Identification of Quantitative Trait Loci Controlling High Calcium Response in Arabidopsis thaliana

Natural variation for primary root growth response to high Ca stress in Arabidopsis thaliana was studied by screening a series of accessions (ecotypes) under high Calcium (40 mM CaCl2) conditions. The genetic basis of this variation was further investigated by QTL analysis using recombinant inbred lines from Landsberg erecta (Ler) × Cape Verde Islands (Cvi) cross. Four QTLs were identified in chromosome 1, 2 and 5,and named response to high Calcium (RHCA) 1-4. The three QTLs (RHCA1, RHCA2 and RHCA4) were further confirmed by analysis of near isogenic lines harboring Cvi introgression fragments in Ler background. Real-time PCR analysis showed that several genes associated with high Ca response including SMT1 and XHT25 have changed expression pattern between Ler and near isogenic lines. These results were useful for detecting molecular mechanisms of plants for high Ca adaption.