Analysis of Growth Responses in Saccharina latissima Gametophytes in Different Nutrient Solutions and Profiling of Peroxidases in Sporophytes under Light Stress.

Saccharina latissima a brown sugar kelp is a highly nutritional seaweed, grows well in the Norwegian climate and can be used as food and feed. Different research studies were conducted to find the optimal nutritional content and environmental conditions that promoted the growth. The current study is designed with two important but different aims: the first study is designed to test the impact of three different nutrient solutions (i.e. ½ PES (Provasoli Enriched seawater), F/2 (Guillard Marine Enrichment medium), and ES(Enriched Seawater) based on nutritional value) on the growth of S. latissima gametophytes under red light stress conditions; the second study is done to understand the regulation of gene expression in response to light intensity stress stimuli in S. latissima sporophyte stage by taking a holistic approach to uncover the intricate relationship between peroxidase genes and environmental stimuli in S. latissima. In first study, 1/2 PES and F/2 came out to be nutrient rich that promoted the growth of S. latissima whereas ES showed minimal impact on growth, regarded as nutrient deficient. These results imply that nutrient rich solutions can be used to promote the growth of kelp. In second study, different peroxidase genes showed different expression under three different red-light intensities. Most of the heme and non-heme peroxidase genes e.g. Apx01, NAnprx Cp03, showed upregulation under medium and maximum red intensity level 1000 μmol m-2 s-1and 250 μmol m-2 s-1 respectively. While some peroxidase genes Ccp0,Cp04 and Pxd04 showed downregulation at medium and maximum red-light intensity 100 μmol m-2 s-1 and 250 μmol m-2 s-1 respectively, suggested a fine-tuned cellular response, indicating an adaptive mechanism for protection against light stress in the sporophyte. Further studies are recommended to analyze the underling mechanism in short duration experiments. Overall, our research shows growth and gene regulation is highly influenced by external factors like light and temperature.