Isolation and Analysis of Oxalic Acid-Insensitive Mutant of Arabidopsis thaliana

Oxalic acid (OA) is inhibitory to many plant pathogenic fungi. To further characterize the molecular mechanism of OA inhibition in fungal pathogenesis, OA-insensitive mutants from a chemical inducible Arabidopsis mutant library (about 6000 lines) were screened using MS medium (calcium free) containing 1.2 mmol/L OA and 10 μmol/L estradiol. Harvested putative mutants were collected separately. Individual lines of mutants were screened again on modified MS medium containing OA. The mutants D33, D74, D154, D282, and D630 with enhanced OA resistance were obtained. The T-DNA flanking sequences were amplified by TAIL-PCR. The sequences were blasted against TAIR database. The result indicated that the T-DNA junctions of mutant D33 was inserted between At2g39720 (zinc finger) and At2g39730 (Rubisco activase), and the T-DNA junctions of the other four mutants were the same, all inserted in the same site of the first intron of At5g10450 (14-3-3 protein GF14 lambda).