Submitted to: Frontiers in Plant Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/2017
Publication Date: 6/29/2017
Citation: Yu, L. 2017. Identification of single-nucleotide polymorphic loci associated with biomass yield under water deficit in alfalfa (Medicago sativa L.) using genome-wide sequencing and association mapping. Frontiers in Plant Science. doi: 10.3389/fpls.2017.01152. Interpretive Summary: The production of alfalfa is challenged by adverse environmental stress factors such as drought and other stresses. Developing drought resistance alfalfa is an important breeding target for enhancing alfalfa productivity in arid and semi-arid regions. To understand the genetic bases of droguth resistance in alfalfa, we screened 200 alfalfa accessions for drought tolerance in a field trail in 2015-2016. Biomass yield under drought was measured and DNA was extracted from each individual and sequenced. Marker-trait assciaition identified 22 marker loci associated with biomass yield under drought stress. With further investigation, these markers can be used for marker-assisited selection in breeding programs for developing alfalfa cultivars with enhanced resistance to drought and other eviromental stresses.
Technical Abstract: Alfalfa is a worldwide grown forage crop and is important due to its high biomass production and nutritional value. However, the production of alfalfa is challenged by adverse environmental stress factors such as drought and other stresses. Developing drought resistance alfalfa is an important breeding target for enhancing alfalfa productivity in arid and semi-arid regions. In the present study, we used genotyping-by-sequencing and genome-wide association and identified 22 marker loci associated with biomass yield under drought in the field in a diverse germplasm of the alfalfa. The comparison of associated markers among three sets of data obtained in three harvest periods showed identical for most of the markers, indicating the agreement of marker-trait associations and stress treatments among different harvests. Similar results in the loci associated with biomass yield by drought were also found in previous reports. Our results suggest that biomass yield under drought is a complex trait with polygenic inheritance in alfalfa. The BLAST search of the flanking sequences of the associated loci against DNA databases identified several stress responsive genes linked to the drought associated loci. With further investigation, those markers closely linked to drought resistance can be used for MAS to accelerate the development of new alfalfa cultivars with improved resistance to drought and other abiotic stresses.