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:

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.
New biochemical pathway that may develop more resilient crop varieties
Researchers from the Department of Plant Sciences, University of Oxford, have discovered a new biochemical pathway in plants which they have named CHLORAD.
Growing the tallest is not always the best option
Plants compete with each other for sunlight, which is essential for plants to feed and grow.
A new way to transfer energy between cells
Researchers have described a new method for the transmission of electrons between proteins that refutes the evidence from experiments until now.
Scientists debunk potential link to crop cold tolerance
New research debunks a long-held theory that corn and other grass crops are susceptible to cold because they lack the space in their leaves needed to boost photosynthetic efficiency in low temperatures.
Heredity matters: Ancestral protease functions as protein import motor in chloroplasts
Japanese researchers identified a large novel protein complex in the inner chloroplast membrane that functions as a motor to import proteins into the chloroplast.
More Chloroplasts News and Chloroplasts Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.