|LIN, SEN - Washington State University|
|MEDINA, CESAR - Washington State University|
|BOGE, BILL - Retired ARS Employee|
|FRANSEN, STEVEN - Washington State University|
|NORBERG, STEVEN - Washington State University|
Submitted to: Biomed Central (BMC) Plant Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/24/2020
Publication Date: 7/1/2020
Publication URL: https://handle.nal.usda.gov/10113/7006017
Citation: Lin, S., Medina, C., Boge, B., Hu, J., Fransen, S., Norberg, S., Yu, L. 2020. Identification of genetic loci associated with forage quality in response to water deficit in autotetraploid alfalfa (Medicago sativa L.). Biomed Central (BMC) Plant Biology. 20. https://doi.org/10.1186/s12870-020-02520-2.
Interpretive Summary: Plant phenotypic plasticity is the ability for plants to cope with environmental factor variability. However, mechanisms by which phenotypic plasticity affects plant adaptation to environmental change remain largely unknown. It is important to identify plant functional traits in which plasticity may play a critical role in plant response to the environmental change. In the present study, we characterized 26 forage quality traits in alfalfa populations and analyzed the phenotypic plasticity of these traits in response to a gradient of water deficit. Fiber contents such as lignin, ADF and NDF decreased as drought increased. In contrast, energy traits were increased as drought increased.Genetic factors were also characterized using genotyping by sequencing and genome-wide association studies. Single nucleotide polymorphisms associated with the traits were identified. Genomic architectures for phenotypic plasticity were analyzed for each trait and compared between the traits. Genomic regions responsible for the traits were identified and characterized. The possible roles of the genetic factors affecting phenotypic plasticity of forage quality in alfalfa were discussed.
Technical Abstract: Genetic bases by which phenotypic plasticity affects plant adaptation to environmental change remain largely unknown. In the present study, we characterized genetic architecture of phenotypic plasticity for 26 forage quality traits of a selected alfalfa panel comprising 198 accessions in a field trial under a deficit irrigation gradient. Great phenotypic plasticities were found among alfalfa cultivars and landraces under water deficit treatments. The values of fiber-related traits decreased as water deficit increased, while energy-related traits increased as water deficit increased. Genetic loci associated with forage quality traits were identified using genome-wide association studies (GWAS). Putative candidate genes underlying the associated loci were found and their functions involved in plant abiotic responses were discussed. Although GWAS on forage quality have been reported, we are the first to address the genetic base of phenotypic plasticity of forage quality traits under water deficit. The information gained from the present study will be useful for the genetic improvement of alfalfa with enhanced drought/salt tolerance while maintaining forage quality.