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The calcineurin B-like (CBL) proteins, comprising a large subfamily of calcium sensors in plant cells, play an important role in many stress responses. We cloned a gene from the halophyte Thellungiella halophila that is homologous to AtCBL9 in Arabidopsis thaliana. The 1008-bp ThCBL9 contains an ORF of 639 bp and encodes 213 amino acids, with a 5“-untranslated region of 193 bp and a 3”-untranslated region of 176 bp. Its amino acid sequence shares high homology with AtCBLs. ThCBL9 is up-regulated by ABA, NaCI, and PEG in Thellungiella leaves. Using molecular biological methods, we over-expressed ThCBL9 in A. thaliana and found that this enhanced tolerances to both high salt and osmotic stress in transgenic Arabidopsis. [ABSTRACT FROM AUTHOR]

Abstract: Galactinol synthase (GOLS, EC 2.4.1.123), a key enzyme in the synthesis of raffinose family oligosaccharides (RFOs), catalyzes the condensation of UDP-galactose with myo-inositol to produce galactinol as the sole donor for the synthesis of RFOs. RFOs have been implicated in mitigating effects of environmental stresses on plants. TsGOLS2, was cloned from Thellungiella salsuginea with high homology to AtGOLS2. TsGOLS2 was up-regulated by several abiotic stresses. We overexpressed TsGOLS2 in Arabidopsis thaliana. The contents of galactinol, raffinose, and α-ketoglutaric acid were significantly increased in transgenic plants. Compared to wild type plants, salt-stressed transgenic A. thaliana exhibited higher germination rate, photosynthesis ability, and seedling growth. After being treated with osmotic stress by high concentration of sorbitol, transgenic plants retained high germination rates and grew well during early development. These results indicated that overexpression of TsGOLS2 in A. thaliana improved the tolerance of transgenic plants to high salinity and osmotic stress. [Copyright &y& Elsevier]