Abstract
Salinity causes a detrimental impact on plant growth, particularly when the stress occurs during germination and early development stages. Barley is one of the most salt-tolerant crops; previously we mapped two quantitative trait loci (QTL) for salinity tolerance during germination on the short arm of chromosome 2H using a CM72/Gairdner doubled haploid (DH) population. Here, we narrowed down the major QTL to a region of 0.341 or 0.439 Mb containing 9 or 24 candidate genes belonging to 6 or 20 functional gene families according to barley reference genomes v1 and v3 respectively, using two DH populations of CM72/Gairdner and Skiff/CM72, F2 and F3 generations of CM72/Gairdner/*Spartacus CL. Two Receptor-like kinase 4 (RLPK4) v1 or Receptor-like kinase (RLK) v3 could be the candidates for enhanced germination under salinity stress because of their upregulated expression in salt-tolerant variety CM72. Besides, several insertion/deletion polymorphisms were identified within the 3rd exon of the genes between CM72 and Gairdner. The sequence variations resulted in shifted functional protein domains, which may be associated with differences in salinity tolerance. Two molecular markers were designed for selecting the locus with receptor-like protein kinase 4, and one was inside HORVU2Hr1G111760.1 or HORVU.MOREX.r3.2HG0202810.1. The diagnostic markers will allow for pyramiding of 2H locus in barley varieties and facilitate genetic improvement for saline soils. Further, validation of the genes to elucidate the mechanisms involved in enhancing salinity tolerance at germination and designing RLPK4 specific markers is proposed. For this publication, all the analysis was based on barley reference genome of 2017 (v1), and it was used throughout for consistence. However, the positions of the markers and genes identified were updated according to new genome (v3) for reference.
Highlights
Salinity is a worldwide problem affecting more than 6% of the global land area, which is more than 20% of the total arable and 50% of cropland comprising 33% of irrigated area [1]
Germination ranged from 46.7% to 99.3% in the CM72/Gairdner population and 42.7%–96.0% in the Skiff/CM72 population exposed to salinity stress
Two studies conducted on barley reported different quantitative trait loci (QTL) for salinity tolerance at germination stage and confirmed that they differed from those at the seedling stage [18]
Summary
Salinity is a worldwide problem affecting more than 6% of the global land area, which is more than 20% of the total arable and 50% of cropland comprising 33% of irrigated area [1]. Studies have identified various adaptive mechanisms in different plant parts in response to saline conditions or salinity stress that can be summarized into three: osmotic stress tolerance, Na+ or ClÀ exclusion, and tissue tolerance to accumulated Na+ or ClÀ [9] To develop an F2 population of CM72/Gairdner/*Spartacus CL segregating for salinity tolerance at germination, the CM72/Gairdner salt-tolerant DH lines, previously selected for CM72 genotype on chromosome 2H [18], were crossed with Spartacus CL and the F1 plants allowed to self-pollinate. One half was used for genotyping with InDel markers from the 2H fine-mapped region and the other half containing the embryo was grown to produce the F3 population for phenotyping salinity tolerance at germination
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
