Figure 2. Differential expression of Hydra genes under influence of Chlorella photosynthesis.

(A) Sampling scheme. Hv_Sym (green) and Hv_Apo (orange) were cultured under a standard light-dark regime (Light: L) and in continuous darkness (Dark: D), and RNA was extracted from the polyps at the days indicated by red arrows. (B) Expression difference of five A99-specific genes in Hv_Sym (green bars) and Hv_Apo (orange bars) between the light-dark condition and darkness. The vertical axis shows log scale (log2) fold changes of relative expression level in Light over Dark. (C) Sampling scheme of inhibiting photosynthesis. (D) Differential expression of the five A99-specific genes under conditions allowing (Control) or inhibiting photosynthesis (DCMU). The vertical axis shows log scale (log2) fold changes of relative expression level in Control over DCMU treated. T-tests were performed between Light and Dark (B), and DCMU and Control (D). For each biological replicate (n = 3) 50 hydra polyps were used for total RNA extraction. Error bars indicate standard deviation. P-value of t-test, *<0.05, **<0.01.

Figure 2—figure supplement 1. Differential expression of symbiosis-dependent Hydra genes grown under light/dark condition and in darkness.

(A) Sampling scheme. Hv_Sym was cultured in the light-dark condition (Light: L) and in the continuous dark (Dark: D). Gene expression levels were examined by qPCR at 1, 2, 4 days for each condition (red arrows). (B) Expression difference of the genes in Hv_A99 between the two conditions. DEATH-1 and DEATH-2: Death domain containing proteins (gene ID: 6508 and rc_2417), TIR: Toll/interleukin-1 receptor domain containing protein (gene ID: 5168), PRKRIR: protein-kinase interferon-inducible double stranded RNA dependent inhibitor, repressor of (p58 repressor) (gene ID: rc_9398), ephrinR: ephrin receptor (gene ID: 26108), CLEC: C-type mannose receptor (gene ID: 11411), PRRT1: proline-rich transmembrane protein 1 (gene ID: rc_24563). For each biological replicate (n = 3) 50 hydra polyps were used for total RNA extraction. The vertical axis shows log scale (log2) fold change of relative expression levels in the light condition over the dark condition. Error bars indicate standard deviation. Pvalue of t-test, *<0.05, **<0.01.