The microbiome composition of protocorms in the terrestrial orchid Gymnadenia conopsea.

The process of orchid protocorm formation during the early stages of symbiotic germination can be classified into five distinct phases: stage 1(A), stage 2(B), stage 3(C), stage 4(D), and stage 5(E). However, there is a scarcity of literature documenting the dynamics of microbial communities within the protocorm at different germination stages. We conducted amplicon sequencing targeting bacterial and fungal regions to investigate the changes in the endophytic microbiome community during different germination stages of Gymnadenia conopsea protocorms under in situ symbiosis. The full-length 16S rRNA sequences amplified by 27F and 1492R primers were selected as bacterial amplicon regions for subsequent sequencing. The fungal amplicons were selected as the ITS2 regions amplified using ITS86F and ITS4 primers.