The co-dispersal strategy of (Verrucariaceae) shapes an unusual lichen population structure.

The reproduction and dispersal strategies of lichens play a major role in shaping their population structure and photobiont diversity. Sexual reproduction, which is common, leads to high lichen genetic diversity and low photobiont selectivity. However, the lichen genus adopts a special co-dispersal model in which algal cells from the photobiont and ascospores from the mycobiont are released together into the environment. To explore the dispersal strategy impact on population structures, a total of 62 individuals and 12 related Verrucariaceae genera individuals, representing co-dispersal strategy and conventional independent dispersal mode were studied. Phylogenetic analysis revealed that , with a large-scale geographical distribution, showed an extremely high specificity of symbiotic associations with their photobiont. Furthermore, three types of group I intron at 1769 site have been found in most mycobionts, which showed a high variety of group I intron in the same insertion site even in the same species collected from one location. This study suggested that the ascospore-alga co-dispersal mode of resulted in this unusual mycobiont-photobiont relationship; also provided an evidence for the horizontal transfer of group I intron that may suggest the origin of the complexity and diversity of lichen symbiotic associations.