A Efficient Method for Isolation of Arabidopsis Mutants

This paper introduces a root bending assay for isolation of Arabidopsis mutants tolerant to nutrition stress. Seeds of wild type Arabidopsis thaliana (ecotype Landersberg erecta ) were mutagenized with ethyl methyl sulfide (EMS),and M2 populations were screened for mutants. Four day old seedlings with 1 to 1.5 cm long roots were transferred from the vertical agar plates onto to a second agar medium that was supplemented with determinate stress. The seedlings were arranged in rows, and the plates were oriented vertically with the roots pointing upward. After another 4 days, the root bending seedlings were selected for putative mutants and transferred to soil to grow to maturity.Seeds from the putative mutants were screened again to determine the true mutants.By using this root bending assay we have isolated a low K + tolerant (lkt1) mutant which is caused by single recessive nuclear mutation. For lkt1 mutant screening,K +concentration of the medium was 100μmol/L because root growth of wild type seedlings was completely inhibited at or below this concentration.This root bending assay is also applicable to other type of Arabidopsis mutant isolation.