Abstract
Temperature is a primary environmental cue for seed germination of many weeds and vegetables. To investigate the mechanism of germination regulation by temperature, we have selected five high temperature (thermoinhibition) resistant germination mutants of Arabidopsis. The seeds of trg1 shows slightly reduced sensitivity to ABA at 22 oC, and the insensitivity is apparent at higher temperature conditions. In addition, trg1 plants have shorter siliques and slightly shorter stems than the wild type. The mutation was mapped between molecular markers TJ-5 and FJ-4 at the bottom arm of chromosome 1. We sequenced all the seven predicted genes in this region, and found 14 bp deletion in At1g68560 which codes for α-xylosidase. The mutation introduces pre-mature stop codon in pro-peptide region of the precursor protein. The thermoinhibition resistant germination of trg1 seeds may be caused by disorganization of cell wall metabolism since α-xylosidase is thought to hydrolyse xyloglucan oligosaccharaides in cell wall.
