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Archive for the ‘Host plant resistance’ Category

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  • Fungus-resistant gene found in rice

   

Scientists in Japan have found a way to create high-yielding rice with long-lasting resistance to the devastating rice blast fungus.

Sufficient rice to feed 60 million people is destroyed by the blast fungus, Magnaporthe grisea — also known as Magnaporthe oryzae — every year.

Some rice is naturally resistant but is often also of lower yield. Now a team led by Shuichi Fukuoka from the National Institute of Agrobiological Sciences in Japan has engineered good quality rice that is both resistant to blast disease and high-yielding.

Their research was published in Science last week (21 August).

By comparing japonica rice that is resistant to blast disease with rice that succumbs to infection, Fukuoka found that a change in a key gene called Pi21 can mean the difference between devastating infection and mild disease.

Fukuoka says even plants with the resistant form of the gene become infected, but “The damage they suffer is not so serious, making it possible to reduce the amount of fungicide used by 50 per cent.”

He says his team’s findings will be particularly useful in mountainous areas where blast disease is a serious threat.

There have been many previous attempts to engineer resistant rice strains by making specific adjustments to plant immunity to allow the plants to recognise and resist the fungus.

But according to Nick Talbot, professor of molecular genetics at Exeter University in the UK, many of these modifications have a field life of just 2–3 years, as the fungus is quick to find ways to circumvent them and avoid being recognised.

Having the resistant form of Pi21, however, means a plant increases its defences against infection in general, making it much harder for the blast fungus to find a way to take hold, says Talbot.

He says the Japanese researchers have made a big discovery with universal applicability. When this is combined with other methods of engineering rice, scientists may be in a position to “exclude blast infections in a durable manner”.

Fukuoka has also managed to isolate the resistant form of Pi21, meaning it can be separated from other genes associated with poor yield. Previously this has been difficult because when scientists have tried to transfer the resistant Pi21 gene into new strains of rice, the genes affecting quality have also hitched a ride.

Fukuoka says the fact that his research has shown the exact location of the Pi21 gene means scientists can ensure it is not replaced by a more vulnerable form when breeding new rice strains.

Link to full article in Science

 

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The “big rust’s” impact on coffee disease management Coffee rust has made significant headlines in recent years for its devastating effect on coffee crops. According to the United States Agency for International Development (USAID), losses in Latin America and the Caribbean alone have totaled well over $1 billion, causing hardship to coffee plantations, their labourers, coffee retailers, and the consumers who pay more for their morning coffee.

But this fungal disease, also known as “the big rust,” has a much longer and more encompassing history that goes all the way back to its discovery in 1869. This history is reviewed in detail through a new Phytopathology article entitled, “The Big Rust and the Red Queen: Long-Term Perspectives on Coffee Rust Research,” written by Stuart McCook, historian at the University of Guelph in Ontario, Canada, and John Vandermeer, professor of ecology and evolutionary biology at the University of Michigan, USA.

In this essay, the authors discuss the big rust in a broader historical context, chronicling coffee rust epidemics, the social and ecological conditions that produced them, and the evolving scientific responses to this threat. The article highlights the many innovations used to combat coffee disease outbreaks, such as the efforts to develop disease-resistant plants, chemical and agroecological control, and even a network of international coffee research institutes. It also incorporates the broader social and economic histories of coffee production into particular stories of rust epidemics and rust research. The article also points out examples of the current research and disease mitigation challenges in developing nations versus affluent parts of the world.

By taking this broad perspective, the authors suggest we are entering a new phase in the global history of the coffee rust.

“Up until the mid-1980s, the story of the coffee rust was largely the story of invasions, as the disease spread into regions where it was not previously present,” McCook said. “By the mid-1980s, however, the disease had reached almost every coffee-producing region in the world.”

“For a brief while, in the 1980s and 1990s, it looked as if coffee farmers-with the help of scientists-had adapted to the disease, making it ‘just another disease’ on the farm. But we suggest that this fragile equilibrium has begun to break down, both because of broader ecological changes that we are only beginning to understand, and also because of increasing volatility in the global coffee economy,” he said.

Read this paper in the September 2015 issue of Phytopathology.

(Phytopathology News, November 2015)

http://www.isppweb.org/nldec15.asp#2

 

 

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IMustapha KSU248hessfly_adultHessian Fly

Mustapha El-Bouhssini (MS ’86, PhD ’92) Aleppo, Syria, is a global authority on plant resistance to insects in grains and has worked to develop crop varieties resistant to several important arthropod pests.

He recently received the Distinguished Scientist Award from the International Branch of the Entomological Society of America for significant contributions to entomological research.

El-Bouhssini serves as an adjunct faculty member in the Department of Entomology. This position has helped initiate collaborative projects between K-State and ICARDA on Hessian fly genetics and resistance in barley to the Russian wheat aphid.

From the KSU AgReport Spring 2015

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Mike smith  KSU251

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GM rice

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New GM Rice Shows Improved Disease Immunity
09 April 2015

 

 

US – Rice disease immunity can be improved by transferred genes from other species, according to new research from the University of California-Davis.

Rice is well equipped with an effective immune system that enables it to detect and fend off disease-causing microbes.

However, the new study showed that immunity can be further boosted when the rice plant receives a receptor protein from a completely different plant species via genetic engineering.

Lead author Benjamin Schwessinger, a postdoctoral scholar in the UC Davis Department of Plant Pathology, said: “Our results demonstrate that disease resistance in rice, and possibly related crop species, could very likely be enhanced by transferring genes responsible for specific immune receptors from dicotyledonous plants into rice, which is a monocotyledonous crop.”

Immune receptors are specialised proteins that can recognise patterns associated with disease-causing microbes, including bacteria and fungi, at the beginning of an infection.

These receptors are found on the surface of plant cells, where they play a key role in the plant’s early warning system.

Some of the receptors, however, occur only in certain groups of plant species.

Mr Schwessinger and colleagues successfully transferred the gene for an immune receptor from the model plant Arabidopsis thaliana, a member of the mustard family, into rice.

The rice plants that produced the Arabidopsis immune receptor proteins were more resistant to Xanthomonas oryzae pv. oryzae, an important bacterial disease of rice.

This demonstrated that receptors introduced to rice were able to make use of the rice plants’ native immune signalling mechanisms and cause the rice plants to launch a stronger defensive immune response against the invading bacteria.

– See more at: http://www.thecropsite.com/news/17505/new-gm-rice-shows-improved-disease-immunity/#sthash.p1mpfiJL.dpuf

 

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PHYS ORG

Mar 30, 2015

13-scientistsfi

Scientists find a gene to help protect potatoes from a blight that unleashed a devastating famine in Ireland in the 19th century.

 

Scientists on Monday said they have found a gene to help protect potatoes from a blight that unleashed a devastating famine in Ireland in the 19th century.

The genes were located after an exhaustive 10-year trawl through the genomes of wild potato varieties, according to their work, published in the journal Nature Plants.
Potato blight is caused by a pathogen known by its Latin name as Phytophthora infestans.
It has traditionally been described as a fungus, but closer inspection puts it in the same family as oomycetes, or water moulds.
P. infestans has a place in the history books as a mass murderer, inflicting a famine in Ireland in the 1840s that killed around a million people through starvation and disease and prompted around two million more to emigrate.
It remains a threat today. The blight inflicts billions of dollars annually in harvest damage to potatoes, the most important food crop after grains, and the disease is kept in check only through repeated chemical spraying.
The new study entailed a search for genes that trigger an immune response in potato plants, killing cells around the site of infection and thus limiting the spread of the disease.
The genetic treasure, called the elicitin response (ELR) gene, was found in a South American wild potato called Solanum microdontum, a native of Bolivia and Argentina.
ELR works in association with a key gene in the immune system, BAK1/SERK1, according to the researchers, led by Vivianne Vleeshouwers of Wageningen University in The Netherlands.
The researchers inserted the gene into the cultivated potato called Desiree, and found it was more resistant to several strains of blight.
ELR “could potentially enhance disease resistance to a number of oomycete plant pathogens, many of which are serious threats to a variety of crops and to world food security,” the paper said.
Explore further: Rediscovering Ireland’s rich history of wild plants​
More information: Nature Plants, DOI: 10.1038/nplants.2015.34
Journal reference: Nature Plants

© 2015 AFP
Read more at: http://phys.org/news/2015-03-spuds-scientists-shield-potato-blight.html#jCp

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112146-3d926a8c-cecf-11e4-bd1f-b87f4e1d2505Gene therapy: Professor James Dale with genetically modified Cavendish bananas, which could hold the key to saving the Far North’s banana industry from Panama disease. Picture: QUT/Erika Fish

KIMBERLEY VLASIC

THE CAIRNS POST

MARCH 23, 2015 11:51AM

THE development of the world’s only “super bananas”, which could save the Far North’s $570 million industry from Panama disease, has been stalled by the Northern Territory Government.

Queensland scientists trialling genetically modified (GM) Cavendish bananas near Darwin have been served with an eviction notice as the Top End focuses on eradicating a different, less threatening fungus called “banana freckle”.

The decision delays their globally significant research on Panama disease Tropical Race 4 and could mean Far Northern banana growers will be waiting longer for a resistant variety to become commercially available.

Heidi Quagliata, the daughter of the Dingo Pocket banana farmer affected by TR4, wants authorities to prioritise the disease that has crippled her family’s business.

The Robsons’ 160ha property was quarantined this month after testing positive for TR4 in the first Australian case outside the NT.

Samples taken from other banana farms were yesterday cleared of the disease, while further testing has confirmed the strain of TR4 at the infected property to be the most common one.

“I don’t know much about banana freckle but they should both be on a high priority list,” Mrs Quagliata said.

“TR4 seems to be the one that stays around longer, so resources should be more focused on that.”

Banana freckle affects the leaves and fruit of banana plants, causing blemishes on the fruit reducing their value.

banana 112228-b30609f6-cef0-11e4-bd1f-b87f4e1d2505 (1)Eradication: Banana Freckle Response inspector and team leader Maurice Thompson (left) and team member Ronald Bond carry away one of the last banana trees in the Northern Territory Botanical Garden area. Picture: Ivan Rachman
A national biosecurity response is under way to eradicate the disease from the NT and Australia after a new strain that infects a wide range of varieties, including Cavendish, was found in 2013.

This involves destroying all banana plants, including the “super bananas” being trialled, from six heavily infected sites by next month.

“As far as I know, we’re the only group in the world that are developing GM bananas that could have resistance to TR4,” said Professor James Dale, director of the Queensland University of Technology’s Centre for Tropical Crops and Biocommodities.

“We completely understand the biosecurity plan to eradicate all bananas, if they can eradicate freckle that would be terrific.

“Banana freckle won’t wipe out the industry, whereas TR4 already has in the NT, but it really is a good idea to eradicate it, it’s just unfortunate timing with our field trial.”

Prof Dale and his team have transferred genes from a wild banana found in Indonesia and Malaysia to create the GM banana.

He said it could be released commercially in 6-8 years if trials were successful.

“We’re very pleased with the results so far and we’re going to do a final assessment at the end of April,” he said.

“We’ll probably have at least 12 months out of the ground and then hopefully, if freckle is eradicated, we’ll be able to go back and recommence field trials in the NT.”

Prof Dale ruled out moving trials to Tully Valley.

Australian Banana Growers’ Council chief executive officer Jim Pekin said the NT Government was acting on the “unanimous advice of all jurisdictions” in destroying the GM banana plants.

“The ABGC supports the Banana Freckle response plan and is aware that this will unfortunately delay research trials in the NT eradication zones,” he said.

Originally published as NT dashes ‘super banana’ trials

 

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