Expression of the betaine aldehyde dehydrogenase gene in barley in response to osmotic stress and abscisic acid

Abstract

When subjected to salt stress or drought, some vascular plants such as barley respond with an increased accumulation of the osmoprotectant glycine betaine (betaine), being the last step of betaine synthesis catalyzed by betaine aldehyde dehydrogenase (BADH). We report here cloning and characterization of BADH cDNA from barley, a monocot, and the expression pattern of a BADH transcript. An open reading frame of 1515 bp encoded a protein which showed high homology to BADH enzymes present in other plants (spinach and sugar-beet) and in Escherichia coli. Transgenic tobacco plants harboring the clone expressed high levels of both BADH protein and its enzymatic activity. Northern blot analyses indicated that BADH mRNA levels increased almost 8-fold and 2-fold, respectively, in leaves and roots of barley plants grown in high-salt conditions, and that these levels decreased upon release of the stress, whereas they did not decrease under continuous salt stress. BADH transcripts also accumulate in response to water stress or drought, indicating a common response of the plant to osmotic changes that affect its water status. The addition of abscisic acid (ABA) to plants during growth also increased the levels of BADH transcripts dramatically, although the response was delayed when compared to that found for salt-stressed plants. Removal of plant roots before transferring the plants to high-salt conditions reduced only slightly the accumulation of BADH transcripts in the leaves.

Isolation of a choline monooxygenase cDNA clone from Amaranthus tricolor and its expressions under stress conditions

“…It is well documented that ABA is an essential mediator in plant response to environmental stresses [25]. ABA and drought treatments can trigger an increase in BADH mRNA levels and the content of BADH protein in barley leaves at low temperature, but the results showed a low level accumulation of GB [12], [26]. Naidu et al [27] reported that concentration of accumulated betaine in cold-stressed wheat seedlings increased more than doubled in the controls.…”

“…CMO was assumed to be unique among plant oxygenases [6], [8]. The second step of GB synthesis is mediated by betaine aldehyde dehydrogenase (BADH) [1], which has been well documented in amaranth [2], [9] and other plants [10][11][12][13][14].…”

Synthesis of the osmoprotectant glycine betaine in Bacillus subtilis: characterization of the gbsAB genes

“…The aldehyde dehydrogenase superfamily comprises seven enzymes of bacterial and plant origin with known involvement in the synthesis of the osmoprotectant glycine betaine from its precursor glycine betaine aldehyde. These are the BetB proteins from E. coli (13) and Rhizobium meliloti (41) and betaine aldehyde dehydrogenases from plants (Spinacia oleracea, Beta vulgaris, Atriplex hortensis, Sorghum bicolor, and Hordeum vulgare) involved in the cellular adaptation to salinity and drought (24,36,53,56,57). The B. subtilis enzyme exhibits 39% sequence identity to the BetB proteins from E. coli and R. meliloti.…”

Significant improvement of stress tolerance in tobacco plants by overexpressing a stress-responsive aldehyde dehydrogenase gene from maize (Zea mays)

“…Recombinant ALDH2a protein shows acetaldehyde oxidization activity in vitro, suggesting a function in plant tolerance under anaerobic conditions . Betaine aldehyde dehydrogenases (BADHs), members of the ALDH10 family, have been intensively studied for their well-documented potential against environmental stresses, such as salinity, drought and cold (Weretilnyk and Hanson 1990;McCue and Hanson 1992;Ishitani et al 1995;Wood et al 1996;Nakamura et al 1997). Generally, BADH transcription in higher plants is induced in response to osmotic stress and its defined role is to catalyze the second step reaction in a two-step oxidation of choline via an intermediate form of betaine aldehyde in the biosynthetic pathway of the osmolyte glycine betaine (Chen and Murata 2002).…”