title: Salinity Adaptation and the Contribution of Parental Environmental Effects in Medicago truncatula.
abstract: High soil salinity negatively influences plant growth and yield. Some taxa have evolved mechanisms for avoiding or tolerating elevated soil salinity, which can be modulated by the environment experienced by parents or offspring. We tested the contribution of the parental and offspring environments on salinity adaptation and their potential underlying mechanisms. In a two-generation greenhouse experiment, we factorially manipulated salinity concentrations for genotypes of Medicago truncatula that were originally collected from natural populations that differed in soil salinity. To compare population level adaptation to soil salinity and to test the potential mechanisms involved we measured two aspects of plant performance, reproduction and vegetative biomass, and phenological and physiological traits associated with salinity avoidance and tolerance. Saline-origin populations had greater biomass and reproduction under saline conditions than non-saline populations, consistent with local adaptation to saline soils. Additionally, parental environmental exposure to salt increased this difference in performance. In terms of environmental effects on mechanisms of salinity adaptation, parental exposure to salt spurred phenological differences that facilitated salt avoidance, while offspring exposure to salt resulted in traits associated with greater salt tolerance. Non-saline origin populations expressed traits associated with greater growth in the absence of salt while, for saline adapted populations, the ability to maintain greater performance in saline environments was also associated with lower growth potential in the absence of salt. Plastic responses induced by parental and offspring environments in phenology, leaf traits, and gas exchange contribute to salinity adaptation in M. truncatula. The ability of plants to tolerate environmental stress, such as high soil salinity, is likely modulated by a combination of parental effects and within-generation phenotypic plasticity, which are likely to vary in populations from contrasting environments.
authors.affiliation: Department of Plant Pathology, University of California Davis, Davis, California, United States of America.
authors.forename: Ken S
authors.initials: KS
authors.lastname: Moriuchi
authors.affiliation: Molecular and Computational Biology, University of Southern California, Los Angeles, California, United States of America.|Department of Plant Biology, Michigan State University, Lansing, Michigan 48824, United States of America.
authors.forename: Maren L
authors.initials: ML
authors.lastname: Friesen
authors.affiliation: Department of Plant Pathology, University of California Davis, Davis, California, United States of America.|Plant Cell Biotechnology, Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal.
authors.forename: Matilde A
authors.initials: MA
authors.lastname: Cordeiro
authors.affiliation: Centre of Biotechnology of Borj Cedria, B.P. 901, Hammam-Lif, Tunisia.
authors.forename: Mounawer
authors.initials: M
authors.lastname: Badri
authors.affiliation: Molecular and Computational Biology, University of Southern California, Los Angeles, California, United States of America.
authors.forename: Wendy T
authors.initials: WT
authors.lastname: Vu
authors.affiliation: Molecular and Computational Biology, University of Southern California, Los Angeles, California, United States of America.
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Main
authors.affiliation: Centre of Biotechnology of Borj Cedria, B.P. 901, Hammam-Lif, Tunisia.
authors.forename: Mohamed Elarbi
authors.initials: ME
authors.lastname: Aouani
authors.affiliation: Molecular and Computational Biology, University of Southern California, Los Angeles, California, United States of America.
authors.forename: Sergey V
authors.initials: SV
authors.lastname: Nuzhdin
authors.affiliation: Department of Evolution and Ecology and Center for Population Biology, University of California Davis, Davis, California, United States of America.
authors.forename: Sharon Y
authors.initials: SY
authors.lastname: Strauss
authors.affiliation: Department of Biological Sciences and International Center for Tropical Botany, Florida International University, Miami, Florida, United States of America.|Kushlan Institute for Tropical Science, Fairchild Tropical Botanic Garden, Coral Gables, Florida, United States of America.
authors.forename: Eric J B
authors.initials: EJ
authors.lastname: von Wettberg
mesh_terms: D000222:Adaptation, Physiological; D000704:Analysis of Variance; D004777:Environment; D005838:Genotype; D046913:Medicago truncatula / Q000235:genetics / Q000502:physiology*; D008954:Models, Biological; D054712:Salinity