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Tannosomes and the trickle-around effect: a new cell organelle is discovered

The views expressed are those of the author and are not necessarily those of Scientific American.


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Last week, when French researchers unveiled a newly discovered plant organelle related to wine and tea, I waited for frenetic coverage. And waited. Only a few obscure wine websites covered the news.

When I contacted the study co-author, Jean-Marc Brillouet of the French National Institute for Agricultural Research (INRA), he immediately put me in touch with another team member who could speak with me on short notice (Brillouet’s schedule was booked).

“It was the last frontier in plant biology,” co-author Charles Romieu, also of INRA, told me excitedly over the phone.

Ginkgophyta, one of the plants used in the study

After untold hours in the lab experimenting with different transmission electron microscopy (TEM) imaging methods, the team found a new organelle inside the plant cell: the tannosome. It’s responsible for churning out tannins, the naturally occurring molecules belonging to the polyphenols class of organic chemicals. If you’ve ever sipped wine, tasted tea, or paddled around in the tannic acid waters of the Florida Everglades, then you know what tannins are: bitter compounds. These important molecules are found in tree bark, vascular plant leaves and not-yet-ripe fruit. Tannins are nature’s way of saying, “Hey, back off” to would-be predators. They also offer UV protection.

“We were very happy because nobody knew exactly where the tannin occurred. It was really a mystery,” Romieu said.

Before the discovery of this separate organelle, at least one previous study hinted that tannins were perhaps in the tonoplast.

A short film of the tonoplast

But it turns out tannins have their own organelle factory. The tannosome helps cells synthesize highly toxic and insoluble compounds.

“People have been trying to figure this out since the 1960s,” said Ian Burbulis, a researcher in biochemistry and molecular genetics at the University of Virginia’s School of Medicine. His voice, too, was edged with enthusiasm.

 

“By understanding the molecular mechanism, we can engineer systems that direct payloads within different compartments of the cell, which could be used in anything from biofuels to changing the content of wine,” Burbulis explained.

Magnoliophyta - another type of sample used in the study. The Musca domestica is a bonus.

Co-author Romieu assured me that we are “just at the beginning of the story.” As more research is directed to the subject, then scientists can learn more about how tannins are polymerized, which could open up doors to a host of applications. “Regarding the length of the polymer, if we could affect the length, then we could play with that perhaps to make wine feel more smooth in the mouth,” Romieu told me, his French accent strong on the other end of the line.

At this point in the interview, I wished I spoke fluent French. My eagerness to understand this basic research finding ran up against my inability to speak either of Romieu’s languages: both French and the lexicon of plant biology. (The experience reminded me of a session that took place at the 8th World Congress of Science Journalists meeting I attended in June in Helsinki. The panelists debated the usefulness of battling English as the lingua franca of science. Unfortunately, the session was conducted in French.)

As always many scientific breakthroughs, the real work begins after the discoveries are made.

But later, perhaps in a few years, when you and I are enjoying a glass of wine or a cup of tea with modified tannins, we can thank the “trickle-around” effect of this single tannosome study for getting us to that point. In a surprisingly apt analogy, Meryl Streep’s character pays this sort of tribute in the film The Devil Wears Prada (2006) when she chastises a clueless intern (Anne Hathaway) for being unaware of her blue sweater’s fashion lineage.

 

Photo credit Kathleen Raven
Movie Credit Tonoplast – Mano, et. al.

References

Brillouet, J.M., et. al. (2013) Annals of Botany, 112 (5): 10.1093/aob/mct168

Lees, G.L., et. al. (1995) Canadian Journal of Botany, 73(12): 1897-1904, 10.1139/b95-202

Mano, S., et. al. (2011) The Plant Organelles Database 2 (PODB2): An updated resource containing movie data of plant organelle dynamics. Plant Cell Physiol. 52: 244-253. Link

Kathleen Raven About the Author: Kathleen Raven is a writer living in Atlanta, Georgia. She received her MS in Ecology with a focus on sustainable agriculture and MA in Health & Medical Journalism from the University of Georgia. Follow on Twitter @sci2mrow.

The views expressed are those of the author and are not necessarily those of Scientific American.






Comments 4 Comments

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  1. 1. Jerzy v. 3.0. 8:11 am 09/21/2013

    This is not Drosophila but likely Musca domestica. ;)

    Link to this
  2. 2. Kathleen Raven in reply to Kathleen Raven 9:41 am 09/21/2013

    Good call – and corrected in the caption, thanks!

    Link to this
  3. 3. Jen M 3:49 pm 09/30/2013

    Another comment about that same caption: “Magnoliophyta” refers to a division of plants, corresponding to about 250,000 species (or as many as 400,000 species, depending on who you ask). It is the scientific term used to refer to flowering plants. I don’t think the caption means to be referring to all flowering plants (since they weren’t all used in the study…that would take forever!).

    Link to this
  4. 4. Kathleen Raven in reply to Kathleen Raven 7:13 pm 09/30/2013

    Jen M, That is correct – the caption is not meant to convey that. Thanks for clarifying!

    Link to this

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