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Chloroplast tubes play a key role in plants' immune defense

Date:
June 25, 2015
Source:
University of California - Davis
Summary:
When plant cells are infected with pathogens, networks of tiny tubes called stromules grow from the chloroplasts to the cell's nucleus and trigger programmed cell death and innate immune responses.
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Infection causes tubes called stromules (blue) to grow from chloroplasts (purple) to the nucleus of a plant cell (yellow) carrying signals that boost immune defenses.
Credit: Image courtesy of University of California - Davis

Chloroplasts, better known for taking care of photosynthesis in plant cells, play an unexpected role in responding to infections in plants, researchers at UC Davis and the University of Delaware have found.

When plant cells are infected with pathogens, networks of tiny tubes called stromules extend from the chloroplasts and make contact with the cell's nucleus, the team discovered. The tubes likely deliver signals from the chloroplast to the nucleus that induce programmed cell death of infected cells and prepare other cells to resist infection. The work is published online June 25 in the journal Developmental Cell.

"This opens a new area of understanding how the chloroplast communicates with the nucleus, and likely with other organelles within the cell," said Savithramma Dinesh-Kumar, professor of plant biology at UC Davis and senior author on the paper.

Chloroplasts in neighboring uninfected cells also produce stromules, apparently signaling the nucleus to switch on genes that make cells more resistant to infection. The overall effect is to wall off and contain an infection, Dinesh-Kumar said.

Stromules were first described more than 50 years ago, but until now their role in a specific biological process has remained a mystery.

Mammalian cells lack chloroplasts but do have mitochondria, which play a role in cellular suicide. Exactly what chloroplasts, do other than photosynthesis, has been largely ignored, Dinesh-Kumar said. But it's clear that they are "powerhouses" producing molecules for the rest of the cell.


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Materials provided by University of California - Davis. Note: Content may be edited for style and length.


Journal Reference:

  1. Jeffrey L. Caplan, Amutha Sampath Kumar, Eunsook Park, Meenu S. Padmanabhan, Kyle Hoban, Shannon Modla, Kirk Czymmek, Savithramma P. Dinesh-Kumar. Chloroplast Stromules Function during Innate Immunity. Developmental Cell, 2015; DOI: 10.1016/j.devcel.2015.05.011

Cite This Page:

University of California - Davis. "Chloroplast tubes play a key role in plants' immune defense." ScienceDaily. ScienceDaily, 25 June 2015. <www.sciencedaily.com/releases/2015/06/150625145244.htm>.
University of California - Davis. (2015, June 25). Chloroplast tubes play a key role in plants' immune defense. ScienceDaily. Retrieved May 24, 2017 from www.sciencedaily.com/releases/2015/06/150625145244.htm
University of California - Davis. "Chloroplast tubes play a key role in plants' immune defense." ScienceDaily. www.sciencedaily.com/releases/2015/06/150625145244.htm (accessed May 24, 2017).

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