Molecular cloning and characterization of a novel soybean gene encoding a leucine-zipper-like protein induced to salt stress

• Published in: Gene 2005-08, Vol.356, p.135-145
• Main Authors: Aoki, Ayako, Kanegami, Akemi, Mihara, Michiko, Kojima, Toshio, Shiraiwa, Masakazu, Takahara, Hidenari
• Format: Article
• Language: English
• Subjects: Abscisic Acid - pharmacology; Amino Acid Sequence; Base Sequence; Blotting, Northern; cDNA-AFLP; Cloning, Molecular; Dehydration; DNA, Complementary - chemistry; DNA, Complementary - genetics; Gene expression; Gene Expression Regulation, Plant - drug effects; Genes, Plant - genetics; Glycine max; Glycine max - drug effects; Glycine max - genetics; Glycine max [L.] Merr; GmTDF; Hydrophobic and Hydrophilic Interactions; Mannitol - pharmacology; Molecular Sequence Data; Plant Leaves - drug effects; Plant Leaves - genetics; Plant Roots - drug effects; Plant Roots - genetics; Plant Stems - drug effects; RNA, Messenger - genetics; RNA, Messenger - metabolism; Salicylic Acid - pharmacology; Sequence Analysis, DNA; Sodium Chloride - pharmacology; Soil salinity; Soybean Proteins - chemistry; Soybean Proteins - genetics
• ISSN: 0378-1119; 1879-0038
• DOI: 10.1016/j.gene.2005.04.014

To understand molecular responses to salt stress in soybean ( Glycine max [L.] Merr.), we identified 106 salt-inducible soybean genes that expressed differentially at 72 h after 100 mM NaCl treatment using the cDNA-amplified fragment length polymorphism (AFLP) method. The genes were designated as G. max Transcript-Derived Fragments ( GmTDFs). Among these genes, we characterized a soybean gene GmTDF-5 that encoded an unknown protein of 367 amino acids. The GmTDF-5 protein was a putative cytosolic protein with two leucine-zipper motifs at the N-terminal and was calculated as 40.7 kDa. Southern blot analysis indicated that GmTDF-5 presents as an intron-less single gene on soybean genome and possibly distributes narrowly throughout the higher plants. By 100 mM NaCl treatment, the gene expression of GmTDF-5 was induced in the stem and lower-expanded leaf, and the amount of mRNA increased 5.1- and 2.0-fold up to 72 h, respectively. Interestingly, GmTDF-5 expression in the upper-leaf appeared dramatically with 10.0-fold increase at 72 h after the salt stress, but not until 48 h. Hyperosmotic pressure (mannitol treatment) and dehydration also caused the increases similar to NaCl treatment in the levels of GmTDF-5 expression. These results suggest that GmTDF-5 might be a novel cytosolic leucine-zipper-like protein functioning in mature organs of soybean shoot against water-potential changes.