ARS | Publication request: WAXY INTRON PHYLOGENY OF WILD TOMATOES

Submitted to: Plant and Animal Genome Conference Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: January 24, 2000
Publication Date: N/A

Technical Abstract: The cultivated tomato, Solanum lycopersicum (=Lycopersicon esculentum) has nine wild species relatives, distributed in the Andes Mountains, mostly from central Ecuador to northern Chile. The taxonomy of the group varies among authors, with big discrepancies in interspecific relationships proposed depending on whether the species are classified by morphological or biological criteria. Some species are narrowly endemic, while one species, S. peruvianum, are widespread throughout much of the range of the group. The purpose of this research was to investigate interspecific relationships based on DNA sequences of intron regions of approximately one-third the waxy gene. Data of 602 base pairs of waxy sequences were generated for 44 accessions, with a concentration on the highly polymorphic and widespread species S. peruvianum, using S. lycopersicoides as outgroup. The data support a basal clade of the strictly allogamous species S. habrochaites, S. chilense, and S. pennellii, and southern Peruvian accessions of S. peruvianum. A derived clade contains northern Peruvian accessions of S. peruvianum and the remaining autogamous species. These data support S. peruvianum as paraphyletic, with a geographical (north, south) component to its variation. The self-compatible species show greatly reduced variability relative to the self-incompatible species. These results show areas of agreement and disagreement with prior classifications and molecular studies using nuclear RFLPs and chloroplast DNA restriction sites. The data suggest that wild tomatoes need reevaluation relative to species boundaries of S. peruvianum and of interspecific classifications.