Abstract:

【Objective】 The objective is to investigate the relationship between thylakoid-bound ascorbate peroxidase (tAPX) and the salt tolerance. 【Method】 WT, sense-transgenic lines T2-2 (+) and T2-6 (+) of tobacco were used to measure the activities of APX and the content of hydrogen peroxide (H2O2), germination of seeds, photosynthetic rate and chorophyll fluorescence parameters under salt stress. 【Result】 Northern blot analysis confirmed that tomato thylakoid-bound ascorbate peroxidase gene (LetAPX) was transferred into the tobacco genome and the expression of LetAPX was induced by salt tolerance. Activities of APX and the capability for scavenging H2O2 of the transgenic tobacco plants were distinctly higher than those of WT under NaCl treatment. Overexpression of LetAPX in tobacco improved germination of seeds, fresh weight and dry weight of seedlings under salt stress. The photosynthetic rate and maximal photochemistry efficiency of PSII (Fv/Fm) in the transgenic plants were higher than those of WT after NaCl treatment. 【Conclusion】 These results indicate that the overexpression of LetAPX improved salt tolerance in transgenic tobacco plants.

Key words: tobacco (Nicotiana tabacum L.), NaCl stress, LetAPX, transgenic line, salt tolerance