known is the specific response in root, the main plant organ responsible for ionic uptake and transport to the shoot. Here we report the characterization of the first tomato (Solanum lycopersicum) mutant, named res (restored cell structure by salinity), that accumulates JA in roots prior to exposure to stress. The res tomato mutant presented remarkable growth inhibition and displayed important morphological alterations and cellular disorganization in roots and leaves under control conditions, while these alterations disappeared when the res mutant plants were grown under salt stress.Reciprocal grafting between res and wild type (WT) (tomato cv. Moneymaker) indicated that the main organ responsible for the development of alterations was the root. The JA-signaling pathway is activated in res roots prior to stress, with transcripts levels being even higher in control condition than in salinity. Future studies on this mutant will provide significant advances in the knowledge of JA role in root in salt stress tolerance response, as well as in the energy trade-off between plant growth and response to stress.Abbreviations -ANOVA, analysis of variance; COI1, coronatine insensitive 1; GC-MS, gas chromatography coupled to mass spectrometry; ICP-OES, inductively coupled plasma optical emission spectrometry; JA, jasmonic acid; JAR1, jasmonoyl isoleucine conjugate synthase 1; JAZ1, jasmonate ZIM domain protein 1; LOXD, lipoxygenase D; LSD, least significant difference test;MeJA, methyl-jasmonate; MS, Murashige-Skoog medium; NaCl, sodium chloride; RH, relative humidity; SE, standard error; TEM, transmission electron microscopy; UBI, ubiquitin; WT, wild-type. IntroductionDevelopment of crops tolerant to stress is vital to meet the growing food demand through sustainable agriculture (Godfray et al. 2010), since traditional agriculture and conventional breeding cannot uphold this increasing demand, partly because of the increasing salt stress impact due to environmental and climatic changes (Shaik and Ramakrishna 2014). Indeed, increased salinization of arable land is expected to have devastat...