effects of overexpression of formaldehyde dehydrogenase gene from Brevibacillus brevis on the physiological characteristics of tobacco under formaldehyde stress

The faldh gene encodes the Brevibacillus brevis glutathione-dependent formaldehyde dehydrogenase (FALDH), an enzyme involved in formaldehyde metabolism. In the present work, we have investigated the physiological characteristics of transgenic faldh tobacco under formaldehyde stress. Overexpression of B. brevis FALDH confers tobacco tolerance to high HCHO concentrations. The transgenic tobacco lines had the higher biomass, produced the higher content of total proteins and soluble sugars, the lower levels of MDA, protein carbonyl (PC), and H₂O₂ as compared with the wild-type tobacco under HCHO stress. The contents of chlorophyll (Chl), including Chl a, Chl b, and the ratio of Chl a/b, and the content of anthocyanidin in transgenic plants under HCHO stress were also higher than that in wild-type tobacco. These results show that high HCHO tolerance and changes of physiological characteristics related to stress tolerance were due to the overexpressing of FALDH in tobacco.