Elevation shapes the seed endophytic bacteria richness and composition of Taraxacum officinale

Taraxacum officinale, a widely invasive plant species in New Zealand, thrives across environments, yet little is known about the seed endophytic microbial communities contributing to its adaptability. In this study, we characterized the bacterial community within T. officinale seeds across an elevation gradient of 10 to 720 meters above sea level. Using PCR-DGGE fingerprinting and 16S rRNA gene sequencing, we characterized bacterial community structures and assessed variations across sites. Bacterial richness declined significantly with increasing elevation, accompanied by distinct shifts in community composition. Non-metric multidimensional scaling revealed clear clustering of communities according to elevation, with higher elevation sites exhibiting more similar and less diverse microbiomes compared to lower elevation locations. A total of six dominant bacterial genera were identified: Pseudomonas, Streptomyces, Clavibacter, Xanthomonas, Stenotrophomonas, and Erwinia. These included core genera detected across sites and location-specific genera associated with particular elevations. These results suggested that elevation acts as an environmental filter shaping seed microbiome assembly, with potential implications for microbial transmission and plant adaptation. The functional consequences of these shifts for plant performance, adaptation, and invasion success remain unknown and require further investigation.