title: Nucleotide polymorphism in the drought responsive gene Asr2 in wild populations of tomato.
abstract: The Asr gene family (named after abscicic acid [ABA], stress, ripening), exclusively present in plant genomes, is involved in transcriptional regulation. Its members are up-regulated in roots and leaves of water- or salt-stressed plants. In previous work, evidence of adaptive evolution (as inferred from synonymous and nonsynonymous divergence rates) has been reported for Asr2 in Solanum chilense and S. arcanum, two species dwelling in habitats with different precipitation regimes. In this paper we investigate patterns of intraspecific nucleotide variation in Asr2 and the unlinked locus CT114 in S. chilense and S. arcanum. The extent of nucleotide diversity in Asr2 differed between species in more than one order of magnitude. In both species we detected evidence of non-neutral evolution, which may be ascribed to different selective regimes, potentially associated to unique climatic features, or, alternatively, to demographic events. The results are discussed in the light of demographic and selective hypotheses.
authors.affiliation: Departamento de Fisiología, Biología Molecular y Celular and IFIByNE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, C1428EHA Buenos Aires, Argentina.
authors.forename: Mariano I
authors.initials: MI
authors.lastname: Giombini
authors.forename: Nicolás
authors.initials: N
authors.lastname: Frankel
authors.forename: Norberto D
authors.initials: ND
authors.lastname: Iusem
authors.forename: Esteban
authors.initials: E
authors.lastname: Hasson
mesh_terms: D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D005828:Genetics, Population; D018745:Genome, Plant; D006239:Haplotypes; D018551:Solanum lycopersicum / Q000235:genetics*; D010940:Plant Proteins / Q000235:genetics*; D011110:Polymorphism, Genetic
chemical_list: C091854:Asr2 protein, Lycopersicon esculentum; D010940:Plant Proteins