A new study published in Journal of Biogeography, has revealed how phyllosphere microbiome vary with altitude in mountain forests.

The phyllosphere microbiome are the tiny organisms that live on and inside plant leaves, which can have various effects on plant health, growth, and resistance to pathogens and environmental stress. 

In the new study, the researchers from the Institute of Applied Ecology of the  Chinese Academy of Sciences sampled leaves from different tree species along elevations ranging from 800 to 1950 metres. They found that the diversity of the phyllosphere microbiome decreased with increasing elevation, and different factors affected the microbes depending on where they lived: on the leaf surface (epiphytic microbes) or inside the leaf tissue (endophytic microbes). 

For epiphytic microbes, the main factor that influenced their diversity was the average annual temperature. Higher temperatures supported more diverse and abundant microbial communities on the leaf surface. 

For the diversity of endophytic microbes, however, the leaf traits of the host plant, such as leaf area, thickness, and nitrogen content, played a more important role than temperature. 

The findings of this study highlight the need to consider the effects of climate and leaf features on the phyllosphere microbiomes.