title: Meta-analysis of major QTL for abiotic stress tolerance in barley and implications for barley breeding.
abstract: We projected meta-QTL (MQTL) for drought, salinity, and waterlogging tolerance to the physical map of barley through meta-analysis. The positions of these MQTL were refined and candidate genes were identified. Drought, salinity and waterlogging are three major abiotic stresses limiting barley yield worldwide. Breeding for abiotic stress-tolerant crops has drawn increased attention, and a large number of quantitative trait loci (QTL) for drought, salinity, and waterlogging tolerance in barley have been detected. However, very few QTL have been successfully used in marker-assisted selection (MAS) in breeding. In this study, we summarized 632 QTL for drought, salinity and waterlogging tolerance in barley. Among all these QTL, only 195 major QTL were used to conduct meta-analysis to refine QTL positions for MAS. Meta-analysis was used to map the summarized major QTL for drought, salinity, and waterlogging tolerance from different mapping populations on the barley physical map. The positions of identified meta-QTL (MQTL) were used to search for candidate genes for drought, salinity, and waterlogging tolerance in barley. Both MQTL3H.4 and MQTL6H.2 control drought tolerance in barley. Fine-mapped QTL for salinity tolerance, HvNax4 and HvNax3, were validated on MQTL1H.4 and MQTL7H.2, respectively. MQTL2H.1 and MQTL5H.3 were also the target regions for improving salinity tolerance in barley. MQTL4H.4 is the main region controlling waterlogging tolerance in barley with fine-mapped QTL for aerenchyma formation under waterlogging conditions. Detected and refined MQTL and candidate genes are crucial for future successful MAS in barley breeding.
authors.affiliation: School of Land and Food, University of Tasmania, P.O. Box 46, Kings Meadows, Tasmania, TAS 7249, Australia.
authors.forename: Xuechen
authors.initials: X
authors.lastname: Zhang
authors.affiliation: School of Land and Food, University of Tasmania, P.O. Box 46, Kings Meadows, Tasmania, TAS 7249, Australia.
authors.forename: Sergey
authors.initials: S
authors.lastname: Shabala
authors.affiliation: School of Biological Sciences, University of Tasmania, Private Bag 55, Hobart, TAS 7001, Australia.
authors.forename: Anthony
authors.initials: A
authors.lastname: Koutoulis
authors.affiliation: School of Land and Food, University of Tasmania, P.O. Box 46, Kings Meadows, Tasmania, TAS 7249, Australia.
authors.forename: Lana
authors.initials: L
authors.lastname: Shabala
authors.affiliation: School of Land and Food, University of Tasmania, P.O. Box 46, Kings Meadows, Tasmania, TAS 7249, Australia. Meixue.Zhou@utas.edu.au.
authors.forename: Meixue
authors.identifier: http://orcid.org/0000-0003-3009-7854
authors.initials: M
authors.lastname: Zhou
mesh_terms: D055864:Droughts; D005819:Genetic Markers; D001467:Hordeum / Q000235:genetics*; D000069600:Plant Breeding / Q000379:methods; D040641:Quantitative Trait Loci; D015203:Reproducibility of Results; D054712:Salinity; D012641:Selection, Genetic; D013312:Stress, Physiological / Q000235:genetics*
chemical_list: D005819:Genetic Markers
keywords: Barley; Drought; Meta-analysis; Salinity; Waterlogging