[Cloning of E. coli mtl-D gene and its expression in transgenic Balizhuangyang (Populus)]

E. coli 1-phosphate mannitol dehydrogenase gene (mtl-D) was cloned using PCR method. Sequence analysis showed that the gene was the same as the published one except that codon CAT at position 416 was replaced by AAA and resulted in a Lys residue instead of His. This gene (mtl-D) was inserted in a binary vector and transformed into populas via agrobacteria. Several transgenic plants grow very well in 0.6% NaCl while controls can not survive even in 0.4% NaCl. PCR analysis and Northern blotting indicated that foreign gene was integrated into the genome of transgenic plant and transcribed successfully.