Importance of Microbiomes: around root tips (Introduction)

by David Turell , Monday, July 08, 2024, 17:28 (136 days ago) @ David Turell

A review of functions:

https://www.the-scientist.com/getting-to-the-root-of-the-plant-microbiota-71994?utm_cam...

"...roots are responsible for nutrient acquisition, they interact with robust microbial communities, and both are split into segments with different functions.1-3 As roots wind their way through the soil, they create an underground network responsible for anchoring a plant’s above-ground portion, absorbing water, and communicating with the environment. Different root segments, including the differentiation zone, elongation zone, and root tip, are heterogeneous in their architecture, gene expression, immune state, and metabolic profiles, all of which may influence the root microbiota.

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"...Loo and her colleagues discovered that the spatial distribution of a root’s excreted metabolites similarly pattern the microbial community along its length.6 These findings shed light on host-microbe interactions and could support plant health initiatives by highlighting how to modulate the microbiota, which has implications for plant immune responses, stress tolerance, and more.

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"Most plants have a number of sugar transporters that distribute carbohydrates.9 To determine if they had a role in metabolite spatial organization, Loo analyzed publicly-available plant gene expression data sets and found that certain SWEET (sugars will eventually be transported) sugar transporter genes had specific spatial distribution patterns along the A. thaliana root.

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"Back in her laboratory, Loo found that in plants grown in a sterile medium, SWEET transporters ended up in different places along the root compared to those in plants grown in bacteria-containing ArtSoil. Loo’s team also sequenced the bacterial microbiota within the plants’ internal tissues and found that various A. thaliana harboring SWEET mutations had different community organization compared to wild-type plants. Metabolite abundance was also affected in the mutants.

“'This was not clearly shown until now … this micro-niche concept, where we have different exudates … and, of course, different microorganisms that are associated with these different younger and older parts of the roots,” said Alga Zuccaro, a plant-microbe interactions researcher at the University of Cologne, who was not involved in this study. “The biggest strength is that the paper really shows that there is a spatially separated sugar transport event … and this correlates with the presence and absence of different microbiota in these different areas of the roots.”

"'From now on, we will have to really think about the roots as an organ that has different areas that are colonized in a different way." [Zuccaro]

"The exact mechanism driving the spatial relationship of the microbiota and SWEET transporters is not yet clear. For future experiments, Loo hopes to fine-tune the root protocol—a need that Zuccaro also highlighted. “The next step would be to go for even smaller fractions … and look at single cells,” said Zuccaro. This would allow the researchers to determine the transporters’ spatial distributions not only longitudinally but from the external epidermis through the internal endodermis."

Comment: each segment of a root has its own special microbiome. It is a direct comparison to our gut microbiome. Bacteria fill an important role in supporting life with very few bad actors.