Screening Of Stress Tolerance Mutants Of Arabidopsis Thaliana

Since the plants'survival environment is varied, for development and propagation they have to feel and recognize all sorts of environmental factors in different ways to make corresponding physiology reactions and eventually adapt to the environment. However, if the environments change too drastically beyond the limitation of their normal growth and development, which plant can endure, damage to the plants might be caused. Generally, plants'stress environments usually refer to abiotic stress, including high-temperature, low-temperature, oxidation, drought, high salt and low potassium stress. Soil salinization is the main environmental factors affecting crop growth and production increase, which may lead to global crop yield losses. Therefore, it is highly important to carry on the research of the plant salt-tolerance mechanism and cultivate the salt-tolerant crop varieties. Presently, it is not very clear to understand the network concerned about controlling plants salt signal. Therefore, it is quite necessary to continue the finding of the genes related to the salt tolerance and investigation of their function.We used three different kinds of T-DNA insertion activation tagging mutant libraries to screen salt-tolerance and salt-overly-sensitive mutants. These three different activation tagging mutant libraries were: gain-of-function activation tagging mutant library, carrying pSKI015 as activation tagging vector, Basta-resistant as seletion marker;β-estradiol induced activation tagging mutant library, which were generated by PER16 carrying XVE expression system and kanamycin selection marker; Activation tagging mutant library constructed with pSKI074, kanamycin resistance as seletion marker.Salt-tolerance mutants screening on 5,000 lines from gain-of-function activation tagging mutant library and activation tagging mutant library induced byβ-estradiol was performed under the condition of 200 mmol/L NaCl in screening medium, which could significantly inhibited wild-type Arabidopsis seedling root growth. Ultimately, three lines which can steadily inherit to T2 generation were obtained, though these mutants phenotype cannot inherit to the T3 generation. Low-potassium mutants screening was carried on among 1,000 lines from activation tagging mutant library under 40μmol/L of potassium plus 150 mmol/L or 50 mmol/L NaCl in screening medium. In 150 mmol/L NaCl condition, seedling root growth of wild-type Arabidopsis was significantly inhibited at first, while in 50 mmol/L NaCl condition, the extent of the wild-type Arabidopsis seedling root growth was the maximum. Unfortunately, the steady inherited mutants were not obtained. But the work described in this thesis offered important references for the further work to gain the other mutunt plants.