Chilling-induced water stress: variation in shoot turgor maintenance among wild tomato species from diverse habitats.
OBJECTIVE
Cultivated tomato, Solanum lycopersicum, suffers chilling induced wilting because water movement through its roots decreases with declining soil temperatures. Certain wild tomato species exhibit resistance to chilling-induced wilting, but the extent of this chilling tolerance in wild tomatoes is not known. •


METHODS
We measured shoot wilting during root chilling in wild Solanum accessions from habitats differing in elevation, temperature, and precipitation. We also measured shoot wilting during root chilling in introgression lines (ILs) with chromosome 9 segments collinear to the shoot turgor maintenance QTL stm9 region from chilling-tolerant S. habrochaites, chilling and drought-tolerant S. lycopersicoides, or drought-tolerant S. pennellii. •


RESULTS
Wild tomato species, which experience chilling temperatures (<10°C) in their native habitat, maintain shoot turgor under root chilling. Among accessions of S. lycopersicum var. cerasiforme, a typically chilling sensitive species, shoot turgor maintenance during root chilling was correlated with the precipitation of the native habitat. By contrast, S. pennellii, a species that is typically drought adapted, did not maintain turgor under root chilling. Grafted plants with roots containing S. habrochaites and S. lycopersicoides introgressions improved shoot turgor maintenance under root chilling. •


CONCLUSIONS
Resistance to chilling-induced water stress is an important adaptation to chilling temperatures in wild tomatoes. There is some overlap in adaptation to drought and chilling stress in some tomato species. Root-based resistance to chilling-induced water stress in wild tomatoes may involve orthologous gene(s).
Department of Plant Sciences, University of California-Davis, One Shields Avenue, Davis, California 95616, USA.
Hsien Ming
HM
Easlon
José Salvador Rubio
JS
Asensio
Dina A
DA
St Clair
Arnold J
AJ
Bloom
D000531:Altitude; D032461:Chromosomes, Plant / Q000235:genetics; D003080:Cold Temperature; D003681:Dehydration; D017753:Ecosystem; D060146:Ecotype; D005838:Genotype; D007178:Inbreeding; D018551:Solanum lycopersicum / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D018517:Plant Roots / Q000502:physiology; D018520:Plant Shoots / Q000502:physiology*; D013045:Species Specificity
Solanaceae; Solanum; adaptation; chilling; drought; elevation; root; tomato