Key Lab of Plant Stress Research, Life Science College, Shandong Normal University, 88 Wenhua East Road, Jinan 250014, China.
Plant Physiol Biochem. 2013 Aug;69:82-9. doi: 10.1016/j.plaphy.2013.04.009. Epub 2013 Apr 25.
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.
半乳糖基转移酶（GOLS，EC 2.4.1.123）是合成棉子糖家族低聚糖（RFOs）的关键酶，它催化 UDP-半乳糖与肌醇缩合，产生半乳糖醇作为合成 RFOs 的唯一供体。RFOs 被认为可以减轻植物环境胁迫的影响。从盐生拟南芥中克隆出与 AtGOLS2 高度同源的 TsGOLS2。TsGOLS2 受到多种非生物胁迫的上调。我们在拟南芥中过表达了 TsGOLS2。转基因植物中半乳糖醇、棉子糖和α-酮戊二酸的含量显著增加。与野生型植物相比，盐胁迫的转基因拟南芥表现出更高的发芽率、光合作用能力和幼苗生长。在用高浓度山梨醇处理渗透胁迫后，转基因植物保持高发芽率，在早期发育过程中生长良好。这些结果表明，在拟南芥中过表达 TsGOLS2 提高了转基因植物对高盐和渗透胁迫的耐受性。
