Featured Research

from universities, journals, and other organizations

Calcium waves help the roots tell the shoots

Date:
April 3, 2014
Source:
University of Wisconsin-Madison
Summary:
For Simon Gilroy, sometimes seeing is believing. In this case, it was seeing the wave of calcium sweep root-to-shoot in the plants the professor of botany is studying that made him a believer. He demonstrated what long had been suspected but long had eluded scientists: that calcium is involved in rapid plant cell communication.

Simon Gilroy and colleagues showed what long had been suspected but long had eluded scientists: that calcium is involved in rapid plant cell communication, as discovered in Arabidopsis thaliana (above). No one had ever been able to see it before.
Credit: Oregon State University

For Simon Gilroy, sometimes seeing is believing. In this case, it was seeing the wave of calcium sweep root-to-shoot in the plants the University of Wisconsin-Madison professor of botany is studying that made him a believer.

Gilroy and colleagues, in a March 24, 2014 paper in the Proceedings of the National Academy of Sciences, showed what long had been suspected but long had eluded scientists: that calcium is involved in rapid plant cell communication.

It's a finding that has implications for those interested in how plants adapt to and thrive in changing environments. For instance, it may help agricultural scientists understand how to make more salt- or drought-tolerant plants.

"How do you think plants live?" Gilroy asks. "If I poke you, I see an instant response. You move away. Plants live in a slightly different world. They are rooted to the ground, literally, and they respond to the world either by growing or creating chemicals."

Calcium is involved in transmitting information in the cells of humans and other animals, contracting muscles, sending nerve signals and more.

In plants, scientists believed it had to also play a role in processing information and sending rapid signals so that plants can respond quickly to their environments.

Imagine you are a plant being eaten by a caterpillar: "It's like a lion chewing your leg," says Gilroy. "If an insect is chewing your leaf, you're gone unless you determine something effective immediately."

But no one had ever been able to see it before. Even Gilroy's team found it by accident.

The team was using a specific calcium sensor they thought wasn't going to work. They speculated it could serve as a control in their studies.

The sensor's brightness changes in the presence of calcium, displayed on screen as a change from green to red through a process known as fluorescence resonance energy transfer, or FRET. Typically, this particular sensor is so sensitive to calcium it is nearly always red.

But when researchers applied stress to the tip of a plant's roots -- a high concentration of sodium chloride salt -- it triggered a wave of red that traveled rapidly from the root to the top of the plant.

"We were kind of like, 'Why is it even working?' says Gilroy. "It was probably telling us we were looking in the wrong realm. It's like we could only hear the people shouting and we couldn't hear the talking."

The calcium wave, a flush of red on an otherwise green palette, traveled on a scale of milliseconds, traversing about eight plant cells per second -- too quick to be explained by simple diffusion of salt.

"It fit with a lot of our models," Gilroy says. "But the idea that it's a wave is one step beyond what our models would predict."

Within 10 minutes of applying a small amount of salt to the plants' roots, typical stress response genes were turned on in the plant.

Also turned on was the machinery to make more of a protein channel called two pore channel 1 (TPC1). Within one-to-two minutes, there was 10 times more of the building blocks needed to make the channel, which is thought to be involved in calcium signaling.

Gilroy and his team then looked at plants with a defect in TPC1. They had a much slower calcium wave -- about 25 times slower -- than plants with normal TPC1. When they studied plants expressing more of the TPC1 protein, the calcium wave moved 1.7 times faster.

Plants with more channels also grew larger and contained more chlorophyll than plants with normal or mutated TPC1 when grown in salt water.

The protein channel is present in all land plants, says Gilroy, and it's found throughout the plant. This is one of the many reasons it surprised the team to learn the calcium wave moves only through specific cells in the plant, like electrical signals moving through nerve cells in humans and other animals.

"We weren't expecting that," Gilroy says. "It means specific cell types have specific functions … there must be something special about those cells. We're really at the beginning."

The lab is now looking at the molecular machinery that makes up TPC1, to figure out how the parts of the channel work.

And now that the scientists know that calcium talks, the volume is turned up. The work is just getting started.

"We can hear the screaming," says Gilroy. "Now we're trying to see what the vocal chords are doing."


Story Source:

The above story is based on materials provided by University of Wisconsin-Madison. The original article was written by Kelly April Tyrrell. Note: Materials may be edited for content and length.


Journal Reference:

  1. W.-G. Choi, M. Toyota, S.-H. Kim, R. Hilleary, S. Gilroy. Salt stress-induced Ca2 waves are associated with rapid, long-distance root-to-shoot signaling in plants. Proceedings of the National Academy of Sciences, 2014; DOI: 10.1073/pnas.1319955111

Cite This Page:

University of Wisconsin-Madison. "Calcium waves help the roots tell the shoots." ScienceDaily. ScienceDaily, 3 April 2014. <www.sciencedaily.com/releases/2014/04/140403212400.htm>.
University of Wisconsin-Madison. (2014, April 3). Calcium waves help the roots tell the shoots. ScienceDaily. Retrieved September 17, 2014 from www.sciencedaily.com/releases/2014/04/140403212400.htm
University of Wisconsin-Madison. "Calcium waves help the roots tell the shoots." ScienceDaily. www.sciencedaily.com/releases/2014/04/140403212400.htm (accessed September 17, 2014).

Share This



More Plants & Animals News

Wednesday, September 17, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Some Tobacco Farmers Thrive Amid Challenges

Some Tobacco Farmers Thrive Amid Challenges

AP (Sep. 16, 2014) The South's tobacco country is surviving, and even thriving in some cases, as demand overseas keeps growers in the fields of one of America's oldest cash crops. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

Scientists Given Rare Glimpse of 350-Kilo Colossal Squid

AFP (Sep. 16, 2014) Scientists say a female colossal squid weighing an estimated 350 kilograms (770 lbs) and thought to be only the second intact specimen ever found was carrying eggs when discovered in the Antarctic. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com
Raw: Scientists Examine Colossal Squid

Raw: Scientists Examine Colossal Squid

AP (Sep. 16, 2014) Squid experts in New Zealand thawed and examined an unusual catch on Tuesday: a colossal squid. It was captured in Antarctica's remote Ross Sea in December last year and has been frozen for eight months. (Sept. 16) Video provided by AP
Powered by NewsLook.com
Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

Ivorians Abandon Monkey Pets in Fear Over Ebola Virus

AFP (Sep. 16, 2014) Since the arrival of Ebola in Ivory Coast, Ivorians have been abandoning their pets, particularly monkeys, in the fear that they may transmit the virus. Duration: 00:47 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins