Sequence evolution and expression regulation of stress-responsive genes in natural populations of wild tomato

PLoS One. 2013 Oct 18;8(10):e78182. doi: 10.1371/journal.pone.0078182. eCollection 2013.

Abstract

The wild tomato species Solanum chilense and S. peruvianum are a valuable non-model system for studying plant adaptation since they grow in diverse environments facing many abiotic constraints. Here we investigate the sequence evolution of regulatory regions of drought and cold responsive genes and their expression regulation. The coding regions of these genes were previously shown to exhibit signatures of positive selection. Expression profiles and sequence evolution of regulatory regions of members of the Asr (ABA/water stress/ripening induced) gene family and the dehydrin gene pLC30-15 were analyzed in wild tomato populations from contrasting environments. For S. chilense, we found that Asr4 and pLC30-15 appear to respond much faster to drought conditions in accessions from very dry environments than accessions from more mesic locations. Sequence analysis suggests that the promoter of Asr2 and the downstream region of pLC30-15 are under positive selection in some local populations of S. chilense. By investigating gene expression differences at the population level we provide further support of our previous conclusions that Asr2, Asr4, and pLC30-15 are promising candidates for functional studies of adaptation. Our analysis also demonstrates the power of the candidate gene approach in evolutionary biology research and highlights the importance of wild Solanum species as a genetic resource for their cultivated relatives.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptation, Physiological / genetics
  • Adaptation, Physiological / physiology
  • Droughts
  • Evolution, Molecular
  • Lycopersicon esculentum / genetics*
  • Plant Proteins / genetics*

Substances

  • Plant Proteins

Grant support

This work was funded by grant STE 325/13-1 from the German Research Foundation to WS and a fellowship from the Graduiertenförderung nach dem Bayerischen Eliteförderungsgesetz to IF. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.