A novel cold-regulated protein isolated from Saussurea involucrata confers cold and drought tolerance in transgenic tobacco (Nicotiana tabacum)

Abstract

Adverse environmental conditions, such as cold and drought, can inhibit plant growth, development, and productivity. The isolation and characterization of stress response genes from stress-tolerant plants can provide a better understanding of the underlying adaptive mechanisms. In this study, a novel cold-regulated gene, SikCOR413PM1, was isolated from Saussurea involucrata Kar. et Kir., which is a plant that survives at the high altitudes and in the low temperatures of alpine slopes in northwestern China. SikCOR413PM1 was induced in response to cold and drought in S. involucrata, and phylogenetic analysis revealed that the gene groups with a COR gene encoding a COR413PM protein family member. Subcellular localization of a SikCOR413PM1-green fluorescent fusion protein showed that SikCOR413PM1 was localized to the plasma membrane. A transgenic tobacco (Nicotiana tabacum) system was employed to investigate the possible role of SikCOR413PM1 in cold and drought tolerance. Analyses of growth, germination and survival rates, relative water content, malondialdehyde content, relative electrolyte leakage, and maximal photochemical efficiency of photosystem II showed that transgenic tobacco plants expressing SikCOR413PM1 were more tolerant to cold and drought stresses than WT plants. SikCOR413PM1 overexpression was also accompanied by constitutive activation of NtDREB1 and NtDREB3, two cold-responsive transcription factor genes, and NtERD10A and NtERD10B, two cold-induced genes. The expression levels of downstream transcription factor genes NtDREB3, NtERD10C, NtERD10D, and NtLEA5 were also induced in SikCOR413PM1-expressing transgenic plants under drought conditions. Our results suggest that the overexpression of SikCOR413PM1 induces changes in tobacco plants, and facilitates enhanced tolerance to cold and drought stresses.