Nav: Home

New insight into plants' self-defense

February 22, 2018

Chloroplasts are the ultimate green machines - the parts of plant cells that turn sunlight into food in a fairly famous process known as photosynthesis.

But they have another role of critical value to plant life. They are part of the signal corps that alerts a plant's immune system to the threat of danger - whether by enemy attack or environmental stressor.

Now University of Delaware researchers and collaborators at the University of California-Davis have uncovered new details of how chloroplasts move about in times of trouble. It's the fundamental kind of research information that helps scientists understand plant biology and could help farmers prevent crop loss.

Their findings were published by eLife Sciences.

Using bioimaging techniques at the Delaware Biotechnology Institute, a team led by Jeffrey Caplan, director of the Bioimaging Center, has shown that chloroplasts morph into dramatically different shapes when danger approaches, sending out hollow shoot-like parts called "stromules" as part of the plant's immune response. These stromules then connect to the cell's nucleus and appear to guide the chloroplasts to their assigned posts.

Researchers don't know yet if the stromules act as escorts or provide the impetus for this transit - or both. But the images show direct correlation.

"This could point to new methods for crop protection against various pathogens," Caplan said. "This is a basic response, not specific to any one pathogen."

For this study, researchers used cells from a relative of the tobacco plant - nicotiana benthamiana - which has many properties of value for study and imaging.

They used fluorescent proteins to mark structures in the cells - the stromules and the cytoskeleton - and those markers made it possible to monitor the structures with laser-scanning confocal microscopy. A confocal microscope, part of the expansive toolbox in DBI's Bioimaging Center, allows scientists to capture three-dimensional images of molecules.

In the same way, they can see the relationship between stromules, microtubules and the actin filaments that act as anchoring points as the stromules move along.

There is much to see, even in this tiniest of tiny contexts, where stromules vary in size from 1 micron to 10s of microns, up to 100 microns.

Guided - or perhaps propelled - by the stromules, the chloroplasts then cluster around the cell's nucleus as the battle against a pathogen develops. Researchers have found that increasing stromule formation also speeds a plant's immune response.

Future research can build on this new understanding of stromules to see if changing some of the dynamics can help a plant resist damage from disease and other stressors.

Eleven other researchers contributed to the article, and Caplan said beyond this team are many other UD researchers whose expertise often is helpful in such studies.

"UD has a wonderful work environment," Caplan said. "We work together to study many different aspects of disease resistance."
-end-
Caplan's UD collaborators on the project included: Amutha Sampath Kumar, Alexander Nedo, Ali Alqarni, Kyle Hoban and Shannon Modla, all of the Delaware Biotechnology Institute; Li Ren and Chandra Kambhamettu of the Department of Computer and Information Sciences; and John McDonald of the Department of Biological Sciences.

Also on the team was Eunsook Park and Savithramma Dinesh-Kumar of the Department of Plant Biology and The Genome Center at the University of California-Davis.

University of Delaware

Related Chloroplasts Articles:

Mutation reduces energy waste in plants
In a way, plants are energy wasters: in order to protect themselves from excessive electron transport, they continuously quench light energy and don't use it for photosynthesis and biomass production.
Plant physiology: Safeguarding chloroplasts from sunburn
Intense sunlight damages the chloroplasts that are essential for photosynthesis, and generates toxic products that can lead to cell death.
Unexpected discovery: Blue-green algae produce oil
Cyanobacteria -- colloquially also called blue-green algae - can produce oil from water and carbon dioxide with the help of light.
Biophysicists find 'extra' component in molecular motor
Researchers discovered an additional component in ATP synthase, a molecular machine that produces the energy-conserving compound.
How to build a chloroplast
When a plant begins growing its first leaves, it is in a race for survival to build its chloroplasts.
Changes in photochemical reflectance index can be used to monitor crop condition
Currently, agriculture remains one of the most labor-intensive and vital sectors of human activity.
Mystery behind striped barley solved
Albostrians barley is a model plant displaying variegation in form of green-white striping.
It's not easy being green
Despite how essential plants are for life on Earth, little is known about how parts of plant cells orchestrate growth and greening.
Plants are also stressed out
What will a three-degree-warmer world look like? When experiencing stress or damage from various sources, plants use chloroplast-to-nucleus communication to regulate gene expression and help them cope.
An easier way to engineer plants
MIT researchers have developed a genetic tool that could make it easier to engineer plants that can survive drought or resist fungal infections.
More Chloroplasts News and Chloroplasts Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Reinvention
Change is hard, but it's also an opportunity to discover and reimagine what you thought you knew. From our economy, to music, to even ourselves–this hour TED speakers explore the power of reinvention. Guests include OK Go lead singer Damian Kulash Jr., former college gymnastics coach Valorie Kondos Field, Stockton Mayor Michael Tubbs, and entrepreneur Nick Hanauer.
Now Playing: Science for the People

#562 Superbug to Bedside
By now we're all good and scared about antibiotic resistance, one of the many things coming to get us all. But there's good news, sort of. News antibiotics are coming out! How do they get tested? What does that kind of a trial look like and how does it happen? Host Bethany Brookeshire talks with Matt McCarthy, author of "Superbugs: The Race to Stop an Epidemic", about the ins and outs of testing a new antibiotic in the hospital.
Now Playing: Radiolab

Dispatch 6: Strange Times
Covid has disrupted the most basic routines of our days and nights. But in the middle of a conversation about how to fight the virus, we find a place impervious to the stalled plans and frenetic demands of the outside world. It's a very different kind of front line, where urgent work means moving slow, and time is marked out in tiny pre-planned steps. Then, on a walk through the woods, we consider how the tempo of our lives affects our minds and discover how the beats of biology shape our bodies. This episode was produced with help from Molly Webster and Tracie Hunte. Support Radiolab today at Radiolab.org/donate.