Seasonality and longer-term development generate temporal dynamics in the Populus microbiome

Area of Science:

• Microbial Ecology
• Plant Science
• Ecology

Background:

• Understanding temporal dynamics of microbial communities is crucial for plant health.
• Controls over temporal variation in tree microbiomes, especially for long-lived species, are not well understood.
• Tree microbiomes may fluctuate seasonally or change over longer periods as trees age.

Purpose of the Study:

• To investigate the drivers of temporal variation in tree microbiomes.
• To differentiate between seasonal (intra-annual) and longer-term (multi-year) changes in tree-associated microbial communities.
• To analyze bacterial, archaeal, and fungal communities in poplar (Populus spp.) over time.

Main Methods:

• Utilized a common garden experiment with clonally propagated poplar plants.
• Employed amplicon sequencing to characterize microbial communities.
• Sampled leaf endosphere, root endosphere, and rhizosphere across four seasons over two consecutive years.

Main Results:

• Microbial community composition varied significantly among seasons and years.
• Seasonal and yearly variations accounted for up to 21% of the total variation in microbial community composition.
• Microbial community dissimilarity increased over time, indicating longer-term compositional shifts as host trees aged, and correlated with climatic conditions.

Conclusions:

• Temporal patterns in tree microbiomes result from an interplay between seasonal fluctuations and longer-term developmental changes.
• Seasonal microbiome patterns are not static but evolve year-to-year due to host aging.
• Future studies on tree microbiomes should incorporate background temporal dynamics to accurately assess spatial patterns and responses to environmental changes.