Cloning And Expression Of The Betaine Synthetase Genes From Ophiopogon Japonicus

Betaine is a very effective innocuous osmopretectant existed in many organisms. Its importance is acknowledged. Ophiopogon japonicus is a perennial evergreen grass with high stress tolerance ability. This research performed a study on the genes betaine synthetase in Ophiopogon japonicus.1. The full length BADH and CMO cDNA were obtained from Ophiopogon japonicus(L.F)Ker-Gawl by RT-PCR and RACE.2. BADH cDNA (1785bp) included a 63 bp 5 'UTR, a 219 bp 3 'UTR and a 1503 bp ORF encoding a 500-amino-acid polypeptide which showed closely similar sequence identity to BADH from Chenopodiaceae. By BLAST, the deduced amino acid sequence included conserved domains of aldehyde dehydrogenase family, NAD-dependent aldehyde dehydrogenases, Delta 1-pyrroline-5-carboxylate dehydrogenase etc.3. CMO cDNA (1602 bp) included a 54 bp 5 'UTR, a 231 bp 3 'UTR and a 1317 bp ORF encoding a 438-amino-acid polypeptide which showed closely similar sequence identity to CMO from Chenopodiaceae. By BLAST, the deduced amino acid sequence included the conserved domains of [2Fe-2S] domain, Fe-binding motif, Ferredoxin subunits of nitrite reductase, etc4. The BADH and CMO ORF were obtained and the plant expression vector pCU1303-BADH, pCU1303-CMO were constructed.5. Analysis of mRNA levels by Northen bloting indicated that the expression of BADH and CMO in Ophiopogon japonicus leaves were higher than CK after being treated with 1% NaCl stress for different hours and being treated with low temperature stress for different days.