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Date: July 18, 2017
Source: eLife
Summary:
Researchers have discovered how a severe rice virus reproduces inside the small brown planthopper, a major carrier of the virus.
FULL STORY

A small brown planthopper — a member of a species known for being a major carrier of rice stripe virus — feeding on a rice plant.
Credit: Junjie Zhu

Researchers from the Chinese Academy of Sciences’ Institute of Zoology have discovered how a severe rice virus reproduces inside the small brown planthopper, a major carrier of the virus.

“Most plant viruses depend on insects to carry them between plants, and many can reproduce inside the cells of these carrier insects, or ‘vectors’, without actually harming them,” says Feng Cui, Professor of Zoology. “RSV, one of the most notorious plant viruses, is carried by the small brown planthopper and, once inside the cells, manages to achieve a balance with the insect’s immune system.”

Viral infections in animal hosts activate a pathway by which a type of enzyme, called c-Jun N-terminal kinase (JNK), is signalled to respond. But how exactly viruses regulate this pathway in vectors remains an open question, and Cui says the answer would provide important clues for intervening in the spread of plant viruses.

To address this question, Cui and her team explored the effect of RSV on the JNK signalling pathway in the small brown planthopper. Studying interactions between proteins, and using an analytical method to determine the compounds that are important for the JNK signalling pathway, they found that the virus activates the pathway in various ways — especially through the interaction of a planthopper protein called G protein pathway suppressor 2 (GPS2), and a viral protein called capsid protein.

“The interaction between these two proteins promotes RSV reproduction inside the planthopper, ultimately leading to disease outbreak when the insect carries the virus among rice crops,” says first author and postdoctoral researcher Wei Wang.

“We discovered that RSV infection increased the level of another protein called Tumor Necrosis Factor-α (TNF-α) and decreased the level of GPS2 in the insect vector. The virus capsid, which stores all of RSV’s genetic material, competitively binds GPS2 to stop it from inhibiting the JNK activation machinery. JNK activation then promotes RSV replication in the vector, while inhibiting this pathway causes a significant reduction in virus production, therefore delaying disease outbreak in plants.”

The findings suggest that inhibiting the JNK pathway, either by lowering JNK expressions, strengthening interactions with GPS2 or weakening the effects of TNF-a, could be beneficial for rice agriculture.

“Such inhibition could be achieved through breeding or other means of genetic modification,” Wang concludes. “In some cases, it could be possible to administer the appropriate chemical compounds to rice plants to reduce the spread of RSV.”


Story Source:

Materials provided by eLifeyvtxvtcywxufvr. Note: Content may be edited for style and length.


Journal Reference:

  1. Wei Wang, Wan Zhao, Jing Li, Lan Luo, Le Kang, Feng Cui. The c-Jun N-terminal kinase pathway of a vector insect is activated by virus capsid protein and promotes viral replication. eLife, 2017; 6 DOI: 10.7554/eLife.26591

 

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From Pestnet

USDA releases proposals to fight citrus greening & diamondback moths

In the past two weeks, USDA’s Animal and Plant Health Inspection Service (APHIS) has released documents on proposals to release two genetically modified (GM) organisms: diamondback moths and a virus designed to control the citrus greening disease attacking the citrus industry.

DB moth

Diamondback moths are a global pest of cruciferous crops such as broccoli, Brussel sprouts and cabbage. On April 18, the USDA released a draft environmental assessment of a proposed experiment by a Cornell entomologist with GM diamondback moths.

The scientist, Anthony Shelton, plans to release tens of thousands of GM moths into a 10-acre vegetable field to test their potential as an “insecticide-free” control option for diamondback moths. The GM moths have been engineered to repress female survival, known as a “female autocidal trait.”

You can read the full assessment which concludes it will have no harmful effects here.

Citrus Greening
A Florida nursery, Southern Gardens Citrus Nursery, is proposing the release of a GM virus, Citrus tristeza virus, which has been engineered to express bacteria-fighting proteins found in spinach. The GM virus, which has been undergoing controlled field tests since 2010, would be grafted — not sprayed — onto citrus trees in Florida. USDA has announced its intent to launch an environmental impact statement on Southern Garden’s proposal.

source: dtnpf.com

Publication date: 4/25/2017

Diamondback moths are a global pest of cruciferous crops such as broccoli, Brussel sprouts and cabbage. On April 18, the USDA released a draft environmental assessment of a proposed experiment by a Cornell entomologist with GM diamondback moths.

The scientist, Anthony Shelton, plans to release tens of thousands of GM moths into a 10-acre vegetable field to test their potential as an “insecticide-free” control option for diamondback moths. The GM moths have been engineered to repress female survival, known as a “female autocidal trait.”

You can read the full assessment which concludes it will have no harmful effects here.

Citrus Greening
A Florida nursery, Southern Gardens Citrus Nursery, is proposing the release of a GM virus, Citrus tristeza virus, which has been engineered to express bacteria-fighting proteins found in spinach. The GM virus, which has been undergoing controlled field tests since 2010, would be grafted — not sprayed — onto citrus trees in Florida. USDA has announced its intent to launch an environmental impact statement on Southern Garden’s proposal.

source: dtnpf.com

Publication date: 4/25/2017

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Cucumber green mottle mosaic virus could have entered Queensland through imported seeds – ABC News (Australian Broadcasting Corporation)

//4654321.fls.doubleclick.net/activityi;src=4654321;type=abcne0;cat=abcne000;ord=4463444923102;~oref=http%3A%2F%2Fwww.abc.net.au%2Fnews%2F2017-05-04%2Fcucumber-green-mottle-mosaic-virus-imported-seed-biosecurity-qld%2F8494354?

Ccucumber green mottle virus could have entered Queensland through imported seeds

 

Posted 3 May 2017, 3:18pmWed 3 May 2017, 3:18pm

Biosecurity authorities are trying to figure out how a fruit and vegetable rotting disease broke out in Queensland, but have initial suspicions it was through imported seed.

Farmers from the Bundaberg region are angry cucumber green mottle mosaic virus (CGMMV) has recently been discovered on five local properties, owned by two growers.

CGMMV causes internal rot and discolouration in some cucurbit family fruit and vegetables, and its discovery comes months after an outbreak of white spot disease decimated the aquaculture industry in south-east Queensland.

Biosecurity Queensland spokesman Mike Ashton said the virus was not harmful to humans, but could ravage parts of the agriculture industry if a widespread outbreak occurs.

He said there was a possibility the virus was brought onto the infected farms by imported seeds.

That is considering the businesses operate independently and do not share personnel and equipment.

“That kind of increases the risk that perhaps it was seed that was the source of the introduction,” he said.

“It’s highly unlikely that we’ll ever be able to pinpoint exactly how it got introduced.”

“We’re certainly doing tracing investigations to try and identify the source.”

Farmers like Gino Marcon are angry there has been an outbreak of another virus, and are switching to less risky crops.

Mr Marcon normally grows a wide range of vegetables on his farm, but this year, he is only growing tomatoes to avoid CGMMV.

“We’ve actually stopped growing cucumbers, we’ve sort of got a wait-and-see attitude at the moment,” Mr Marcon said.

“We’re a bit worried that the disease may affect our zucchini production, so we’ve switched over to 100 per cent tomato production in our greenhouses.”

He blamed biosecurity authorities for the outbreak.

“We’ve lost confidence in the system and that’s the biosecurity system,” Mr Marcon said.

“We think it’s not broken, it’s shredded to bits. It’s simply not working.

“I think the whole system needs to be overhauled, we’re not getting value for money for the money being allocated to biosecurity.

“[Politicians] need to look long and hard at the whole system and change it.”

Mr Ashton rejects the allegation that the system has failed.

“We have managed to restrict the disease to a very small number of properties in Queensland,” he said.

“Unlike the Northern Territory and increasingly so in Western Australia where the disease has become quite established.”

There have been previous outbreaks of CGMMV in the Territory and WA, and an isolated case at Charters Towers in North Queensland in 2015.

Biosecurity Queensland hope the Charters Towers farm will be declared clear of the virus later this year.

The Federal Agriculture Department introduced mandatory imported seed testing to try and combat CGMMV in 2014.

In a statement, the department said it uses a sample size more than four times the size (9,400 seeds) than that used internationally (2,000).

It said that gave a high level of confidence in the results.

Topics: pest-management, rural, quarantine, crop-harvesting, agricultural-policy, vegetables, activism-and-lobbying, agricultural-crops, fruit, fruits, bundaberg-4670, qld

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From PestNet/www.pestnet.org/Grahame Jackson

PhysOrg

https://phys.org/news/2017-05-four-billion-year-old-fossil-protein-resurrected-bacteria.html

 

old virus

This figure shows two possible outcomes from a viral attempt to infect the cell. On the left, the virus binds to the bacterium, injects its genetic info, and stops because it can’t recruit the needed proteins. On the right, the virus binds to the cell, injects the genetic info, recruits the proteins, and starts replicating, resulting in the cell bursting and releasing more viruses. Credit: Jose Sanchez-Ruiz

Read more at: https://phys.org/news/2017-05-four-billion-year-old-fossil-protein-resurrected-bacteria.html#jCp

 

In a proof-of-concept experiment, a 4-billion-year-old protein engineered into modern E. coli protected the bacteria from being hijacked by a bacteria-infecting virus. It was as if the E. coli had suddenly gone analogue, but the phage only knew how to hack digital. The ancient protein, an ancestral form of thioredoxin, was similar enough to its present-day analogues that it could function in E. coli but different enough that the bacteriophage couldn’t use the protein to its advantage. The work, which could be useful in plant bioengineering, appears May 9 in Cell 

“This is an arms race. Thioredoxin has been changing in evolution to avoid being hijacked by the virus, and the virus has been evolving to hijack the protein,” says senior author Jose Sanchez-Ruiz of the University of Granada in Spain. “So we go back, and we spoil all of the virus’ strategy.”

Sanchez-Ruiz’s lab specializes in reconstructing ancient gene sequences that code for proteins. Since proteins do not preserve for billions of years, the researchers make their best estimation of the ancient protein based on genetic data across many different taxa. Thioredoxin, a versatile work-horse protein that moves electrons around so that chemical reactions in the cell can occur, is a favorite in the lab because it has been around almost since the origin of life and it is present in all modern organisms. We can’t live without it, nor can E. coli.

Thioredoxin also happens to be one of the proteins that bacteriophage must recruit to survive and replicate. Without a hijack-able thioredoxin, the virus hits a dead end. In a series of experiments led by Asunción Delgado, then a post-doc at the University of Granada, the researchers tested seven reconstructions of primordial thioredoxins, ranging in age from 1.5 billion years old to 4 billion years, to see if they could function in modern E. coli.

The old-school thioredoxins passed the test with varying degrees of success. “That was a bit surprising,” says Delgado. “The modern organism is a completely different cellular environment. Ancestral thioredoxins had different molecular partners, different everything. The farther back we get from present, the less they work in a modern organism. But even when we get back to close to the origin of life, they still show some functionality.”

But the ancestral thioredoxins were just different enough that the modern phage couldn’t recognize or bind to them.

However, resurrecting ancient proteins may be useful as more than a scientific curiosity. Virologists tend to focus on the human-infecting ones, but the viruses that kill the most people are not human pathogens but rather the viruses that kill off crops, sparking famines and mass starvation. Delgado, Sanchez-Ruiz, and their colleagues speculate that ancient proteins could be edited into plants to confer protection against crop-killing viruses. However, this idea has yet to be tested in plants.

“If this is applied to plants, it wouldn’t be genes from ancient bacteria; it would be genes from the same plant. It would be the ancestral version of a gene from the same plant,” says Sanchez-Ruiz. “This is genetic alteration, of course, but it is a mild genetic alteration. This is not like having a gene from one species being transferred to a different species. Also, this would not be like Jurassic Park. It would just be a comparatively small change in a gene that the plant already has.”

Protein resurrection experiments could also shed light on how evolution works at the protein level. “What we can do is let the virus evolve to adapt to the ancestral protein, and then do the experiment in reverse,” says Sanchez-Ruiz. “Once it’s adapted to the ancestral protein, we can test how it reacts to the modern protein. We can see if it repeats the evolution. So it would be kind of a molecular version of this Stephen J. Gould ‘replaying the tape of life’ idea.”

The researchers’ next set of experiments will focus on the fundamentals of protein evolution, but they point out that understanding and resurrecting old proteins could be a key resource for biotech. Instead of introducing new elements, bioengineers may be able to re-use older ones from earlier in viruses and cells’ co-evolutionary history. “Some people think that evolution is just a theory or is just some kind of philosophic explanation,” says Sanchez-Ruiz. “Evolutionary studies have practical applications.”

Explore further: ‘Digging up’ 4-billion-year-old fossil protein structures to reveal how they evolved

More information: Cell Reports, Delgado et al.: “Using Resurrected Ancestral Proviral Proteins to Engineer Virus Resistance” http://www.cell.com/cell-reports/fulltext/S2211-1247(17)30531-4DOI: 10.1016/j.celrep.2017.04.037

Journal reference: Cell Reports

Provided by: Cell Press

Read more at: https://phys.org/news/2017-05-four-billion-year-old-fossil-protein-resurrected-bacteria.html#jCp

 

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fresh plaza logo

Cassava viruses cause Tanzania $50m in yearly losses

The International Institute of Tropical Agriculture (IITA) said on Friday that Tanzania was losing 50 million U.S. dollars annually from viruses in cassava crops.

James Left, a principal scientist with IITA, an international research organization working across Africa to tackle hunger, poverty and malnutrition through research in agriculture, said the viruses affected half of the cassava crop produced in the east African nation.

Speaking at the 50th Anniversary of the IITA in the commercial capital Dar es Salaam, Left said almost half of all crops produced in Tanzania were affected by diseases which hugely affected the country’s agricultural sector.

Victor Mayong, IITA Eastern Africa Director, said the institute was now focusing on inventing technologies that will reduce different crop threats and ensure that the agricultural sector becomes an engine of growth.

source: news.xinhuanet.com

Publication date: 4/24/2017

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ktic_logo

BY KSRE | April 13, 2017

Kansas State University, Australian Researchers Join Forces to Combat Insect Pest

Photo courtesy of KSRE

MANHATTAN, Kan. – Researchers at Kansas State University and the University of Queensland in Australia have joined forces to attack and control a microscopic pest that can be devastating to the fruit, vegetable and flower industries.

Ralf Dietzgen, an associate professor in agriculture and food innovation at the University of Queensland, is spending three months at K-State as a Fulbright Senior Scholar in a quest to gather data and develop control measures for the small insect known as thrips.

Dietzgen is working directly with plant pathology professors Dorith Rotenberg and Anna Whitfield, who are co-directors of the Center of Excellence for Vector-Borne Plant Virus Disease Control.

Not known to grow larger than 3 millimeters, thrips are voracious eaters, using their asymmetrical mouths to puncture the surface of food crops, flowers and leaves and suck up their contents.

Of equal concern to researchers is that thrips are vectors, or carriers, of more than 20 viruses that cause plant disease, especially the tospoviruses, which also multiply in thrips. Given the right conditions, such as those found in greenhouses, thrips can reproduce exponentially and form large swarms that can transmit viruses to healthy plants.

“They’re very challenging to control, for several reasons,” Whitfield said. “For one, the insect is hard to kill. It is resistant to many insecticides. You can’t just spray crops and hope to control the spread of thrips and tospovirus.

“But secondly, the viruses that thrips can spread are very diverse and can change quickly. I call tospoviruses the influenza of the plant virus world. The predominant virus threat may change because they can switch genome segments and can develop resistance to control measures based on genetic changes. So the viruses have a lot of diversity themselves.”

Whitfield said Dietzgen’s lab in Australia is one of a few in the world that studies viruses that replicate in insects and plants.

“The thrips are a significant pest and have an impact on food security and then on top of that they transmit viruses which cause disease symptoms on the produce, like ring spots, which make them unmarketable,” Dietzgen said.

He noted that when thrips feed on flower buds, the developing fruits often become misshapen. “So you have peppers that are crooked and unmarketable,” Dietzgen said.

“We are studying thrips and the viruses they transmit at the molecular level with the goal of developing applied control strategies,” Whitfield said. “We think that better understanding the molecular mechanisms of the interaction is essential for developing sustainable control strategies for thrips and tospoviruses.”

Dietzgen recently saw first-hand the devastation that thrips-transmitted viruses can cause. One Queensland grower who provides fresh tomatoes for a large supermarket chain lost most of his crop one year due to a tospovirus transmitted by thrips. The lost crop was valued at more than $500,000.

“By the time the grower saw the disease effects, the thrips had moved on and the virus had been left behind,” Dietzgen said.

“The virus that Ralf is studying isn’t in the U.S. just yet, but thrips insects are able to move around easily so that they could appear hidden in a shipment of produce,” Whitfield said. “Any shipment of vegetables or plants that is traveling around the world could have similar pathogens and pests in it. As a control measure, we are trying to develop broad spectrum, durable resistance using different technologies.”

While Dietzgen’s stay at Kansas State University is relatively short, the researchers hope their new partnership will help lead to long-term solutions for agriculture.

“Both of our labs have generated large sets of genomic data that we’re starting to compare during my stay,” Dietzgen said. “By doing that, we hope to come up with potential targets for pest and disease control for longer term crop protection. We are asking, ‘What are the functions of these potential molecular targets and can we interfere with them?’”

Rotenberg and graduate student Derek Schneweis have compiled large sets of data outlining the messenger RNA molecules in thrips. Whitfield said their work may give new insight into how to control thrips in horticultural crops, as well as how to protect those crops from tospoviruses and other plant disease.

The prestigious U.S. Fulbright program is the largest educational scholarship of its kind, and was created after World War II by U.S. Sen. J. William Fulbright. It operates between the U.S. and 155 countries.

More than 20 Fulbright Scholarships are awarded each year to Australian students, postdoctoral researchers, academics and professionals to pursue studies or conduct research in the United States.

In 2014, Kansas State University became the first U.S. educational partner of the Australian-American Fulbright Commission. Each year since, the university has hosted Fulbright Scholars from Australia to study and collaborate with Kansas State University researchers.

Kansas State also helped form the Oz to Oz program to encourage exchanges with faculty at Australian universities, often as seminar speakers.

© 2017 Nebraska Rural Radio Association. All rights reserved. Republishing, rebroadcasting, rewriting, redistributing prohibited. Copyright Information

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From PestNet

LETHAL NECROSIS, MAIZE – MALAWI: ALERT
**************************************
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases
<http://www.isid.org>

Date: Wed 22 Mar 2017
Source: MBC Malawi [edited]
<https://www.mbc.mw/index.php/component/k2/item/3982-farmers-warned-about-maize-lethal-necrosis-disease>

Malawians have been warned to look out for maize lethal necrosis [MLN]
disease that has been attacking maize in other neighboring countries.

Johnny Masangwa, Department of Agricultural Research, said, “We are
conducting MLN survey in every district and found that the disease was
not yet in. We are carrying awareness messages as a preventative
measure to contain its spread this year [2017].” In case of an
incursion of MLN, there will be a quarantine of that area and lessons
to farmers on how to limit its spread.

[Byline: Litness Chaima]


Communicated by:
ProMED-mail
<promed@promedmail.org>

[Maize lethal necrosis (MLN) is caused by co-infection of _Maize
chlorotic mottle virus_ (MCMV, genus _Machlomovirus_, transmitted by
chrysomelid beetles) with one of several species in the family
_Potyviridae_. As synergistic partners of MCMV in MLN, _Wheat streak
mosaic virus_ (WSMV, genus _Tritimovirus_) or _Maize dwarf mosaic
virus_ (MDMV, genus _Potyvirus_) have been reported previously from
the Americas and Europe. MLN as well as MCMV were reported for the 1st
time in Africa from Kenya in 2012 (ProMED-mail post
http://promedmail.org/post/20130123.1510727). The disease is spreading
in the region where millets have also been identified as an additional
crop host being affected by MLN (ProMED-mail post
http://promedmail.org/post/20150820.3590521). _Sugarcane mosaic virus_
(SCMV) has been reported as the co-infecting virus in Sub-Saharan
Africa, but MDMV and SCMV belong to a complex of closely related
potyviruses infecting tropical grasses. Based on serology, some
strains (for example, MDMV-B) varying in host range and ability to be
seed transmitted have been reassigned between the species which has
resulted in some confusion in taxonomy.

Symptoms of the individual viruses are synergistically enhanced in MLN
and may include leaf mottling and necrosis, distortion of ears,
absence of kernels, failure to produce tassels, as well as stunting,
premature aging, and death of plants. Symptoms may disappear during
the growing season leaving plants with latent infections but reduced
yield and as virus reservoirs, making disease monitoring difficult.
While MCMV is not seed transmitted, the synergistic partner viruses
WSMV and MDMV (including some reassigned strains previously included
in SCMV) are. Thus, losses from MLN are both due to yield reductions
and trade implications resulting from the risk of virus infected seed.
Infectious vector insects may be carried by wind over long distances.
Disease management may include crop rotation, certified clean seeds,
control of vector species and weedy reservoir hosts, as well as use of
crop cultivars or hybrids with reduced sensitivity to the viruses.

The perceived high risk of a MLN incursion in Malawi, as reported
above, is entirely justified since the disease has been reported from
immediate neighbours Mozambique (ProMED-mail post
http://promedmail.org/post/20131004.1983210) and Tanzania (ProMED-mail
post http://promedmail.org/post/20130403.1620327). While it is being
reported that surveys have not detected the disease in the country as
yet, it is not stated which survey methods were used. If surveys were
only conducted from symptoms and/or without molecular diagnosis on
samples, MLN may well be present already in Malawi but has remained
undetected.

Maps
Malawi:
<http://nthambazale.com/wp-content/uploads/2009/05/malawi_map.gif>
and
<http://healthmap.org/promed/p/176>
Africa, overview:
<http://www.worldatlas.com/webimage/countrys/africa/maps/africa.jpg>

Pictures
Maize lethal necrosis:
<http://cabiplantwise.files.wordpress.com/2013/04/maize-lethal-necrosis.jpg>
and
<https://iapps2010.files.wordpress.com/2017/01/9f498-maize.jpg>
Symptoms of MCMV, SCMV and MDMV single infections in maize via:
<http://maizedoctor.org/image-galleries/viral-diseases>

Links
Information on maize lethal necrosis:
<http://www.fao.org/fileadmin/user_upload/emergencies/docs/MLND%20Snapshot_FINAL.pdf>,
<http://mfarm.co.ke/blog/post/Maize-Lethal-Necrosis-MLN-Signs-and-Precautions>,
<http://www.plantwise.org/knowledgebank/datasheet.aspx?dsid=119663>,
and
<http://apsjournals.apsnet.org/doi/full/10.1094/PHYTO-12-14-0367-FI>
Information on MCMV:
<http://www.dpvweb.net/dpv/showdpv.php?dpvno=284> and
<http://www.plantwise.org/knowledgebank/datasheet.aspx?dsid=32129>
Information on MDMV:
<http://www.dpvweb.net/dpv/showdpv.php?dpvno=341>,
<http://www.plantwise.org/knowledgebank/datasheet.aspx?dsid=8157>,
and
<http://maizedoctor.org/pests-diseases/list/12-english/pests-and-diseases/395-maize-dwarf-mosaic-virus>
Information on SCMV:
<http://www.dpvweb.net/dpv/showdpv.php?dpvno=342>,
<http://www.plantwise.org/knowledgebank/datasheet.aspx?dsid=49801>,
and
<http://maizedoctor.org/pests-diseases/list/12-english/pests-and-diseases/416-sugarcane-mosaic-virus>
Virus taxonomy via:
<http://ictvonline.org/virusTaxonomy.asp?version=2016>
– Mod.DHA]

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