BacterioFiles 415 - Global Glomus Growth Guesses

How mycorrhizal fungi work

By Nefronus, CC BY-SA 4.0

This episode: A global estimate of plants and their root fungi shows how agriculture may have greatly affected soil carbon storage over time!

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Show notes:
Microbe of the episode: Rhizobium virus RHEph4

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Takeaways
Even small organisms can have a big effect on the climate of the planet if there are enough of them. This includes trees, which are small relative to the planet, and also includes the fungi that attach to the roots of trees and other plants. These mycorrhizal fungi thread subtly through the soil, some occasionally popping up mushrooms, and transfer valuable nutrients they gather to the trees in exchange for carbon fixed from the air.

Knowing how big an effect a given kind of organism has requires knowing how much of it is around. This study collates data from various surveys of global plant populations and the fungi that interact with their roots, to estimate a global picture of the fungi below our feet. It estimates that a kind of fungus that stores more carbon in the soil may have been replaced in many areas with fungi that store less, or no fungi at all, due to the transformation of land from wild areas to farmland.

Journal Paper:
Soudzilovskaia NA, van Bodegom PM, Terrer C, Zelfde M van’t, McCallum I, Luke McCormack M, Fisher JB, Brundrett MC, de Sá NC, Tedersoo L. 2019. Global mycorrhizal plant distribution linked to terrestrial carbon stocks. Nat Commun 10:1–10.

Other interesting stories:

• Phages bind to fish mucosal surfaces and protect from infection
• Examining how archaea affect meteorites

Post questions or comments here or email to bacteriofiles@gmail.com. Thanks for listening!

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BacterioFiles 414 - Producing Proton Power Perpetually

Microalgae Chlamydomonas reinhardtii

This episode: Microalgae can produce hydrogen, but other metabolic pathways take priority, except when special engineered hydrogenase enzymes can overcome this limitation!

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Show notes:
Microbe of the episode: Alphapapillomavirus 11

Takeaways
There are many options being explored as ways to replace fossil fuels. Electricity and batteries are good, but they have their limitations, especially for long-distance high-energy travel such as airplanes. Hydrogen is one good option: high energy density, clean-burning, simple to produce. Microbes can produce hydrogen through various metabolic pathways, including fermentation, nitrogen fixation byproduct, and photosynthesis. However, competing metabolic pathways make microbial hydrogen production less efficient.

In this study, scientists engineer a hydrogenase enzyme for hydrogen production in microalgae that can compete better with carbon fixation as a destination for the electrons and protons that hydrogen production requires. This engineered enzyme allowed the algae to produce hydrogen continuously, even during photosynthesis.

Journal Paper:
Ben-Zvi O, Dafni E, Feldman Y, Yacoby I. 2019. Re-routing photosynthetic energy for continuous hydrogen production in vivo. Biotechnol Biofuels 12:266.

Other interesting stories:

• Plants use arsenic-dumping genes from bacteria to get essential nutrients
• Another study engineering better viruses for phage therapy

Post questions or comments here or email to bacteriofiles@gmail.com. Thanks for listening!

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BacterioFiles 413 - Finding Fire Fungi Footholds

Pyrophilous fungus
Pholiota highlandensis

This episode: Some fungi only form fruiting bodies after forest fires; where do they hide the rest of the time? At least for some of them, the answer is: inside mosses!

Thanks to Daniel Raudabaugh for his contribution!

Download Episode (6.2 MB, 9.0 minutes)

Show notes:
Microbe of the episode: Nocardia brevicatena

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Takeaways
Forest fires can do a lot of damage, but life grows back quickly. Certain kinds of plant seed actually only germinate after a fire, and a similar thing is true of certain kinds of fungi: they only form fruiting bodies (like mushrooms, for spreading spores) after a fire. For plants, the advantage may come from increased access to light with some or all of the canopy burned away, and fungi may benefit from less competition on the ground. But in between burn events, these fire-loving (pyrophilous) fungi seem to disappear. Where do they go?

The study here sought an answer, suspecting an association with some mosses that reappeared soon after a forest fire in North Carolina in 2016. They looked for fungi lurking as endophytes inside moss and other samples, both by growing them on agar and by DNA sequencing, and they found a number of different known pyrophilous fungi. Some of these were in soil, or samples from outside the burned area, but the majority were inside mosses growing in the recently burned zone.

Journal Paper:
Raudabaugh DB, Matheny PB, Hughes KW, Iturriaga T, Sargent M, Miller AN. 2020. Where are they hiding? Testing the body snatchers hypothesis in pyrophilous fungi. Fungal Ecol 43:100870.

Other interesting stories:

• Probiotic yeast species could inhibit pathogenic yeasts (paper)
• Plant passes on nitrogen fixing symbionts to offspring

Post questions or comments here or email to bacteriofiles@gmail.com. Thanks for listening!

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BacterioFiles 412 - Carbon Concentration Complicates Crop Cooperation

Wheat plants
By Bluemoose, CC BY-SA 3.0

This episode: Looking at the effects of almost doubling CO₂ concentrations on the interaction between wheat varieties and beneficial fungi!

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Show notes:
Microbe of the episode: Lato River virus

News item

Takeaways
As the world's population grows, feeding everyone will grow more challenging. Advances in technology in the past have made today's population possible, but future advances may be needed, especially in the face of an increasing concentration of carbon dioxide in the atmosphere.

Soil microbes that partner with crop plants for the benefit of each may be part of the solution. One option to explore is a group called mycorrhizal fungi, which associate with plant roots to extend their nutrient-gathering ability, in exchange for carbon compounds produced by photosynthesis. This study examined the influence of increased carbon dioxide in the atmosphere on the interaction of several varieties of wheat with these fungi.

Journal Paper:
Thirkell TJ, Pastok D, Field KJ. Carbon for nutrient exchange between arbuscular mycorrhizal fungi and wheat varies according to cultivar and changes in atmospheric carbon dioxide concentration. Glob Change Biol.

Other interesting stories:

• Microbes could make paper whitening more environmentally friendly (paper)
• Compound from rotifers could prevent transmission of eukaryotic parasite

Post questions or comments here or email to bacteriofiles@gmail.com. Thanks for listening!

Subscribe: Apple Podcasts, Google Podcasts, Android, or RSS. Support the show at Patreon, or check out the show at Twitter or Facebook.