Stress-inducible expression of a Cleistogenes songorica ALDH gene enhanced drought tolerance in transgenic Arabidopsis thaliana

摘要

Aldehyde dehydrogenases (ALDHs) have been considered as general detoxifying enzymes which eliminate abiotic stress in a variety of organisms. The ALDH12A participates in preventing proline toxicity. To targeted mining drought responsive genes from Cleistogenes songorica, a xerophytic grass distributed in the arid-desert grasslands of Inner Mongolia China, cDNA libraries from leaves and roots of drought-stressed seedlings were constructed. Here, we cloned an ALDH12A homologue, CsALDH12A1 (GenBank No. FJ972824). The CsALDH12A1 cDNA is 2,016 bp and encodes a deduced polypeptide of 551 amino acids, approximately 93% identical to the Sorghum bicolor homologue. Quantitative RT-PCR was conducted to examine the expression pattern. The results showed that CsALDH12A1 transcripts accumulated a six-fold abundance in response to drought stress. Furthermore, transgenic Arabidopsis plants expressing CsALDH12A1 under the abiotic stress inducible rd29A promoter showed enhanced tolerance to drought stresses. The Malondialdehyde (MDA) content of the transgenic plants with rd29A::CsALDH12A1 were significantly lower (P<0.01) than that in non-transgenic plants, which confirm the crucial role of ALDH12A1 in the detoxification of reactive aldehydes produced from lipid per-oxidation. The data presented here suggest that CsALDH12A1 plays a crucial role in abiotic stress tolerance during plant development.