Requirement for Different Normalization Genes for Quantitative Gene Expression Analysis Under Abiotic Stress Conditions in ‘Bangia’ sp. ESS1

Quantitative gene expression analysis is indispensable for accurately characterizing the expression levels of genes involved in the response and acclimation of algae to environmental stresses.However, appropriate reference genes in the genus Bangia (order Bangiales) for quantification of stress-inducible gene expression are not well described.Thus, we evaluated the suitability of genes encoding 18S ribosomal RNA (18S rRNA), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), actin, tubulin, elongation factor 1 (EF1), and 60S ribosomal RNA (60S rRNA) as reference genes for real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) under various stress conditions in 'Bangia' sp.ESS1, classified into the 'Bangia' 2 group.Our results showed that the 60S rRNA and GAPDH genes were most suitable for gene expression analyses in response to nutrient deficiency, high salinity, and temperature stress, whereas normalization of desiccation-inducible expression required use of the EF1 and tubulin genes.These findings indicate that reference genes for analysis of stress-inducible gene expression by qRT-PCR should be selected according to the environmental stress being studied.Our efforts to identify easily amplified reference genes for various stress responses provide novel insights into the selection of reference genes for seaweeds.