Genetic analysis of root traits associated with salt-tolerance in a barley mapping population

Brien C1, Gilbert S2, Mather D3, Tyerman SD4 and Shelden MC4

  1. Australian Plant Phenomics Facility, The Plant Accelerator, University of Adelaide, Glen Osmond, SA, Australia.
  2. Adelaide Microscopy, The University of Adelaide, Adelaide, SA, Australia.
  3. School of Agriculture, Food and Wine, The University of Adelaide, Glen Osmond, SA, Australia.
  4. ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, SA, Australia.

Abiotic stresses are major causes of crop yield losses in agriculture significantly impacting on sustainability. Barley (Hordeum vulgare L.) is the most salt-tolerant cereal crop with excellent genetic resources and therefore is a good model to study salt tolerance mechanisms in cereals. Salinity results in a reduction in root growth, however, some species can maintain root elongation at salt concentrations that inhibit root growth; an adaptive mechanism to ensure seedling establishment and maintain water and nutrient uptake. We aim to identify the key genes and pathways in barley roots that are involved in both perceiving osmotic changes in the soil and influencing root elongation, ultimately to increase salinity tolerance in crops. Barley cv. Clipper (malting barley) and Sahara (North African landrace 3771), have previously been shown to have a contrasting root growth phenotype and metabolic profile in response to the early phase of salinity stress. To further characterise these two genotypes, we have developed a method using laser ablation inductively coupled proton mass spectrometry to map the distribution of Na+ and K+, in the root tip. The results show that in response to salt stress the distribution of Na+ differs developmentally along the root tip and between genotypes. To elucidate the genetic basis for these mechanisms, a Clipper x Sahara DH mapping population has been screened for shoot and root phenotypic traits in response to salt stress. We are currently conducting a genetic analysis of the mapping population using Quantitative Trait Loci analysis and RNAseq to elucidate the genes involved in the maintenance of root elongation in response to salt stress. This study highlights the importance of utilizing spatial profiling and will provide us with a better understanding of abiotic stress response in plants at the tissue and cellular level.