Screening And Identification Of Recessive Monogenic Salt-tolerance Mutants In Arabidopsis Thaliana

We obtain two recessive monogenic salt-tolerance mutants from Co60-γ-mutagenized Arabidopsis thaliana M2 populations. The effect of NaCl on the structure of vegetative organa in Arabidopsis thaliana was further studied and through a RAPD analysis on salt-tolerance mutants of Arabidopsis thaliana, a 1200bp DNA fragment probably related to the salt-tolerance gene was get.Wild Arabidopsis thaliana seeds were mutagenized with y-ray, and M2 populations were screened in the medium containing 200mmol/L NaCl. 352 potential high-salt-tolerance mutants were selected from 80,000 M2 seedlings, and 4 of this M2 mutants showed high-salt-tolerance in their M3 generation. This high-salt-tolerance mutants were backcrossed with the wild type Arabidopsis thaliana. All F1 seedlings showed wild-type salt-sensibility, and Two of four mutants were detected that the proportion of the salt-tolerance seedlings to salt-sensibility seedlings was 1:3 in F2 progenys. The results of genetic analysis suggested that this mutants have a monogenic recessive mutation in a nuclear gene.The effect of NaCl on the structure of vegetative organ in Arabidopsis thaliana was studied. The results showed with the increasing of NaCl concentration, the phenomenon of carnification could be found in the leaves of Arabidopsis thaliana . Under the stress of NaCl lower than 100 mmol/L, the tissue structure of root had no distinct difference from the control. When the concentration of NaCl was higher than 250 mmol/L, the stained color of safranine was deep but not even, and color in fibrovascular tissue and peripheral cortex cell were deeper than that around fibrovascular tissue.Wild type Arabidopsis thaliana and two salt-tolerance mutants were used for RAPD analysis. Four out of 150 random primers could detect DNA polymorphism between the two mutants and the wild type Arabidopsis thaliana, which provided a strong evidence for the truth of the mutants. Only one primer gave a specific DNA fragment about 1200bp which two mutants own but the parent don't. We drew a preliminary conclusion that the fragment might be related to the salt-tolerance gene.