Genome-wide association analysis of potassium uptake and translocation rates under low K stress in Tibetan wild barley

Abstract

A low level of available potassium (K) in soils is a major factor restricting crop growth and production. In earlier studies we found that Tibetan wild barley has a wider variation in low K stress tolerance than cultivated barley. In this study, we performed a genome-wide association analysis of 179 Tibetan wild barley (Hordeum vulgare L.) accessions exposed to low K stress and investigated the associations of K uptake rate (KUR), K translocation rate (KTR) and other K metabolism traits with 11,013 diversity arrays technology markers. The results showed that there were significant differences in tissue K concentration and content, KUR and KTR among the wild barley accessions analyzed. Scores for all traits showed a normal distribution. Three significant quantitative trait loci (QTLs) for KUR and KTR were identified and located on 6H and 1H. These QTLs were found to be associated with the cation/H(+) antiporter and cyclic nucleotide gated channel. A number of unique candidate genes associated with K-related signals, including K channels, K transporters and ethylene-related genes, were also identified. The K channels and K transporters involved in K uptake and translocation, respectively, were closely associated with KUR in response to low K stress. The present study highlights the potential of Tibetan wild barley to provide elite candidate genes for the improvement of K use efficiency of barley.