Figure 5

CFKs contribute to plant adaptation evolution. (A) Phylogeny and number of species among the lineages of green plants adapted from⁵⁴. (B) The B5 CFKs receive low frequency CS and originated in charophytes, with functions dates back to charophyte alga-fungi symbiosis reported by⁵⁵. (C) The high frequency CS that some B5 CFKs receive³⁶. This group of genes shows myristoylation, palmitoylation, and acylation at the N-terminal and originated in charophyte, and act in the salt, drought, and pathogen stress signalling pathways. (D) The loss of auto-inhibitory domain (AID) and calmodulin-like domain (CaM-LD) of B6 genes caused these genes not activated by calcium. Both genes and crassulacean acid metabolism (CAM) originated in lycophytes whereas C4 photosynthesis was only found in angiosperms⁵⁶. (E) This C3 subgroup of CFKs originated in the gymnosperm genomes. The loss of the EF hands also caused these genes not activated by calcium. Their roles in seed maturation development were found in seed plants. (F) The moderate frequency CS that some B5 CFKs receive. These genes have N-terminal myristoylation and palmitoylation and originated in charophytes. Their roles in male gamete maturation were confirmed in grapevine³⁸, rice⁵⁷, A. thaliana and P. patens. Capital letter in the triangle: gene group and its typical gene structure, small letter in the triangle: characterized gene functions. Solid vertical green bar: phylogenetic clade where genes are present; dotted vertical line indicates possible functions in these clades, and the solid blue bar in the dotted vertical line indicates species where gene functions have been validated.