Genomic characterization of a wild-like tomato accession from Arizona

Tomato domestication history has been revealed to be a highly complex
story. A major contributor to this complexity is an evolutionary
intermediate group (Solanum lycopersicum var. cerasiforme (Alef.) Voss;
SLC) between the cultivated tomato (Solanum lycopersicum var. lycopersicum
L.; SLL) and its wild relative (Solanum pimpinellifolium L.; SP). SLC
includes accessions with a broad spectrum of genomic and phenotypic
characteristics. Some of the SLC accessions were previously hypothesized
to be spreading northward from South America into Mesoamerica and that
migration probably entailed reversal to wild-like phenotypes such as
smaller fruits. Prior to this study, the northernmost confirmed extension
of the SLC was limited to northern Mexico. In this study, we employed
genomic methods to investigate the origin of a wild-like tomato found in a
garden in Scottsdale Arizona, USA. The so-called “Arizona tomato” featured
a vigorous growth habit and carried small fruits weighing 2-3 grams. Our
phylogenomic analyses revealed the identity of the Arizona tomato as a
member of the Mexican SLC population (SLC MEX). To our knowledge, this is
the first report of an SLC accession, confirmed using genomics, growing
spontaneously in Arizona. This finding could have implications for
conservation biology as well as agriculture.