AtCSP1 regulates germination timing promoted by low temperature.

An Arabidopsis gene trap line (GT606), which disrupted the AtCSP1 gene, exhibited an early germination phenotype that was affected by stratification treatment. Comparative analysis of GUS expression in seeds at the early germination stage, with or without stratification, demonstrated that AtCSP1 expression was affected by cold temperature. Evaluation of germination assays with varying concentrations of ABA or NaCl revealed a reduced sensitivity of the atcsp1 mutant to both ABA and NaCl. Taken together, these data support the hypothesis that AtCSP1 affects early stages of seed germination subsequent to stratification treatment of seeds.