(2008) who stated that the presence of dominant Badh2 allele encoding Betaine Aldehyde Dehydrogenase (BADH2) inhibited synthesis of 2AP, while its recessive alleles induced 2AP formation.
Badh2, encoding betaine aldehyde dehydrogenase, inhibits the biosynthesis of 2-Acetyl-1-pyrroline, a major component in rice fragrance.
The cDNA fragment Musa 26 encodes betaine aldehyde protein dehydrogenase (BADH, EC 126.96.36.199), enzyme that catalyzes the oxidation of betaine aldehyde to glycine betaine (GB).
cDNA Best homology Organism Identity of fragment to database aminoacid (%) Musa 07 putative Na+/H+ Arabidopsis thaliana 85 antiporter SOS1 Musa 10 cytosolic ascorbate Vigna unguiculata 81 peroxidase Musa 23 serine/threonine Arabidopsis thaliana 73 protein kinase SOS2 Musa 26 betaine aldehyde Suaeda liaotungensis 72 dehydrogenase (BADH) * Of the sequences obtained, four exhibited a high degree of similarity to amino acids sequence of genes whose functions are already known, nine displayed low similarity, and ten sequences were not similar
Betaine is synthesized by a two-step oxidation of choline in which mitochondrial choline oxidase first catalyzes the production of betaine aldehyde
, which is further oxidized by mitochondrial betaine aldehyde
dehydrogenase to betaine (Dragolovich, 1994).
coli choline dehydrogenase tobacco (betA) and betaine aldehyde
dehydrogenase (betB) genes Atripler hortensis betaine aldehyde
wheat (Triticum aestivum L.) dehydrogenase (BADH) gene under maize ubiquitin promoter Barley peroxisomal BADH gene rice Proline Vigna aconitifolia L.
An alternative metabolic route for choline is oxidation to Betaine, catalyzed by the sequential action of choline oxidase (EC 188.8.131.52) and Betaine aldehyde
dehydrogenase (EC 184.108.40.206).
The Suaeda liaotungensis kitag betaine aldehyde
dehydrogenase gene improves salt tolerance of transgenic maize mediated with minimum linear length of DNA fragment.
GB nonaccumulation appears to be caused by recessive alleles of a single locus in maize (Rhodes and Rich, 1988; Rhodes et al., 1989) that results in an inability to convert choline to betaine aldehyde
, the first committed step in the synthesis of GB (Lerma et al., 1991).
An important metabolic pathway for choline involves its conversion into glycine via betaine aldehyde
, betaine, N,N-dimethylglycine (DMG)  and sarcosine (Fig.
ORF1 (TMABaldehyde-DH), which encodes 496 amino acids also shares identity with betaine aldehyde
dehydrgenase of Pseudomonas aeruginosa, TMABaldehyde-DH of rat liver (Fig.
Rice does not accumulate glycine betaine as does barley and other plants (Ishitani et al., 1993) because of a deficiency in choline monooxygenase and betaine aldehyde
dehydrogenase (Rathinasabapathi et al., 1993).