Overexpression of a stress‐inducible aldehyde dehydrogenase gene from Arabidopsis thaliana in transgenic plants improves stress tolerance

Abstract

SummaryIn plants, oxidative stress is one of the major causes of damage as a result of various environmental stresses. Oxidative stress is primarily because of the excessive accumulation of reactive oxygen species (ROS). The ampli®cation of ROS damage is further stimulated by the accumulation of toxic degradation products, i.e. aldehydes, arising from reactions of ROS with lipids and proteins. Previously, the isolation of dehydration-inducible genes encoding aldehyde dehydrogenases (ALDHs) was reported from the desiccation-tolerant plant Craterostigma plantagineum and Arabidopsis thaliana. ALDHs belong to a family of NAD(P) -dependent enzymes with a broad substrate speci®city that catalyze the oxidation of various toxic aldehydes to carboxylic acids. Analysis of transcript accumulation revealed that Ath-ALDH3 is induced in response to NaCl, heavy metals (Cu 2 and Cd 2 ), and chemicals that induce oxidative stress (methyl viologen (MV) and H 2 O 2 ). To investigate the physiological role and possible involvement of ALDHs in stress protection, we generated transgenic Arabidopsis plants overexpressing Ath-ALDH3. Transgenic lines show improved tolerance when exposed to dehydration, NaCl, heavy metals (Cu 2 and Cd 2 ), MV, and H 2 O 2 . Tolerance of transgenic plants is correlated with decreased accumulation of lipid peroxidation-derived reactive aldehydes (as measured by malondialdehyde) compared to wild-type plants. Increased activity of Ath-ALDH3 appears to constitute a detoxi®cation mechanism that limits aldehyde accumulation and oxidative stress, thus revealing a novel pathway of detoxi®cation in plants. We suggest that Ath-ALDH3 could be used to obtain plants with tolerance to diverse environmental stresses.

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

“…MDA is an end product of polyunsaturated fatty acid oxygenation and is a commonly used biomarker for assessing lipid peroxidation (Janero 1990;Moore and Roberts 1998). In plant cells, environmental stressors, such as drought, salinity, extreme temperatures and heavy metals, cause a rapid and excessive accumulation of reactive oxygen species that further cause lipid peroxidation (Sunkar et al 2003). The levels of lipid peroxidation in plant cells were assayed with the thiobarbituric acid test, which determines the amounts of MDA as end product of lipid peroxidation (Heath and Packer 1968;Loreto and Velikova 2001;Sunkar et al 2003).…”

“…In plant cells, environmental stressors, such as drought, salinity, extreme temperatures and heavy metals, cause a rapid and excessive accumulation of reactive oxygen species that further cause lipid peroxidation (Sunkar et al 2003). The levels of lipid peroxidation in plant cells were assayed with the thiobarbituric acid test, which determines the amounts of MDA as end product of lipid peroxidation (Heath and Packer 1968;Loreto and Velikova 2001;Sunkar et al 2003). A recent study also demonstrated that the reduced levels of MDA accumulation were correlated with the elevated stress tolerance in the transgenic overexpressors of several Arabidopsis ALDH genes (Kotchoni et al 2006).…”

“…The root length and fresh weight were measured after 35 days. Meanwhile, measurements of lipid peroxidation were performed with the thiobarbituric acid (TBA) test, which determines malondialdehyde (MDA) as an end product of lipid peroxidation (Sunkar et al 2003).…”

“…In Arabidopsis, several ALDHs have been described to be involved in stress tolerance. The Arabidopsis ALDH3I1 and ALDH3H1 encode aldehyde dehydrogenases homologous to class-3 ALDHs (Kirch et al 2001) and transgenic Arabidopsis plants over-expressing ALDH3I1 shows improved tolerance to diverse environmental stresses (Sunkar et al 2003). A mitochondria-localized ALDH5F1 encodes a succinic semialdehyde dehydrogenase and constitutes a member of the c-aminobutyric acid shunt in Arabidopsis (Busch and Fromm 1999).…”

Transcriptome differences between fiber-type and seed-type Cannabis sativa variety exposed to salinity

“…Stress can lead to the accumulation of toxic degradation products, including aldehydes (Srivastava et al 2002). The overexpression of aldehyde dehydrogenase genes (ALDHs) from A. thaliana catalyzed the dehydrogenation of aldehydes and enhanced the salt tolerance of transgenic plants (Sunkar et al 2003). Thus it is clear that in terms of the response of industrial hemp to salt stress, small molecule metabolism pathways deserve our attention.…”