Archive for the ‘Fungi’ Category

Weird year for Sicilian citrus fruit

“Citrus fruit production this year is quite low, especially for oranges. Producers not only had to deal with the CTV-Citrus Tristeza Virus, but also with a whole lot of other factors – mild temperatures during the past winters, lower blossoming, wider yield alternance. In addition, it rained a lot in September,” reports Corrado Vigo, agronomist and President of the Ordine dei Dottori Agronomi e dei Dottori Forestali in Catania.

For what concerns the rain/drought, Vigo explains that “I have noticed these events are cyclical, they occur every 10-11 years. What is weird is that this cycle coincides with the Sun cycle. We are expecting some more rain in December as well.”

In addition to the weather conditions, there is a series of fungi, pathogens and Phytophthora that, with the temperatures registered so far, spread. “For example, the persistent rain in September triggered Phytophthora citrophthora, which led to a loss of fruit. In addition, in October, there was a late attack of Ceratitis capitata“.

There are a lot of drops of yet unripe oranges as well as a lot of mouldy fruit on the trees. The areas of Scordia, Lentini, Palagonia and Mineo were affected by dessicating wind, which damaged both the fruit and the leaves. “We already expected a drop in volumes, but now they will be even lower.”

Varietal innovation
“There are very few innovative varieties. Producers are looking to replace the trees (especially because of the Citrus Tristeza Virus), but costs are high. The last PSR call for bids, for example, ended in 2012 and the new one hasn’t opened yet. If we consider that, last year, oranges sold at 4 cents, we can see how it might be difficult to end the year positively, let alone make investments.”

We must also keep in mind that orchard response times are slow. “We are talking about seven/eight years for a full production cycle. Another problem is the availability of plants. In Sicily, we generate around 1.5/2 million plants. To reconvert the areas affected, 24-25 million plants are needed and it would take 12-13 years.”

“Just like every year, our citrus fruit is available on the market as well as oranges from Spain and grapefruit from Israel, for example.”
“I keep thinking about the French, who only buy produce made in France before anything else. Only then do they look for something foreign. In Italy, it seems as if we welcome foreign produce.”

Corrado Vigo
Email: corrado@vigo.it
Web: www.vigo.it


Publication date: 12/8/2016

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New GMO could protect wheat and barley against deadly blight



Fusarium head blight (FHB), caused by Fusarium graminearum, is a devastating disease of wheat and barley that leads to reduced yield and mycotoxin contamination of grain, making it unfit for human consumption. FHB is a global problem, with outbreaks in the United States, Canada, Europe, Asia and South America. In the United States alone, total direct and secondary economic losses from 1993 to 2001 owing to FHB were estimated at $7.67 billion1. Fhb1 is the most consistently reported quantitative trait locus (QTL) for FHB resistance breeding. Here we report the map-based cloning of Fhb1 from a Chinese wheat cultivar Sumai 3. By mutation analysis, gene silencing and transgenic overexpression, we show that a pore-forming toxin-like (PFT) gene at Fhb1 confers FHB resistance. PFT is predicted to encode a chimeric lectin with two agglutinin domains and an ETX/MTX2 toxin domain. Our discovery identifies a new type of durable plant resistance gene conferring quantitative disease resistance to plants against Fusarium species.

The GLP aggregated and excerpted this blog/article to reflect the diversity of news, opinion, and analysis. Read full, original post: Wheat Fhb1 encodes a chimeric lectin with agglutinin domains and a pore-forming toxin-like domain conferring resistance to Fusarium head blight

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University of Guelph plant scientists have shown for the first time how an ancient crop teams up with a beneficial microbe to protect against a devastating fungal infection, a discovery that may benefit millions of subsistence farmers and livestock in developing countries.

Their discovery may also point the way toward a natural treatment to thwart the pathogen in other important crops grown worldwide including corn and wheat, said plant agriculture professor Manish Raizada.

He’s senior author of a paper published in Nature Microbiology. He worked with lead author and former PhD student Walaa Mousa, current graduate student Charles Shearer, Ridgetown Campus scientist Victor Limay-Rios and researchers in California.

The paper describes a novel defence mechanism allowing crop plants to work with bacteria called endophytes living in their roots to ward off Fusarium graminearum. This fungus makes a toxin that can sicken livestock and people.

The M6 microbe lives in the roots of finger millet, a cereal crop grown by subsistence farmers in Africa and South Asia. Millions of people rely on the crop, first domesticated in East Africa in about 5,000 BC.

The crop has long been known to be resistant to fungal disease. Through microscope observations, Mousa learned how the mechanism works. Sensing the pathogen near the plant roots, the microbe enters the soil and multiplies to millions of cells that form a protective barrier on the root surface.

Even more striking, he said, the plant’s root hairs grow to many times their normal length. Like layers in lasagna, the root hairs and the bacterial cells form a dense mat that traps the fungus.

Mousas found that natural products of these endophytic bacteria then kill the fungus. Raizada said, “This appears to be a new defence mechanism for plants.” He likens the mechanism to the human immune system, with immobile plant cells “recruiting” mobile microbes to seek out and destroy pathogens.

The researchers believe this mechanism evolved in a kind of evolutionary arms race in the African ancestors of finger millet and Fusarium. The fungus can make an antibiotic against M6 for which the bacterium has developed resistance in turn, Raizada said.

“We think subsistence farmers in East Africa over generations may have selected for this special microbe through breeding.”

He said the findings may help agricultural companies develop seed treatments using M6 to protect more susceptible and widely grown crops such as corn and wheat against the fungus.

Farmers spend tens of millions of dollars fighting crop diseases such as Fusarium.

U of G has licensed the lab’s results to an agricultural startup company for potential use in those crops. The microbe is now being tested in Canadian corn and wheat. The team found that M6 also protects against other fungi.

He said the study shows the importance of indigenous farming knowledge and practices. “These crops should be explored and valued.”

Read the paper: Root-hair endophyte stacking in finger millet creates a physicochemical barrier to trap the fungal pathogen Fusarium graminearum.

Article source: University of Guelph

Image credit: University of Guelph

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Researchers develop strategy that could lead to environmentally friendly fungicide to fight pathogens that cause billions of dollars in crop loss

gray mold on fruit, vegetables and flowersThe images third from the bottom and at the bottom show fruit, vegetables and flowers treated with pathogen gene-targeting RNA molecules. The other images represent various control methods.


RIVERSIDE, Calif. (www.ucr.edu) — Have you ever bought strawberries or other fruits and vegetables, forgot to put them in the refrigerator and later noticed they had gray mold on some of them?

That’s Botrytis cinerea, a fungal pathogen that can infect more than 1,000 plant species, including almost every fruit and vegetable and many flowers. Wine grapes are also a notable host – in grapes the condition is known as bunch rot. It causes billions of dollars in crop loss annually.

A team of researchers, led by Hailing Jin, a University of California, Riverside professor of plant pathology and microbiology, have developed a new strategy that could provide an easy-to-use and environmentally friendly fungicide to fight B. cinerea and other fungal pathogens that harm crops.

The findings were just published in the journal Nature Plants.

These findings build on a paper by Jin’s group published in 2013 in the journal Science. In that paper, they outlined how they discovered the mechanism by which B. cinerea infects plants.

Many pathogens secrete protein effectors molecules to manipulate and – eventually – compromise host immunity. The researchers, led by Jin, found three years ago for the first time that B. cinerea can deliver small RNA effector molecules to the host cells to induce cross-kingdom RNA interference (RNAi) to suppress host immunity.

Building on that work, in the just-published study in Nature Plants, they discovered that such cross-kingdom RNAi is bidirectional, meaning small RNAs can flow from the pathogen to the host and from the host to the pathogen.

Furthermore, they found that B. cinerea is capable of taking up RNA molecules from the environment, which makes it possible to use such external RNAs in fungicidal sprays to manage diseases.

The researchers tested that idea and found that applying those pathogen gene-targeting RNA molecules to the surface of fruits and vegetables and flowers – they used tomato, strawberry, grape, lettuce, onion, and rose – can control gray mold diseases.

The findings outlined in the Science and Nature Plants papers have significant implications for farmers looking to control fungal pathogens. Currently, fungicides and chemical spraying are still the most common disease control strategy. But, these treatments pose serious threats to human health and environments. RNA, which is present in all living organisms, doesn’t present problems for human health and it naturally degrades in soil.

While the research focused on the fungal pathogens B. cinerea and Verticillium dahliae, another fungal pathogen that causes wild disease on dozens of trees, shrubs, vegetables, and fields crops, the researchers believe this RNAi-based technique could be used to control multiple pathogens at the same time.

While the research focused on the fungal pathogen B. cinerea, the researchers believe the technique could be used to control other fungal pathogens, such as Verticllium dahliae, which causes wild disease on dozens of trees, shrubs, vegetables, and fields crops.

It also has the potential to decrease the use of GMOs by providing an effective, environmentally friendly way to control plant diseases.

The Nature Plants paper is called “Bidirectional cross-kingdom RNAi and fungal uptake of external RNAs confer plant protection.” In addition to Jin, the authors are Ming Wang and Arne Weiberg, both of UC Riverside; Arne Weiberg, who recently got a faculty position at the University of Munich; Feng-Mao Lin and Hsien-Da Huang, both of National Chiao Tung University in China; and Bart P. H. J. Thomma of Wageningen University in the Netherlands.

This research was supported by grants Jin received from the National Science Foundation and National Institutes of Health.

The invention has a patent pending status.


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Sudden drop in disease resistance in SA chickpea crop raises concern

Updated Mon at 11:16pm

A sudden loss of disease resistance in the expected bumper chickpea crop in South Australia this year is raising concerns.

South Australian Research and Development Institute (SARDI) pathologist Dr Jenny Davidson said she was concerned about the level of infection in varieties thought to be resistant to the disease.

Authorities have approved minor use permits for farmers to use chemicals to spray their crops to limit the spread of ascochyta blight.

Ascochyta blight has been detected in several cropping regions over the past few weeks — including the Mid North, Lower North and Yorke Peninsula.

Dr Davidson said not only was the extent of the disease concerning, but so too the pace of the outbreak had been unexpected.

“Suddenly this year, which we assume is to do with the rain in winter, the disease is creating some really severe problems.

“This sudden loss of resistance is something that is a little bit surprising, [given] the speed with which it has happened.”

“We were aware that something was changing and we gave information out to industry last year to monitor their crops because something was changing.

“But suddenly we’ve got a dramatic shift in the whole spectrum of what’s going on.”

Scientists are urging farmers to get on top of the outbreak as soon as possible, and by doing this farmers can help reduce its severity.

“If they get out there and spray their fungicides, and continue to put out sprays, they should be able to get those crops through.

Dr Davidson said to use protectant fungicides ahead of rain fronts, starting at the next rain front.

“They need to get a fungicide spray out, then during podding. They really need to be very diligent about getting those sprays on the crops,” Dr Davidson said.

Topics: agricultural-crops, agricultural-chemicals, earth-sciences, port-pirie-5540

First posted Mon at 10:56pm


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Communicated by:

Growers say the fungal disease is piling on their miseries brought about by distribution of substandard fertiliser that affected germination of the crop

Wednesday August 17 2016

Mr Jeremiah Kipyego inspects maize on his farm in Uasin Gishu County in May.

Mr Jeremiah Kipyego inspects maize on his farm in Uasin Gishu County in May. Maize farmers in the region expressed fears of yield decline this season due to attack by head smut disease. FILE PHOTO | NATION MEDIA GROUP 

In Summary

  • Growers expressed fears of serious yield decline this season due to the disease referred to as head smut.
  • Maize farmers asked to practice crop rotation to break the cycle of the fungal disease.
  • The fungal attack follows repeated outbreak of Maize Lethal Necrosis (MLN) disease that ravaged parts of the country last season, forcing some farmers to uproot the crop.
  • Maize production in Rift Valley dropped from 21 million bags to 16 million bags last season due to erratic rainfall pattern and repeated outbreak of MLN disease.

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An outbreak of a maize disease has left many farmers in the North Rift uncertain of their harvests putting the country’s food security at risk.

Growers yesterday expressed fears of serious yield decline this season due to the disease referred to as head smut, which is adding to the miseries bought about by distribution of sub-standard fertiliser that affected germination patterns of maize.

“We are worried that fungal disease will add to the miseries of high cost of production, rendering agriculture a non-profit investment,” said Mr Patrick Kemboi from Chepkumia, Nandi County.

The disease has been reported in parts of Uasin Gishu, Nandi  and Elgeyo Marakwet County.

Maize producers are now accusing the Kenya Seed Company of supplying them with poor seeds that has led to the outbreak of the fungal disease.

“I wonder why our crop has been attacked yet I planted certified seed from the company sourcing from the Kenya Seed Company,” said Mr Wilson Sang from Chembulet, Uasin Gishu County.

Growers have taken issue with the Kenya Seed management due to alleged failure in cracking down on traders dealing in sub-standard planting materials.

“Poor quality seed and a failure to crack down on fake seed being supplied by Kenya Seed’s accredited stockists,” said Mr Andrew Rotich, a maize farmer from Cherang’any.

Kenya Seed managing director Azariah Soi has, however denied responsibility for the outbreak of the fungal disease saying that studies conducted in conjunction with the Kenya Plant and Health Inspectorate Services (Kephis) have shown that the head smut disease has nothing to do with seed.


“The head smut disease that has affected maize in Rift Valley is not as a result of seed distributed by our company,” said Mr Soi noting that the disease was in the soil.

He asked maize farmers to practice crop rotation to break the cycle of the fungal disease. “Our researchers are working closely with those from Kephis to come up with further remedies that can be employed by farmers in future including a possible production of seeds, which are disease-resistant,” Mr Soi said.

The fungal attack follows repeated outbreak of Maize Lethal Necrosis (MLN) disease that ravaged parts of the country last season, forcing some farmers to uproot the crop.

“The recurrence of MLN disease and attack of the crop by head smut is a serious challenge to maize cultivation,” said Mr Isaac Kibogy from Sergoit, Uasin Gishu County.

Farmers have been asked to implement crop rotation to break the cycle of the disease that damaged over 260,000 hectares of maize valued at Sh2 billion in Rift Valley last season.

“Feeding the plants to cattle is not appropriate because the fungus which cannot be digested is passed out through dung and later reproduces posing threat to crops again,” said Mr Soi.

Maize production in Rift Valley dropped from 21 million bags to 16 million bags last season due to erratic rainfall pattern and repeated outbreak of MLN disease.

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From PestNet@yahoogroups.com

This is a summary of the research at UC Davis that the other email was referring to. It would have been better to have put both out together …

Crop Biotech Update

Banana Fungus DNA Unravelled; Findings to Lead to Hardier Bananas

Researchers at the University of California Davis and Wageningen UR have unravelled the DNA of Pseudocercospora fijiensis, the fungus that causes black Sigatoka disease in bananas globally.

The Sigatoka complex’s three fungal diseases — yellow Sigatoka (P. musae), eumusae leaf spot (P. eumusae) and black Sigatoka (P. figiensis) — emerged as destructive pathogens in the last century. Eumusae leaf spot and black Sigatoka are now the most devastating, with black Sigatoka posing the greatest constraint to banana production worldwide. Farmers need to apply fungicide at least 50 times per year to control the disease.

UC Davis plant pathologist Ioannis Stergiopoulos and colleagues sequenced the genomes of eumusae leaf spot and black Sigatoka, and compared their findings with the previously sequenced yellow Sigatoka genome sequence. They discovered that Sigatoka Complex has become lethal to banana plants not just by shutting down the plant’s immune system, but also by adapting the metabolism of the fungi to match that of the host plants. As a result, the attacking fungi can produce enzymes that break down the plant’s cell walls, allowing the fungi to feed on the plant’s sugars and other carbohydrates.

For more details, read the news release at the UC Davis website.

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