Natures wonders: termites and fungi in symbiosis (Introduction)

by David Turell @, Tuesday, April 18, 2017, 20:01 (1257 days ago) @ David Turell

The two organisms have evolved to need each other in digesting wood:

"According to a study published in the journal Proceedings of the National Academy of Sciences, when poplar wood undergoes a short, 3.5-hour transit through the gut of the termite, the emerging feces is almost devoid of lignin, the hard and abundant polymer that gives plant cells walls their sturdiness. As lignin is notorious for being difficult to degrade, and remains a costly obstacle for wood processing industries such as biofuels and paper, the termite is the keeper of a highly sought after secret: a natural system for fully breaking down biomass.

"'The speed and efficiency with which the termite is breaking down the lignin polymer is totally unexpected," says John Ralph, a UW-Madison professor of biochemistry, researcher at the Great Lakes Bioenergy Research Center (GLBRC) and lignin expert. "The tantalizing implication is that this gut system holds keys to breaking down lignin using processes that are completely unknown."

"Hongjie Li, co-first author of the study, began studying the termite as graduate student at Zhejiang University in Hangzhou, China. Now a postdoctoral researcher in the lab of UW-Madison bacteriology professor and GLBRC researcher Cameron Currie, Li was the first to keep this genus of termite alive in a lab setting, and the first to observe close-up the symbiotic system that unites the termites with the white rot fungus Termitomyces.

"The entire process, as is often the case with social insects, is complex. Young termites, or young workers, collect and eat the wood. The termites' fungal-laden feces then become an integral part of a fungal comb, a sponge-like structure the termites create within a protected chamber. On the comb, the white rot fungi further degrade the wood until its simple sugars are ready, some 45 days later, to be consumed by old worker termites.


"'This system is unique because the fungus and the termite can't live without each other," says Yelle. "They're symbiotic, and they work together very efficiently to do things white rot fungi can't do in nature. Together they do everything more rapidly."

"The system may be symbiotic, but the processes involved in the gut transit -- or the mechanisms by which the termite gut succeeds in cleaving even the hardest-to-cleave portions of the lignin -- are still unknown. Future research will focus on determining which enzymes or bacterial systems might be at work in the gut. If that super enzyme or process can be replicated outside of the termite, it could result in a dramatic improvement in the way we process wood and make biofuels, improving economics and cutting energy use.

"'This is a great example of the value of basic science research," says Currie. "Studying how termites process plant biomass in nature not only helps us understand our natural world, but it could contribute to our own efforts to break down biomass.'"

Comment: Since they are so interdependent, we can wonder how they got together. Did the termites pick a specific fungus or simply picked one and worked with it. But the feeding of sugar to older termites requires the system be in operation from the beginning. It appedars to be irreducibly complex, and therefore requires saltation.

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