Development of the rice coral Montipora capitata.

(A) Montipora capitata colony. (Ba to Bf) Brightfield images of M.capitata embryos collected at different developmental stages. Scale bar, 1mm. (Ca to Cf) Confocal images of M.capitata embryos at different developmental stages. Green, alpha-tubulin; Magenta, algal autofluorescence. Scale bar, 800 μm. Asterisks indicate the oral end. (Da to De) Oral view of segment formation during polyp development. Top panel, bright field images; bottom panel, cartoon diagrams. Segment IDs are assigned based on their order of emergence and size.

The genomic arrangement and temporal expression patterns of M.capitata Hox-Gbx genes.

(A) Macrosynteny of homeobox containing genes between Nematostella and M.capitata. M.capitata scaffolds and their corresponding Nematostella chromosomes are connected via colored ribbons. (B) Genomic arrangement of the Hox cluster between the two species. (C) Hox-Gbx expression during M.capitata developmental time course.

The spatial expression patterns of M.capitata Hox-Gbx genes.

(A-F) Expression of McAnthox8. (G-L) Expression of McAnthox6a.1. (M-R) Expression of McGbx. (S-X) Expression of McAnthox1.

Chemical inhibition of the BMP signaling pathway results in segmentation defects in Montipora capitata.

(A) Diagram illustrating the key components of the canonical BMP signaling pathway. Chemical inhibitors Dorsomorphin and LDN-193189 specifically target type I BMP receptor and block the activation of downstream target genes including the Hox-Gbx complex. (B) Diagram of inhibitor treatment. Both inhibitors were administered on to 4dpf larvae for 2 days prior to settlement induction using Hym-248. The morphology of settled spats as well as the percentage of settlement was documented on day 8. (C) Representative brightfield images of coral spats after DMSO, Dorsomorphin and LDN-193189 treatment. Scale bar, 1mm. (D) Percentage of larvae that settled under different treatment conditions. (E) Oral view of DMSO treated settler. (F) Oral view of Dorsomorphin treated settler. Scale bar, 100μm. (G) Expression heatmap of BMP components and their downstream targets in DMSO, Dorsomorphin and LDN-193189 treated larvae 2 days after settlement induction.

Heterochrony of segmentation sequence between Montipora capitata and Nematostella vectensis.

(A) Schematics demonstrating the sequence of segment formation between the two Anthozoan species.