Response of Tibetan Wild Barley Genotypes to Drought Stress and Identification of Quantitative Trait Loci by Genome-Wide Association Analysis

Abstract

Tibetan wild barley has been identified to show large genetic variation and stress tolerance. A genome-wide association (GWA) analysis was performed to detect quantitative trait loci (QTLs) for drought tolerance using 777 Diversity Array Technology (DArT) markers and morphological and physiological traits of 166 Tibetan wild barley accessions in both hydroponic and pot experiments. Large genotypic variation for these traits was found; and population structure and kinship analysis identified three subpopulations among these barley genotypes. The average LD (linkage disequilibrium) decay distance was 5.16 cM, with the minimum on 6H (0.03 cM) and the maximum on 4H (23.48 cM). A total of 91 DArT markers were identified to be associated with drought tolerance-related traits, with 33, 26, 16, 1, 3, and 12 associations for morphological traits, H+K+-ATPase activity, antioxidant enzyme activities, malondialdehyde (MDA) content, soluble protein content, and potassium concentration, respectively. Furthermore, 7 and 24 putative candidate genes were identified based on the reference Meta-QTL map and by searching the Barleymap. The present study implicated that Tibetan annual wild barley from Qinghai–Tibet Plateau is rich in genetic variation for drought stress. The QTLs detected by genome-wide association analysis could be used in marker-assisting breeding for drought-tolerant barley genotypes and provide useful information for discovery and functional analysis of key genes in the future.

Characterization of Genetic Diversity and Genome-Wide Association Mapping of Three Agronomic Traits in Qingke Barley (Hordeum Vulgare L.) in the Qinghai-Tibet Plateau

“…To the best of our knowledge, few genetic studies have investigated the complex agronomic traits in Tibetan qingke barley (Zhang et al, 2019 ). Previous reports have included only a limited number of qingke barley accessions to identify potential signals of adaptation and domestication.…”

“…With the emergence of more cost-effective, high-throughput genotyping technologies, single nucleotide polymorphisms (SNPs) related to HD have been identified by genome-wide association studies (GWAS) (Pasam et al, 2012 ; Visioni et al, 2013 ; Genievskaya et al, 2018 ), PH (Alqudah et al, 2016 ; Almerekova et al, 2019 ), leaf area (Alqudah et al, 2018 ), spike architecture (Comadran et al, 2011 ) and grain yield (Ingvordsen et al, 2015 ; Xu et al, 2018 ) in barley. However, the genetic study of complex agronomic traits in qingke barley is limited (Zhang et al, 2019 ).…”

Six Underutilized Grain Crops for Food and Nutrition in China

“…With the genetic linkage maps developed on the SSR markers, 17 QTLs associated with grain width, grain length, and 1000-grain weight were identified in oat [ 47 ], and two main-effect QTLs related to plant height were observed in foxtail millet [ 48 ]. Genome-wide association studies (GWAS) have been used to identify the association between SSR markers with the nudity of oat grain [ 49 ] as well as with the photoperiod sensitivity of foxtail millet cultivars [ 50 ] and the relationships between DArT markers and the response of Tibetan wild barley genotypes to drought stress [ 51 ]. In recent years, whole genome sequencing has been used to mine useful genes in UGCs.…”

Contribution of functional genomics to identify the genetic basis of water‐deficit tolerance in barley and the related molecular mechanisms

“…Thus, by performing a GWAS analysis of 166 Tibetan wild barley accessions varying for their drought response, Zhang et al. (2019) identified QTL markers associated with tolerance. When searching for genes co‐localizing with these QTL, these authors found several H + K + ‐ATPases, which enable the transport of osmolytes such as organic acids, and also of K + between apoplast and cytoplasm.…”

“…When performing GWAS analysis of 166 Tibetan wild barley accessions, Zhang et al. (2019) determined QTL associated with peroxidase and catalase activity under drought stress, and identified six genes encoding peroxidases close to the markers associated with better tolerance. H 2 O 2 scavenging appears as a key process conferring drought tolerance since two genes coding for catalases were identified as candidates in QTL associated with tolerance traits at germination and seedling stages when testing 60 Egyptian contrasted genotypes (Moursi et al., 2020).…”