Annabelle Damerum1, Hazel K Smith2,3, Gjj Clarkson3, Maria José Truco4, Richard W Michelmore4, Gail Taylor5,6. 1. Department of Plant Sciences, University of California, Davis, 95616, CA, USA. 2. School of Biological Sciences, University of Southampton, Hampshire, SO17 1BJ, UK. 3. Present address: Vitacress Salads, Lower Link Farm, St Mary Bourne, SP11 6DB, Hampshire, UK. 4. The Genome Centre, University of California, Davis, 95616, CA, USA. 5. Department of Plant Sciences, University of California, Davis, 95616, CA, USA. gtaylor@ucdavis.edu. 6. School of Biological Sciences, University of Southampton, Hampshire, SO17 1BJ, UK. gtaylor@ucdavis.edu.
Abstract
BACKGROUND: Water supply limits agricultural productivity of many crops including lettuce. Identifying cultivars within crop species that can maintain productivity with reduced water supply is a significant challenge, but central to developing resilient crops for future water-limited climates. We investigated traits known to be related to water-use efficiency (WUE) and yield in lettuce, a globally important leafy salad crop, in a recombinant inbred line (RIL) lettuce mapping population, produced from a cross between the cultivated Lactuca sativa L. cv. Salinas and its wild progenitor L. serriola L. RESULTS: Wild and cultivated lettuce differed in their WUE and we observed transgressive segregation in yield and water-use traits in the RILs. Quantitative trait loci (QTL) analysis identified genomic regions controlling these traits under well-watered and droughted conditions. QTL were detected for carbon isotope discrimination, transpiration, stomatal conductance, leaf temperature and yield, controlling 4-23 % of the phenotypic variation. A QTL hotspot was identified on chromosome 8 that controlled carbon isotope discrimination, stomatal conductance and yield under drought. Several promising candidate genes in this region were associated with WUE, including aquaporins, late embryogenesis abundant proteins, an abscisic acid-responsive element binding protein and glutathione S-transferases involved in redox homeostasis following drought stress were also identified. CONCLUSIONS: For the first time, we have characterised the genetic basis of WUE of lettuce, a commercially important and water demanding crop. We have identified promising candidate genomic regions determining WUE and yield under well-watered and water-limiting conditions, providing important pre-breeding data for future lettuce selection and breeding where water productivity will be a key target.
BACKGROUND:Water supply limits agricultural productivity of many crops including lettuce. Identifying cultivars within crop species that can maintain productivity with reduced water supply is a significant challenge, but central to developing resilient crops for future water-limited climates. We investigated traits known to be related to water-use efficiency (WUE) and yield in lettuce, a globally important leafy salad crop, in a recombinant inbred line (RIL) lettuce mapping population, produced from a cross between the cultivatedLactuca sativa L. cv. Salinas and its wild progenitor L. serriola L. RESULTS: Wild and cultivated lettuce differed in their WUE and we observed transgressive segregation in yield and water-use traits in the RILs. Quantitative trait loci (QTL) analysis identified genomic regions controlling these traits under well-watered and droughted conditions. QTL were detected for carbon isotope discrimination, transpiration, stomatal conductance, leaf temperature and yield, controlling 4-23 % of the phenotypic variation. A QTL hotspot was identified on chromosome 8 that controlled carbon isotope discrimination, stomatal conductance and yield under drought. Several promising candidate genes in this region were associated with WUE, including aquaporins, late embryogenesis abundant proteins, an abscisic acid-responsive element binding protein and glutathione S-transferases involved in redox homeostasis following drought stress were also identified. CONCLUSIONS: For the first time, we have characterised the genetic basis of WUE of lettuce, a commercially important and water demanding crop. We have identified promising candidate genomic regions determining WUE and yield under well-watered and water-limiting conditions, providing important pre-breeding data for future lettuce selection and breeding where water productivity will be a key target.
Authors: Pauline J Kerbiriou; Chris A Maliepaard; Tjeerd Jan Stomph; Martin Koper; Dorothee Froissart; Ilja Roobeek; Edith T Lammerts Van Bueren; Paul C Struik Journal: Front Plant Sci Date: 2016-03-30 Impact factor: 5.753