TraeALDH7B1-5A, encoding aldehyde dehydrogenase 7 in wheat, confers improved drought tolerance in Arabidopsis
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TraeALDH7B1 - 5A , encoding aldehyde dehydrogenase 7 in wheat, conferred significant drought tolerance to Arabidopsis , supported by molecular biological and physiological experiments.
Drought stress significantly affects wheat yields. Aldehyde dehydrogenase (ALDH) is a family of enzymes catalyzing the irreversible conversion of aldehydes into acids to decrease the damage caused by abiotic stresses. However, no wheat ALDH member has been functionally characterized to date. Here, we obtained a differentially expressed EST encoding ALDH7 from a cDNA-AFLP library of wheat that was treated with polyethylene glycol 6000. The three full-length homologs of TraeALDH7B1 were isolated by searching the NCBI database and by homolog-based cloning method. Using nulli-tetrasomic lines we located them on wheat chromosomes 5A, 5B and 5D, and named them as TraeALDH7B1-5A, -5B and -5D, respectively. Gene expression profiles indicated that the expressions of all three genes were induced in roots, leaves, culms and spikelets under drought and salt stresses. Enzymatic activity analysis showed that TraeALDH7B1-5A had acetaldehyde dehydrogenase activity. For further functional analysis, we developed transgenic Arabidopsis lines overexpressing TraeALDH7B1-5A driven by the cauliflower mosaic virus 35S promoter. Compared with wild type Arabidopsis, 35S::TraeALDH7B1-5A plants significantly enhanced the tolerance to drought stress, which was demonstrated by up-regulation of stress responsive genes and physiological evidence of primary root length, maintenance of water retention and contents of chlorophyll and MDA. The combined results indicated that TraeALDH7B1-5A is an important drought responsive gene for genetic transformation to improve drought tolerance in crops.
KeywordsAldehyde dehydrogenase Drought tolerance Common wheat Arabidopsis
Amplified fragment length polymorphism
Days after sowing
Days after rewatering
Expressed sequence tag
Nicotinamide-adenine dinucleotide phosphate
We thank the expertise of Miss Shuang Fang and Dr. Jinfang Chu (National Centre for Plant Gene Research (Beijing), Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China) in determining the ABA contents of the plant materials. We thank Professor Robert A. McIntosh (Plant Breeding Institute, University of Sydney, NSW, Australia) for revising the manuscript and constructive advice. The project was sponsored by National Natural Science Foundation of China (31101141) and National Key Technology R & D Program (2011BAD07B00).
Conflict of interest
The authors have no conflicts of interest to declare.
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