Archive for the ‘Fungi’ Category

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Australian scientists work to save the banana with fungus resistance trials

A slippery skid awaits the banana if the hazard is not removed. So in a field near Humpty Doo in Australia’s Northern Territory, scientists are racing to begin an experiment that could determine the future of the world’s most popular fruit.
Researchers will soon place into the soil plants that they hope will produce standard Cavendish bananas – the curved, yellow variety representing 99 per cent of all bananas sold in the United States.
The plants have been modified with genes from a different banana variety.
A fungus known as fusarium wilt has wiped out tens of thousands of hectares of Cavendish plantations in Australia and South-east Asia over the past decade and recently gained a foothold in Africa and the Middle East.
Scientists said Latin America, the source of virtually all the bananas eaten in the US, is next.
“These recent outbreaks confirmed that this thing does move,” said plant pathologist Randy Ploetz of the University of Florida, who identified the fungus in 1989 in samples from Taiwan.
Ever since, farmers have been trying to escape the effects of fusarium wilt, also known as Panama disease Tropical Race 4, or TR4. Once it hits a farm, the only recourse is to eradicate the plants and start over.
Ironically, a major obstacle to replacing today’s Cavendish with a TR4-resistant strain is the industry, which, for the most part, has dropped out of doing research, said Prof Ploetz. The result is that very few scientists have been focusing on the problem directly.
This means that even if Prof Dale’s transgenic experiment in Humpty Doo is successful, the TR4 fungus’ march to Latin America may be inevitable.

Publication date: 10/13/2017

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Randy Gardner Dilip Panthee Tomatoes Dee Shore/North Carolina State University
North Carolina State University tomato breeders Dilip Panthee and Randy Gardner.

Breeding a better tomato

North Carolina State University scientists are breeding flavorful and disease-resistant tomatoes for farmers and home gardeners.

Dee Shore | Aug 22, 2017

With some 700 varieties grown around the world, tomatoes come in an array of colors, shapes and sizes. To take advantage of that variety, two North Carolina  State University scientists are breeding more flavorful and disease-resistant types for farmers and home gardeners alike.

NC State’s tomato breeding program focuses on developing tomatoes especially suited for North Carolina’s growing conditions, from the mountains to the coast. Based at the Mountain Horticultural Crops Research and Extension Center near Asheville, the program has yielded more than 30 hybrids, including some of the most widely grown types in the eastern United States.

The breeders, Randy Gardner and Dilip Panthee, have even more varieties on the way.

Panthee’s efforts focus on developing better commercial varieties for the fresh market, while Gardner is producing new breeding lines and hybrid varieties derived from heirloom tomatoes – ones that are open-pollinated, with seeds passed down from one generation to the next. They are prized for their flavor and come in a wide variety of fruit colors, sizes and shapes.

Gardner founded the breeding program in 1976, as North Carolina tomato producers struggled to deal with a devastating disease known as verticillium wilt. Nearly every variety he has developed has resistance to that disease, and some have resistance to multiple viral and fungal diseases that have popped up over the years.

Gardner, now a professor emeritus in NC State’s Department of Horticultural Science, retired in 2008, but he hasn’t stopped breeding tomatoes.

“I plan soon to release several hybrids of different fruit colors in the heirloom-type tomatoes. These are ones bred primarily for late-blight resistance. Most people are familiar with red tomatoes, and a lot of people won’t eat a tomato unless it’s red, but there are other colors, many with their own distinct flavor profiles and fruit texture,” he said, pointing to yellow, orange, pink, purple, and even striped tomatoes he’s grown in a research station greenhouse and tested in research station and grower trials.

Since 2008, Gardner has worked side by side with Panthee in the greenhouse. Like Gardner, Panthee has had success with breeding varieties resistant to a range of diseases. He’s also focused on traits such as flavor and levels of lycopene, an antioxidant that appears to have health benefits.

Panthee came to NC State with a passion for tomatoes that he gained during the early part of his career as a breeder in Nepal. He also brought experience in molecular marker-assisted breeding, a technique that can cut the amount of time it takes to produce a new hybrid. It involves looking for sequences of nucleotides, or markers, that make up a segment of DNA near the genes of interest; if a young plant doesn’t have that DNA segment, the breeder can discard the plant, focusing only on those that do have the genes.

In the breeding pipeline, Panthee has several hybrids with multiple disease resistance that he’s close to releasing. While farmers could rely on chemicals for disease control, that raises their production costs. Having resistant varieties is also important to home gardeners and others interested in growing tomatoes organically.

North Carolina is the nation’s fourth-leading state when it comes to fresh market tomato production, and one of Panthee’s goals is to continue developing varieties that will make the industry even more competitive.

“I see a very good potential to exploit the geographical and climatic variation that exists in North Carolina,” he said. “We have to grab the market that exists here in North Carolina and niches in other states, as well.”

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ftf logo-feed-the-future

University Innovations Cross Borders to Deliver Impact

August 3, 2017
Photo by Amer Fayad-  Farmers in Nepal prepare seedling trays using coconut pith and the beneficial fungus Trichoderma.

Bangladesh and Nepal are so close they could touch, if not for the small sliver of India between them. The three countries share more than proximity: Thanks to the Feed the Future Innovation Lab for Integrated Pest Management, they also share technologies and research that help them grow better food and increase agricultural productivity.

For many years, agriculture has made huge advances because of research, helping farmers and food producers boost yields, produce more nutritious and safe food, and keep up with agricultural demand. Through 24 U.S. university-led Feed the Future Innovation Labs, Feed the Future supports research that combats emerging threats.

Often, this important work spans borders.

In 1998, the Feed the Future Innovation Lab for Integrated Pest Management began working in Bangladesh and expanded its work to India and Nepal in 2005. While the Innovation Lab no longer has projects in India, the innovations it developed there are now helping address agricultural challenges in neighboring countries.

“Crop pests and diseases don’t care about borders,” said Muni Muniappan, director of the Integrated Pest Management Innovation Lab. “So we also share technologies across borders.”

One of the biggest successes to come out of this three-country partnership is the use of Trichoderma, a fungus that fights diseases, promotes plant growth, and is safe to handle. Researchers from the Innovation Lab previously worked with Tamil Nadu Agricultural University in India, which had been producing and selling Trichoderma to farmers. Once researchers learned about its benefits, they began promoting its production and use in Bangladesh and Nepal.

Trichoderma has been a godsend in treating fungal diseases in developing countries,” Muniappan said. “It is easy and cheap to produce, very effective against pests, and in addition to helping farmers regain their livelihood, it has created a new source of income.”

In India, the commercial production of Trichoderma was so successful that Tamil Nadu Agricultural University built a new plant pathology building out of the money it made from the sale of the fungus. It is also an asset to vendors. In Nepal, entrepreneurs are making a living selling the fungus, based in part on trainings they received through the Innovation Lab. And in Bangladesh, Trichoderma is mixed with compost and applied in the field to combat soilborne diseases of vegetable crops.

Another technology developed in India and implemented successfully in Bangladesh and Nepal is the use of coconut dust to help raise seedlings. Coconut dust, previously considered a waste material, provides an ideal medium in which to grow healthy, young seedlings until they’re ready to be transplanted. Producing the seedling trays creates jobs, especially for women. They often earn valuable extra income doing this work, which they can invest in their families.

The Innovation Lab has disseminated other technological innovations and approaches throughout the three countries, like grafting vegetable shoots, using pheromone traps, and making bio-pesticides. To help rural farmers access and understand these tools and improved practices, the Innovation Lab is not only working through the usual channels of extension agents, NGOs, and development projects, but also by helping local, small-scale industries produce and market the recommended products to those that need them most.

Continuing their work to connect researchers from across the world, the Innovation Lab facilitates the transfer of vital technologies by organizing travel opportunities for Bangladeshi and Nepali farmers, scientists, and entrepreneurs to visit Indian universities and bio-pesticide companies. They also arrange for Indian scientists to visit Bangladesh and Nepal to host scientific workshops to share knowledge.

In 2016, five representatives from Bangladesh’s leading agribusiness firms traveled to India to visit nurseries, attend university lectures, and see a bio-fertilizer lab.

The connections made between India, Bangladesh and Nepal have led to increased crop production, a reduction in health and environmental damage, and an economic benefit to local farmers and agri-business entrepreneurs. They are also a valuable opportunity for developing countries to profit and learn from one another

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From PestNet

A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases

Date: Sat 22 Jul 2017 12:13 AM IST
Source: Greater Kashmir [edited]

A disease diagnostic visit was carried out by a team of experts to
affected paddy fields at Budgam and Chadoora sub divisions [of Budgam
district]. The observations include that at all the places the paddy
fields were found affected with rice blast disease. “As enquired from
farmers, no disease management practice was adopted in the affected
fields. Disease incidence ranging from 10 to 30 per cent and intensity
of 3.5 to 17.6 per cent was recorded in China varieties,” [a
spokesperson] added.

The probable causes of [the] outbreak, as per experts, are:
cultivation of varieties susceptible to blast, use of own saved seed,
no management practice applied. The team has recommended immediate
spray of [fungicide].

Communicated by:

[Rice blast is caused by the fungus _Pyricularia oryzae_ (synonym
_Magnaporthe oryzae_). It is one of the most destructive diseases of
the crop worldwide, with potential yield losses of more than 50 per
cent. Symptoms include lesions on all parts of the shoot, as well as
stem rot and panicle blight. When nodes are infected, all plant parts
above the infection die and yield losses are severe. When infection
occurs at the seedling or tillering stages, plants are often
completely killed. Depending on which plant parts are affected, the
disease may manifest itself as leaf, collar, node, or neck blast. More
than 50 species of grasses and sedges can be affected by related
pathogens, but most strains isolated from rice can only infect a
limited number of cultivars.

The fungus also causes wheat blast (for example, see ProMED-mail posts
http://promedmail.org/post/20170306.4883233 and
http://promedmail.org/post/20170123.4784298). Although the pathogens
are currently classified as the same species, the wheat blast pathogen
is a distinct population (referred to as _P. oryzae_ Triticum
population) and does not cause disease in rice.

Symptom severity and spread of the blast fungus are influenced by
climatic conditions. The disease is also favoured by high nitrogen
levels (for example from fertilisers) and high humidity. The fungus is
spread with infected plant material (including seed), by mechanical
means (including insect activity), water and wind. Disease management
may include fungicides and cultural practices but relies mainly on
resistant varieties. However, the fungus is highly variable and this
favours the emergence of new strains with increased virulence. Use of
certified clean seed is essential, and farm saved seed, as mentioned
above, would pose a high risk of carry-over of the fungus to
subsequent crops.

Kashmir has been using rice cultivars from China for a long time. The
pathogen strains in that area have been shown to be more closely
related to Chinese and Japanese variants than to other Indian ones
(ProMED-mail post http://promedmail.org/post/20160407.4145967). This
would indicate that these strains were imported into Kashmir together
with the host and that resistant rice cultivars developed in China or
Japan may be a useful resource for developing resistant varieties
suitable for Kashmir.

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Development of Powdery Mildew Resistant Tomato via CRISPR-Cas9

In tomato (Solanum lycopersicum), there are sixteen Mlo genes, with SlMlo1 being the major contributor to the susceptibility to the powdery mildew caused by Oidium neolycopersici. Natural loss-of-function slmlo1 mutants are available in tomato, however, introgression of such mutations is a lengthy process. The team of Vladimir Nekrasov from the Sainsbury Laboratory, Norwich Research Park in the UK aimed to generate a transgene-free genetically edited slmlo1 tomato using the CRISPR-Cas9 system.

The team targeted the SlMlo1 locus using the double sgRNA strategy. Transformants were analyzed and eight out of ten tested T0 transformants indicated the presence of mutations. Assays using the powdery mildew fungus revealed that all the generated T0 slmlo1 mutant plants were resistant to the pathogen, while wild-type plants were susceptible.

Furthermore, the slmlo1 mutant plants were morphologically similar to the wild type and also produced harvested fruit weight similar to the wild types. The team named the generated variety Tomelo. This study presents evidence for CRISPR-Cas9 being a highly precise tool for genome editing in tomato.

For more on this study, read the article in Nature.

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Invasive myrtle rust disease discovered on mainland NZ

Published: 5 May 2017

The Ministry for Primary Industries (MPI) has confirmed the presence of the myrtle rust plant disease on mainland New Zealand for first time, in Kerikeri.

MPI and Auckland Council are asking Aucklanders to keep their eyes peeled for this invasive fungus and to report it immediately if spotted.

Councillor Penny Hulse, Chair of council’s Environment and Community Committee says the find is extremely worrying and vigilance is needed.

“It’s very early days and we know that MPI are doing everything in their power to prevent the spread of this disease. Council’s biosecurity staff are standing by to assist MPI if needed.

“In the meantime we can all add to the effort by keeping myrtle rust top of mind when we are outdoors over the coming weeks and months. If you think you’ve seen it in Auckland, please call MPI straight away.”

What is myrtle rust disease?

Myrtle leaf rust is a serious fungal disease that attacks members of the myrtle family of plants.

It could have a serious impact on our native pohutukawa, manuka, kanuka and rata as well as feijoa and eucalypts, damaging or even killing them.  Myrtle rust spores are microscopic and can easily spread across large distances by wind, or via insects, birds, people, or machinery.

What does it look like?

You’re most likely to spot myrtle rust on young, soft, actively growing leaves, shoot tips and young stems, as well as flowers and fruit.

Initial symptoms are powdery, bright yellow or orange-yellow spots, or brown-grey rust pustules in the case of older infections. The rust can appear red depending on the types of spores being produced.

The fungus often causes leaves to buckle or twist and die off.

What should I do if I spot it?

Report it immediately to the Ministry for Primary Industries (MPI) on 0800 80 99 66.

Do not touch the fungus or try and take samples as this will increase the risk of it spreading. Note down its location and take photos if possible.

Visit the Ministry of Primary Industries (MPI) for more information.

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AUT Student Journalism

Team effort to fight threatening fungal plant disease


Ashleigh Martin April 8, 2017

<!– Ashleigh Martin –>

Team effort to fight threatening fungal plant disease

Look out for yellow powdery eruptions on leaves. Photo: Supplied / M Daughtrey, Cornell University

The Ministry of Primary Industries has issued a call to arms after a fungal plant disease which could affect New Zealand native plants and our honey industry was found on Raoul Island.

The disease, myrtle rust, can be identified by bright yellow powdery eruptions on leaves and attacks various species of plant such as pōhutukawa, kānuka, mānuka and non-natives like the feijoa plant.

Amid fears the disease could spread to these shores, MPI is working with DOC and the New Zealand Defence Force to survey Raoul for it.

David Yard, MPI incident controller, said several DOC workers were going over the island, so a joint plan could be made.

“They’ve been briefed on how to minimise the risk of spreading it…because obviously the risk is if you work through an affected area, you might actually spread the disease,” Mr Yard said.

Raoul Island is 1100km away from the nearest part of the New Zealand mainland. The island is also very rocky and mountainous, making work difficult.

“We’ve been working with the Defence Force should we need to get materials, equipment and people onto the island to support DOC efforts,” Mr Yard said.

The disease can travel long distances by wind and can also be transported by insects, rain splashes and contaminated clothing.

The Wellington-based Science Media Centre quoted Dr David Teulon, director of Better Border Biosecurity, who said myrtle rust had been spreading rapidly around the world in recent years.

“If it reached mainland New Zealand, it could have a serious impact on a number of our taonga Māori plant species, such as pōhutukawa and rātā, with severe infections causing plants to die,” Dr Teulon said.

“Plants that are also important to our honey industry, such as mānuka and kānuka, could also be affected, which could severely impact on New Zealand’s annual $300 million of honey exports.”

– See more at: http://www.tewahanui.nz/environment/team-effort-to-fight-threatening-fungal-plant-disease#sthash.vF0oxCzv.dpuf

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