thank you

As always, clicking past the newspaper headline and through to the research shows that it is the newsroom that introduces this confusion. Here’s the abstract, showing that the microbiome is indeed assumed and the paper is offering an initial exploration as to what precisely this microbiome consists of:

> Despite significant advances in microbiome research across various environments, the microbiome of Earth’s largest biomass reservoir—the wood of living trees—remains largely unexplored. Here, we illuminate the microbiome inhabiting and adapted to wood and further specialized to individual host tree species, revealing that wood is a harbour of biodiversity and potential key players in tree health and forest ecosystem functions. We demonstrate that a single tree hosts approximately one trillion bacteria in its woody tissues, with microbial communities distinctly partitioned between heartwood and sapwood, each maintaining unique microbiomes with minimal similarity to other plant tissues or ecosystem components. The heartwood microbiome emerges as a particularly unique ecological niche, distinguished by specialized archaea and anaerobic bacteria driving consequential biogeochemical processes. Our findings support the concept of plants as ‘holobionts’—integrated ecological units of host and associated microorganisms—with implications for tree health, disease and functionality. By characterizing the composition, structure and functions of tree internal microbiomes, our work opens up pathways for understanding tree physiology and forest ecology and establishes a new frontier in environmental microbiology.

Because on a larger scale, trees of the same species will have very specific microbiomes. In the past, most of the studies focused on ecology scales.

The headline is a little crazy. This is like someone talking about the Human Genome Project and the headline reading "scientists discover humans have DNA" The diversity at many levels was even known. They're just trying (which is great) to get far more known genomes (the same way we are doing with human microbiomes now)

Multicellular life seems to have appeared independently from unicellular life several times in the past, including 6 instances of complex multicellular life from eukaryotic cells, that led to animals and land plants. It may also have happened repeatedly, with some disappearing altogether in course of time. Another important aspect of life is the extreme prevalance of symbiosis, even among unicellular life. It's even theorized that the genesis of the entire Eukaryota domain and many of its organnelles (notably mitochondria and chloroplasts) are the results of repeated cellular endosymbiosis where a unicellular organism consumed a prokaryote that eventually becomes a useful part of the host cell instead of its food.

Considering the two facts above and how often multicellular organisms and unicellular organisms interact, it's highly improbable that any multicellular organism would have evolved without developing a life sustaining dependence on a huge array of unicellular organisms. I would be very surprised if that happened.

I'm not dismissing your remark. Any day where you don't learn at least one new thing is a day wasted. But given the mathematical odds, what you said seems inevitable to me rather than a surprise.

Supposedly they also emit ultrasonic sounds when lacking water, or getting leaves cut (ie reacting to stress), and some animals can hear them, and some trees release pheromones to warn others about predation and downwind plants can pick this up and make themselves more bitter by ramping up tannin production. Plants are more interesting than they seem.

it does exist and it's called compost tea