Atriplex spp. (saltbush) is known to survive extremely harsh environmental stresses such as salinity and drought. It mitigates such conditions based on specialized physiological and biochemical characteristics. Dehydrin genes (
DHNs) are considered major players in this adaptation. In this study, a
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Atriplex spp. (saltbush) is known to survive extremely harsh environmental stresses such as salinity and drought. It mitigates such conditions based on specialized physiological and biochemical characteristics. Dehydrin genes (
DHNs) are considered major players in this adaptation. In this study, a novel
DHN gene from Azrak (Jordan) saltbush was characterized along with other
Atriplex species from diverse habitats. Intronless
DHN-expressed sequence tags (495–761 bp) were successfully cloned and sequenced. Saltbush dehydrins contain one S-segment followed by three K-segments: an arrangement called SK3-type. Two substantial insertions were detected including three copies of the K2-segemnet in
A. canescens. New motif variants other than the six-serine standard were evident in the S-segment. AhaDHN1 (
A. halimus) has a cysteine residue (SSCSSS), while AgaDHN1 (
A. gardneri var. utahensis) has an isoleucine residue (SISSSS). In contrast to the conserved K1-segment, both the K2- and K3-segment showed several substitutions, particularly in AnuDHN1 (
A. nummularia). In addition, a parsimony phylogenetic tree based on homologs from related genera was constructed. The phylogenetic tree resolved DHNs for all of the investigated
Atriplex species in a superclade with an 85% bootstrap value. Nonetheless, the DHN isolated from Azraq saltbush was uniquely subclustred with a related genera
Halimione portulacoides. The characterized DHNs revealed tremendous diversification among the
Atriplex species, which opens a new venue for their functional analysis.
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