Quantitative trait loci associated with natural diversity in water-use efficiency and response to soil drying in Brachypodium distachyon.
All plants must optimize their growth with finite resources. Water use efficiency (WUE) measures the relationship between biomass acquisition and transpired water. In the present study, we performed two experiments to understand the genetic basis of WUE and other parameters of plant-water interaction under control and water-limited conditions. Our study used two inbred natural accessions of Brachypodium distachyon, a model grass species with close phylogenetic affinity to temperate forage and cereal crops. First, we identify the soil water content which causes a reduction in leaf relative water content and an increase in WUE. Second, we present results from a large phenotyping experiment utilizing a recombinant inbred line mapping population derived from these same two natural accessions. We identify QTLs associated with environmentally-insensitive genetic variation in WUE, including a pair of epistatically interacting loci. We also identify QTLs associated with constitutive differences in biomass and a QTL describing an environmentally-sensitive difference in leaf carbon content. Finally, we present a new linkage map for this mapping population based on new SNP markers as well as updated genomic positions for previously described markers. Our studies provide an initial characterization of plant-water relations in B. distachyon and identify candidate genomic regions involved in WUE.
Department of Integrative Biology and Institute for Cell and Molecular Biology, The University of Texas at Austin, United States. Electronic address: desmarais@fas.harvard.edu.
David L
DL
Des Marais
Department of Integrative Biology and Institute for Cell and Molecular Biology, The University of Texas at Austin, United States.
Samsad
S
Razzaque
Department of Integrative Biology and Institute for Cell and Molecular Biology, The University of Texas at Austin, United States.
Kyle M
KM
Hernandez
U.S. Department of Agriculture-Agricultural Research Service, Plant Science Research Unit, St. Paul, MN, United States.
David F
DF
Garvin
Department of Integrative Biology and Institute for Cell and Molecular Biology, The University of Texas at Austin, United States.
Thomas E
TE
Juenger
D058431:Brachypodium / Q000235:genetics* / Q000378:metabolism; D002874:Chromosome Mapping; D005819:Genetic Markers; D010641:Phenotype; D040641:Quantitative Trait Loci; D014867:Water / Q000378:metabolism*
D005819:Genetic Markers; D014867:Water
Abiotic stress; Brachypodium distachyon.; Epistasis; GxE; QTL mapping; Water Use Efficiency