Fig. 2
Nematostella populations from different climatic conditions respond differently to heat stress. a Distribution of Nematostella populations along the East coast of North America. b Average high July (red) and average low January (blue) temperatures across the populations from the North to the South. The data originate from publicly available sources (https://www.usclimatedata.com/climate, https://en.climate-data.org/north-america/) for the cities closest to the sampling points (Halifax, NS; Portland, ME; Manchester, NH; New Bedford, MA; Wilmington, NC). Solid line—control temperature (20 °C), dashed line—heat stress temperature (36 °C) used in our experiments. c, d Gene expression dynamics under heat stress (+ 36 °C) (c) and low salinity stress (5 ‰) (d) among the populations from the North to the South (Additional file 3: Table S1). If the change in expression of a gene is greater than 2.4 times and p < 0.05 (Student’s t test), the corresponding data point is outlined in bold and labeled by a red asterisk. Only genes with expression change (increase or decrease) higher than 2.4-fold and with statistically significant (p < 0.05, Student’s t test) difference between control and treatment in at least two populations are shown. Error bars represent standard deviations accounting for error propagation of the treatment/control ratios. e, f Expression of toxins in Massachusetts (e) and North Carolina (f) following heat stress. Gene expression is represented as Log10 of normalized fluorescence units measured by nCounter technology (Additional file 3: Table S1). p values calculated by Student’s t test are shown for each gene. If the change in expression of a gene is greater than 2.4 times and p < 0.05, the corresponding p value is shown in red. Error bars represent standard deviations