Identification and Isolation of Differentially Expressed Gene in Response to Cold Stress in a Green Alga, Spirogyra varians (Zygnematales)

doi:2007.22.2.131

Algae > Volume 22(2); 2007 > Article

Algae 2007;22(2): 131-139. doi: https://doi.org/10.4490/algae.2007.22.2.131

Jong Won Han¹, Minchul Yoon², Key Pyoung Lee¹ and Gwang Hoon Kim²^*

¹Department of Chemistry, Kongju National University, Kongju, 314-701, Korea
²Department of Biology, Kongju National University, Kongju, 314-701, Korea

ABSTRACT

The expression of genes responding to cold stress in a freshwater alga, Spirogyra varians, was studied by using differential expression gene (DEG) method. A gene strongly up-regulated in 4°C was isolated and designated as SVCR2 (Spirogyra varians cold regulated) gene. The cDNA encoding SVCR2 was cloned using λZAP cDNA library of Spirogyra varians. The deduced amino acid had a sequence similarity with trans-membrane protein in Arabidopsis thaliana (Q9M2D2, 52.7%). Northern blot analysis demonstrated that transcript level of SVCR2 increased about 10 fold under low temperature (4°C), compared with that cultured at warm (20°C) conditions. The expression of SVCR2 was also affected by light conditions. When the plants were exposed to high light (HL) (1200 μmol photon m?2 s?1), the expression of SVCR2 began within 2 hrs. This gene expression lasted for 4 hrs and decreased afterwards. Under the blue light (470 nm) condition, the expression of this gene was induced in same way as HL treatment, even under less than 100 μmol photon m?2 s?1. But red light (650 nm) and UV-A irradiation did not affect the expression of SVCR2.

Key words: cold stress, differentially expressed gene (DEG), Spirogyra varians