Monday, August 18, 2014

Plant talk

Entirely new form of plant communication discovered
Plants 'talk' to each other by sharing an extraordinary amount of genetic information, and it looks like parasitic plants could be using this to trick their hosts into submission.
Image: Virginia Tech College of Agriculture and Life Sciences
Jim Westwood, professor of plant pathology and physiology at Virginia Tech in the US, has found that plants ‘talk’ to each other on a molecular level, swapping DNA information in a way that parasitic plants might be taking advantage of.
Westwood made this discovery by looking at the interactions between a parasitic plant called adodder, and two types of host plants - a small flowering plant called an Arabidopsis, and a tomato plant. Also known as Cuscuta plants, dodders use a creeping appendage called ahaustorium to penetrate their host plants and feed on their nutrients. In previous studies, Westwood had discovered that during this interaction, RNA molecules - which play a crucial role in coding, decoding, regulating, and expressing information passed down from DNA - were being passed between the two species. 
More recently, Westwood looked into the possibility that a special type of RNA molecules -  mRNA, or messenger RNA - were also being transported between the parasitic and host plants. Messenger RNA molecules send messages within cells, instructing them on which actions to take and when. 
"It was thought that mRNA was very fragile and short-lived, so transferring it between species was unimaginable,” reports. "But Westwood found that during this parasitic relationship, thousands upon thousands of mRNA molecules were being exchanged between both plants, creating this open dialogue between the species that allows them to freely communicate.”
Here’s where it gets a bit sinister, because through this exchange of messenger RNA molecules, the parasitic dodder plant could be instructing the host plants on what to do, such as lowering their defences so the dodder can attack them with less resistance. Westwood plans to find this out in the next stage of his research.
"The discovery of this novel form of inter-organism communication shows that this is happening a lot more than any one has previously realised," said Westwood in a press release. "Now that we have found that they are sharing all this information, the next question is, 'What exactly are they telling each other?’.”
Other than giving us a much deeper insight into the behaviour of plants, this information could help scientists come up with better solutions to fight the parasitic weeds that threaten food crops in developing countries around the world.
"Parasitic plants such as witchweed and broomrape are serious problems for legumes and other crops that help feed some of the poorest regions in Africa and elsewhere," Julie Scholes, a professor at the University of Sheffield in UK who was not part of this project, said in the press release. "In addition to shedding new light on host-parasite communication, Westwood's findings have exciting implications for the design of novel control strategies based on disrupting the mRNA information that the parasite uses to reprogram the host.”
"The beauty of this discovery is that this mRNA could be the Achilles hill for parasites,"Westwood added. "This is all really exciting because there are so many potential implications surrounding this new information."
Westwood’s research was published today in the journal Science.

Sunday, August 17, 2014

New fungi in packet of dried mushrooms

New species of mushroom found in commercial packet
DNA sequencing revealed that a store-bought packet of what seemed to be dried porcini mushrooms contained three species with no scientific names.
Image: Rebecca Siegel/Flickr
Turns out your delicious pasta sauce may or may not contain porcini mushrooms!
Two mycologists from the Kew Royal Botanical Gardens in the UK, Bryn Dentinger and Laura Martinez-Suz, got unexpected results when they analysed the contents of a commercial packet of dried Chinese porcini mushrooms bought in a store in London. After doing DNA testing of the 15 pieces, they discovered that they belong to three previously unidentified species. 

Porcini mushrooms are consumed all over the world. It is estimated that annual worldwide production reaches up to 100,000 metric tonnes. But not all porcini are created equal—and this research reveals that they are much more diverse than we might think. 

China, where the packet originated, is one of the main exporters of this ingredient to Europe, but having an effective method of identification when collecting mushrooms in the wild can be difficult. 

Dentinger and Martinez-Suz’s diagnostic research aims to stress the importance of correctly identifying the food we eat, which, as they state in their paper, “is essential for regulating global food trade and identifying food frauds”.
Science Alert: 

Saving Lomatia tasmanica, an old plant

Botanists' bid to save King's Holly, 'world's oldest living plant', from extinction

King's Holly, otherwise known as Lomatia tasmanica, is believed to be at least 43,000 years old.
Only one cluster of the ancient plant remains in a secret southern Tasmanian location, surrounded by deadly root rot.
Tasmanian explorer, Denny King, discovered the plant in 1937.
It's believed there are fewer than 500 plants in the small secret location.
Greg Jordan, from the University of Tasmania, said King's Holly is probably the oldest living plant in the world.
"Definitely to date it's probably the best candidate for the oldest plant in the world," he said.
An intensive breeding program at Tasmania's Royal Botanical Gardens started in 2004.
The aim was to set up an insurance population of 50 plants in pots, but to date fewer than half have taken.
Mr Jordan said establishing an insurance population was a challenge.
Definitely to date it's probably the best candidate for the oldest plant in the world.
Greg Jordan
"The King's Holly doesn't do sex," he said.
"That's because it has three sets of chromosomes instead of two."
The plant bears pink flowers but produces neither fruit nor seeds.
It only reproduces vegetatively, meaning a new plant only grows when a branch falls and develops its own roots establishing a separate, but genetically identical, plant.
Natalie Tapson, from Tasmania's Royal Botanical Gardens, has been working with King's Holly for around two decades.
In that time several different techniques of growing the plant have been tried, but all have had their setbacks.
Ms Tapson said that while cuttings generally took root, they were difficult to transfer to larger pots.
"One of the issues is you get this blackening off, so whenever you cut a stem it blackens and it dies, so it's very very touchy," she said.
Ms Tapson now believes grafting King's Holly onto another plant could be the solution.
"By putting it on to a root stock, it's hoped that when you plant it out, or transfer it, you're not going to have that loss because the root stock is stronger," she said.
As well as root rot, scientists fear a fire could wipe the cluster out.
However, it's also feared a lack of fire could allow other plants to grow over the top of it.
First posted 9 Aug 2014, 10:11am
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