A comparison for formaldehyde detoxification capacity on transgenic tobacco over-expressing the FALDH from Arabidopsis and the fused HPS/PHI from Mycobacterium gastri MB19

Abstract

The cDNA for glutathione-dependent formaldehyde (HCHO) dehydrogenase (FALDH) from Arabidopsis and the fused gene for 3-hexulose-6-P synthase (HPS) and 6-phospho-3-hexuloisomerase (PHI) from a methylotrophic bacterium, Mycobacterium gastri MB19, were over-expressed in tobacco, respectively under the control of tomato rbcS-3C promoter. The FALDH and the fused HPS/PHI were expressed in the cytoplasm and chloroplasts, respectively in the transgenic tobacco. Our assay indicated that overexpression of the FALDH gene and the fused HPS/PHI gene led to an increase in FALDH and HPS/PHI activities in the two transgenic tobacco plants, respectively. The transgenic tobacco overexpressing fused HPS/PHI (HPS/PHI tobacco) showed higher tolerance to HCHO than the transgenic tobacco over-expressing FALDH (FALDH tobacco) when they were grown on MS medium with HCHO or treated with gaseous HCHO. Our measurement also suggested that the HPS/PHI tobacco had stronger ability for HCHO detoxification than FALDH tobacco.