Trilobites: Watch Plants Light Up When They Get Attacked

Posted Thursday, 13 September 2018 ‐ The New York Times

Plants have no eyes, no ears, no mouth and no hands. They do not have a brain or a nervous system. Muscles? Forget them. They’re stuck where they started, soaking up the sun and sucking up nutrients from the soil. And yet, when something comes around to eat them, they sense it.
And they fight back.
How is this possible?
“You’ve got to think like a vegetable now,” says Simon Gilroy, a botanist who studies how plants sense and respond to their environments at the University of Wisconsin-Madison.
“Plants are not green animals,” Dr. Gilroy says. “Plants are different, but sometimes they’re remarkably similar to how animals operate.”
To reveal the secret workings of a plant’s threat communication system for a study published Thursday in Science, Masatsugu Toyota (now a professor at Saitama University in Japan) and other researchers in Dr. Gilroy’s lab sent in munching caterpillars like in the video above. They also slashed leaves with scissors.
They applied glutamate, an important neurotransmitter that helps neurons communicate in animals.
In these and about a dozen other videos, they used a glowing, green protein to trace calcium and accompanying chemical and electrical messages in the plant. And they watched beneath a microscope as warnings transited through the leafy green appendages, revealing that plants aren’t as passive as they seem.
[Like the Science Times page on Facebook.| Sign up for the Science Times newsletter.]
The messages start at the point of attack, where glutamate initiates a wave of calcium that propagates through the plant’s veins, or plumbing system. The deluge turns on stress hormones and genetic switches that open plant arsenals and prepare the plant to ward off attackers — with no thought or movement.
Like animals, plants are eukaryotes — multicellular organisms — that split from a common ancestor called Luca billions of years ago. To survive, we all sense threats, relay messages about them within our bodies or tissues and respond to these challenges. Our actions vary, adapted for the lifestyles we maintain in different environments, but much of our basic cellular machinery is the same. Biology kept it that way: If it ain’t broke, don’t fix it.
One mechanism our cells share is fluctuating levels of calcium ions, which carry an electrical charge. In humans, this charge assists in controlling when your neurons fire messages. Changes in calcium ions make your heart beat or your muscles contract so you can get up and leave when something threatens you.
Plants, obviously, can’t run away. But researchers knew that genes that make receptors kind of like those for glutamate initiate electrical signals that travel through plants after being wounded. They turn on genes elsewhere in the plant, allowing them to respond.
With the help of glutamate, calcium ions can flow, carrying their signal through channels that open like floodgates when glutamate fits into these special receptor spaces, like keys in locks. These channels aren’t quite the same as those in the mammalian nervous system, but they look very similar and probably worked similarly. They led Dr. Gilroy and his team to look into calcium ion flow.
To make the action visible, the researchers engineered Arabidopsis plants, botany’s lab rat, to make a protein originally from jellyfish that glows green under a microscope. This sensor, in this case, shines brighter when calcium levels increase.
They also made plants that lack the glutamate-like receptor. In these, the fluorescent signal was weak:
The real surprise was the speed. The plant reacted within a few seconds and transferred information from leaf to leaf in a couple of minutes — as long as they were connected through the vascular system. This is slower than your nervous system, but “for a plant biologist, that is booking it,” Dr. Gilroy said.
The plant also seemed to be able to sense the amount of damage, because when they crushed a leaf, the plant responded all over.:
Wherever the calcium touched, the plant produced jasmonic acid, a defense and stress hormone, which they believe turns on genes that somehow activate a plant’s chemical and physical defenses.
Methyl-jasmonate, a product of jasmonic acid, for instance, floats through the air like a jasmine-scented perfume. But for insects, it can be unappealing or disrupt digestion and deter diners from return visits. Physical defenses may harden a plant’s cell walls, too, making them tough to eat.
“The authors add many pieces to the puzzle of how a localized wound triggers widespread defenses in distal leaves,” said Ted Farmer, a botanist at University of Lausanne in Switzerland who described the electrical wound signal in plants.
But much is still a mystery.
“We’re trying to understand what the machinery is that makes the whole system work,” Dr. Gilroy said.
What isn’t so mysterious is that plants and animals have a lot of the same problems. And while humans can deal with threats, plants can too.
“They may even have to be better than us at sensing the environment because they don’t have the luxury of getting up and leaving,” Dr. Gilroy said.

Tag: #FlowersAndPlants #Chemistry #Science(journal) #Research #Gilroy,Simon #Evolution(biology) #Toyota,Masatsugu

Other articles published by The New York Times

Posted Tuesday, 11 December 2018 ‐ The New York Times

While we’re tracking the approach of the British Parliament’s vote on Brexit, we enlisted Ellen Barry, our London-based chief international correspondent, to take over the top of your daily briefing. Let us know what you think....

Posted Tuesday, 11 December 2018 ‐ The New York Times

WASHINGTON — On a July evening, Trump administration officials and allies, including the president’s personal lawyer, Rudolph W. Giuliani, gathered with investors atop the Hay-Adams hotel overlooking the White House for a cocktail reception featuring ...

Posted Tuesday, 11 December 2018 ‐ The New York Times

A high school football player in Indiana was charged with murder on Monday after the authorities said he fatally stabbed a 17-year-old classmate who was six months pregnant with their child. The football player, Aaron Trejo, 16, told the authorities that ...

Posted Tuesday, 11 December 2018 ‐ The New York Times

Institutional failures. Two leaders of American Olympic sports engaging in “efforts to protect and preserve their institutional interests” over the interests of vulnerable children. And an “ecosystem that facilitated” criminal acts. Those were...

Posted Tuesday, 11 December 2018 ‐ The New York Times

Donald Trump — or, as he’s known to federal prosecutors, Individual-1 — might well be a criminal. That’s no longer just my opinion, or that of Democratic activists. It is the finding of Trump’s own Justice Department. On Friday, federal...

Posted Tuesday, 11 December 2018 ‐ The New York Times

WASHINGTON — President Trump defended himself on Monday against prosecutors’ accusation that he directed illegal payments ahead of the 2016 election to two women to stay silent about alleged extramarital affairs with him, insisting that the payments...

Posted Tuesday, 11 December 2018 ‐ The New York Times

A four-foot bronze statue of a girl sporting a defiant look on her face appeared in Lower Manhattan on the eve of International Women’s Day in March 2017. The sculpture soon became known as the Fearless Girl, captivating New Yorkers and tourists...

Posted Tuesday, 11 December 2018 ‐ The New York Times

WASHINGTON — President Trump has often bragged about having his pick of only the best people to serve in his administration. Being publicly rejected by his first choice for chief of staff — and embarking on a very public search for someone else —...

Posted Tuesday, 11 December 2018 ‐ The New York Times

Want climate news in your inbox? Sign up here for Climate Fwd:, our email newsletter. WASHINGTON — The Trump administration is expected on Tuesday to unveil a plan that would weaken federal clean...

Posted Tuesday, 11 December 2018 ‐ The New York Times

“The most sacred duty of government is to protect people,” Mayor Bill de Blasio said, “especially defenseless children. There is nothing more barbaric than separating children from their parents. There is no excuse for this horror and certainly no...

Posted Tuesday, 11 December 2018 ‐ The New York Times

Knowing she would lose, Theresa May on Monday aborted a vote on her embattled Brexit deal. The humiliation of the moment was underscored by the derisive laughter in Parliament as the prime minister announced the delay, especially when she claimed there...

Posted Tuesday, 11 December 2018 ‐ The New York Times

He spent much of his time in his mother’s basement and in his bedroom with blacked-out windows, essentially turning into the “homebound recluse” a psychiatrist who had evaluated him feared he could become. He obsessed over violence, culling...

Posted Tuesday, 11 December 2018 ‐ The New York Times

In recent years, museums in the United States have surrendered antiquities to numerous countries after determining that the objects had been illicitly acquired. Those restitutions were necessary: no museum should retain a work that was stolen or...

Posted Monday, 10 December 2018 ‐ The New York Times

(Want to get this briefing by email? Here’s the sign-up.) Good evening. Here’s the latest. 1. Wanted: A new White House chief of staff. The hunt is on after President Trump announced over the...

Posted Monday, 10 December 2018 ‐ The New York Times

Donald Trump, it turns out, may have been the best thing that could have happened to American democracy. No, I haven’t lost my mind. Individual-1 is clearly a wannabe dictator who has contempt for the rule of law, not to mention being corrupt and...