A simple, non‐toxic method for separating seeds based on density, and its application in isolating Arabidopsis thaliana seed oil mutants

Premise: Seed oil is an economically important trait in Brassica oilseed crops. A novel method was developed to isolate Arabidopsis thaliana seeds with altered oil content. Methods and Results: In A. thaliana, seed oil content is correlated with seed density, with high-oil seeds being less dense than wild type and tending to float in solution, and low-oil seeds being denser and tending to sink. In contrast to previous methods, which used toxic chemicals and density gradient centrifugation, different concentrations of calcium chloride (CaCl2) were employed to separate seeds without the need for centrifugation. The method was validated using known seed oil mutants, and 120,822 T-DNA mutagenized A. thaliana lines were then screened for novel seed density phenotypes. Conclusions: A number of candidate mutants, as well as new alleles of two genes known to influence seed oil biosynthesis, were successfully isolated.