Grahame Jackson posted a new submission ‘A single laccase acts as a key component of environmental sensing in a broad host range fungal pathogen’

Saturday, 23 March 2024 08:16:28

PestNet

Submission

A single laccase acts as a key component of environmental sensing in a broad host range fungal pathogen

Nature

• Nathaniel M. Westrick, 
• Eddie G. Dominguez, 
• Madeline Bondy, 
• Christina M. Hull, 
• Damon L. Smith & 
• Mehdi Kabbage 

Communications Biology volume 7, Article number: 348 (2024) 

Abstract

Secreted laccases are important enzymes on a broad ecological scale for their role in mediating plant-microbe interactions, but within ascomycete fungi these enzymes have been primarily associated with melanin biosynthesis. In this study, a putatively secreted laccase, Sslac2, was characterized from the broad-host-range plant pathogen Sclerotinia sclerotiorum, which is largely unpigmented and is not dependent on melanogenesis for plant infection. Gene knockouts of Sslac2 demonstrate wide ranging developmental phenotypes and are functionally non-pathogenic. These mutants also displayed indiscriminate growth behaviors and enhanced biomass formation, seemingly as a result of their inability to respond to canonical environmental growth cues, a phenomenon further confirmed through chemical stress, physiological, and transcriptomic analyses. Transmission and scanning electron microscopy demonstrate apparent differences in extracellular matrix structure between WT and mutant strains that likely explain the inability of the mutants to respond to their environment. Targeting Sslac2 using host-induced gene silencing significantly improved resistance to S. sclerotiorum, suggesting that fungal laccases could be a valuable target of disease control. Collectively, we identified a laccase critical to the development and virulence of the broad-host-range pathogen S. sclerotiorum and propose a potentially novel role for fungal laccases in modulating environmental sensing.

Read on: https://www.nature.com/articles/s42003-024-06034-7

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Saturday, 23 March 2024 08:16:28

Grahame
Jackson posted a new submission ‘A single laccase acts as a key component of
environmental sensing in a broad host range fungal pathogen’

Submission

A single laccase acts as a key component of environmental sensing in a
broad host range fungal pathogen

Nature

• Nathaniel M. Westrick, 
• Eddie G. Dominguez, 
• Madeline Bondy, 
• Christina M. Hull, 
• Damon L. Smith & 
• Mehdi Kabbage 

Communications
Biology volume 7,
Article number: 348 (2024) 

Abstract

Secreted laccases are important enzymes on a broad ecological scale for
their role in mediating plant-microbe interactions, but within ascomycete fungi
these enzymes have been primarily associated with melanin biosynthesis. In this
study, a putatively secreted laccase, Sslac2, was characterized
from the broad-host-range plant pathogen Sclerotinia sclerotiorum,
which is largely unpigmented and is not dependent on melanogenesis for plant
infection. Gene knockouts of Sslac2 demonstrate wide ranging
developmental phenotypes and are functionally non-pathogenic. These mutants
also displayed indiscriminate growth behaviors and enhanced biomass formation,
seemingly as a result of their inability to respond to canonical environmental
growth cues, a phenomenon further confirmed through chemical stress,
physiological, and transcriptomic analyses. Transmission and scanning electron
microscopy demonstrate apparent differences in extracellular matrix structure
between WT and mutant strains that likely explain the inability of the mutants
to respond to their environment. Targeting Sslac2 using
host-induced gene silencing significantly improved resistance to S.
sclerotiorum, suggesting that fungal laccases could be a valuable target of
disease control. Collectively, we identified a laccase critical to the
development and virulence of the broad-host-range pathogen S.
sclerotiorum and propose a potentially novel role for fungal laccases
in modulating environmental sensing.

Read on: https://www.nature.com/articles/s42003-024-06034-7

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Italy: Gene-edited rice to protect against blast disease

Italy to launch first field test of a gene-edited crop, rice engineered to protect against disease without the use of agrochemicals

Rosanna Magnano | 24 Ore | April 8, 2024

Rice blast fungus or ‘brusone’. Credit: International Rice Research Institute via CC-BY-NC-SA-2.0

The witch hunt against old GMOs will soon be a distant memory (perhaps). And after more than twenty years of blocks, a new generation of biotech (but not transgenic) plants will take its first steps in Italy. With the last and definitive green light from the Ministry of the Environment, experimental sowing of a variety of rice in the open field was obtained thanks to the new genomic techniques, known in Italy as TEA, assisted evolution techniques.

It is a rice capable of resisting, without the use of fungicides, the attacks of the Pyricularia oryzae fungus which causes the disease commonly known as “brusone” [in Italian, or rice blast fungus in English], the most serious fungal pathology of rice which in some years can lead to production losses even of the 50%. The request for authorization for the tests was presented by the University of Milan, where the first research group in the country coordinated by the biotechnologist Vittoria Brambilla, [thanks to updated] rules for field trials of plants developed with genome editing or cisgenesis.

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Laboratory tests using resistance tests have given excellent results in terms of productivity and without the administration of agrochemicals.

[Editor’s note: This article has been translated from Italian and edited for clarity.]

This is an excerpt. Read the original post here

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New Zealand: Management of diseases impacting Solanaceae horti

NZ: New partnership to collaborate to manage diseases impacting Solanaceae horti

Last week, the NZPPI Board agreed to sign the Solanaceae Readiness Operational Agreement (OA) on behalf of their Members. This agreement is a partnership between NZPPI, Vegetables NZ, Tomatoes NZ & Potatoes NZ to collaborate on projects to manage a range of diseases that have impacted Solanaceae horticulture crops in recent years.

The horticulture sectors have responded to several incursions in the past few years, including Pepino mosaic virus (PepMV) and Potato spindle tuber viroid (PSTVd), with an increasing risk of further incursions that will result in considerable costs and crop losses.

There are no confirmed projects or funding commitments in place at this stage, but discussions are underway to develop systems to avoid and manage future incursions. Plant producers play a key role in the production process and in managing these risks.

Signing the OA enables NZPPI to participate in the development of future management programmes, giving our members a say in how they are designed and implemented.

For more information:
New Zealand Plant Producers Incorporated
nzppi.co.nzPublication date: Mon 8 Apr 2024

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Jamaica: Lethal yellowing of coconut palm

Saturday, 09 March 2024 10:37:00

Grahame Jackson posted a new submission ‘LETHAL YELLOWING, COCONUT PALM – JAMAICA’

Submission

LETHAL YELLOWING, COCONUT PALM – JAMAICA

ProMED
http://www.promedmail.org

Source: Jamaica Observer [summ. Mod.DHA, edited]
https://www.jamaicaobserver.com/2024/03/05/spread-lethal-yellowing-disease-reduced-70/

Through the work of the Coconut Industry Board (CIB), Jamaica has been able to reduce the spread of the lethal yellowing disease in the coconut industry by 70%. CIB have contributed significantly through research which has allowed the development of varieties and hybrids with optimum resistance/tolerance to lethal yellowing. In addition, increased yields are obtained from these locally developed varieties that are adapting better to the climatic conditions.

Within the region, the disease was first discovered in the Cayman Islands in 1834 and was found in Jamaica in 1884. It became a real threat to Jamaica after 1961 and became even more significant in the 1970s when some 10 million trees of the ‘Jamaican Tall’ variety were destroyed. Lethal yellowing has caused severe economic losses in Jamaica.
—
Communicated by:
ProMED

[Lethal yellowing (LY) diseases of coconut and other palms are caused by phytoplasmas of the palm lethal yellowing (16SrIV; _Candidatus_ Phytoplasma palmae strains) group. A number of LY strains have been described from the Caribbean, Latin America, Africa and southern Asia. LY has seriously jeopardised coconut industries in the respective areas. LY-type diseases like Cape St Paul wilt (CSPW) in Ghana, the “maladie de Kaincope” in Togo and Awka disease (lethal decline, LD) in Nigeria, previously included in the 16SrIV group, have been reclassified as the new group 16SrXXII (Nigerian coconut lethal decline group, _Ca._ P. palmicola strains; see link below).

Symptoms include premature nut drop, blackening of inflorescences, yellowing of fronds; death of the palm usually occurs within 4 to 6 months. The planthopper _Myndus crudus_ is suspected to be the vector in the Americas, but different vectors may be involved in the spread of LY strains elsewhere. Seed transmission of the pathogens cannot be excluded; some weed species may serve as pathogen reservoirs. Jumps of LY across apparently unaffected coconut populations have been observed, possibly due to aerial spread of infectious vector insects or human activities. Even with strict controls, including certification of nuts and their parent trees, excluding infectious vector insects requires large quarantine efforts.

While LY affects many palm species, at least for coconut palm susceptibility may vary between cultivars or even within cultivars, depending on the region where they grow. Symptoms can be suppressed by tetracycline treatments, usually applied as trunk injections. The antibiotic inhibits multiplication of the pathogens but does not eliminate them. Therefore, treatments need to be repeated regularly. Commercial control of the diseases mostly relies on phytosanitation followed by replanting with resistant varieties.

An unexplained resistance breakdown of some widely used hybrids occurred earlier in Jamaica (ProMED post 20070522.1643) and caused great concern.

Pictures
LY symptoms on coconut and other palms:
https://www.growables.org/information/TropicalFruit/images/LethalYellowingFoliarSymptoms.jpg,
https://bugwoodcloud.org/images/768×512/1504008.jpg,
https://guyanachronicle.com/wp-content/uploads/2017/04/Lethal-Yellowing.jpg (leaf) and
http://www.cphdforum.org/wp-content/uploads/2015/06/LethalYellowingCoconutSymptom.jpg (fruit)
_Myndus crudus_:
https://bugwoodcloud.org/images/768×512/0725079.jpg

Links
Story also at:
https://jis.gov.jm/spread-of-lethal-yellowing-disease-reduced-by-70/ and
https://jamaica-gleaner.com/article/news/20240304/spread-lethal-yellowing-disease-coconut-industry-reduced-70
Lethal yellowing information:
https://doi.org/10.1079/cabicompendium.38647,
https://doi.org/10.3389/fpls.2016.01521,
https://doi.org/10.1111/j.1744-7348.2011.00480.x,
https://www.cphdforum.org/index.php/2015/06/03/about-lethal-yellowing-of-coconut/,
http://edis.ifas.ufl.edu/pp146 and
https://www.apsnet.org/edcenter/disandpath/prokaryote/pdlessons/Pages/LethalYellowing.aspx
16SrIV LY phytoplasma group taxonomy and species list:
https://www.uniprot.org/taxonomy/85624
16SrXXII classification of some LY-type diseases:
https://doi.org/10.1099/ijs.0.65000-0
16SrXXII LDN phytoplasma group taxonomy:
https://www.uniprot.org/taxonomy/590462
Phytoplasma resource centre:
https://plantpathology.ba.ars.usda.gov/phytoplasma.html
Information on LY vectors via:
https://bugguide.net/node/view/63
– Mod.DHA

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The genetic composition of fungi and its role in plant health

Exploring the genetic composition of fungi and its role in plant health

by University of Ottawa

Population analyses of R. irregularis. Credit: Nature Microbiology (2023). DOI: 10.1038/s41564-023-01495-8

The complex and very diverse world of fungi is often referred to as the fifth kingdom of organisms. It includes various yeasts, molds, and mushrooms. A team of scientists from the University of Ottawa (uOttawa) has uncovered the genetic secrets of a mysterious fungus, revealing the presence of two distinct nuclear populations within them, each playing distinct roles in how they interact with plants.

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Arbuscular mycorrhizal fungi (AMF) are tiny fungi that live in harmony with plants, sharing their genetic diversity and creating a vibrant atmosphere in plant roots and with below-ground microbes. Scientists have been studying AMF for years but are still puzzled by it. Its bodies are like bags packed with thousands of nuclei cells, and how these fungi cooperate with plants has long been unclear.

“There were numerous unresolved questions regarding AMF, mainly because these fungi are always multinucleated and do not exhibit observable sexual characteristics,” says Professor Nicolas Corradi, who holds the Chair in Microbial Genomics at the Department of Biology, University of Ottawa. “It has been proposed that AMF possess unique genetics and have undergone an unconventional evolution.”

Professor Corradi and colleagues investigated the asexual reproduction of AMF, specifically Rhizophagus irregularis. In 2016, they discovered strains that showed signs of sexual reproduction, with two populations of nuclei co-existing in large cells. “We found that strains having two populations (AMF heterokaryons) are more resilient and could access plant roots more easily, an indication they could be better bio-stimulants.”

However, without their complete genome, the researchers could not know why these strains are more successful plant symbionts.

Phylogenetic tree constructed with 65 R. irregularis strains. Haplotypes from AMF heterokaryons are shown in yellow squares. Based on relative branch lengths, the phylogeny resolves at least nine clades, which are highlighted in color. The tree was made using IQTREE algorithm, in GTR-FO mode with 1,000 bootstrap replicates. Scale bar represents 0.05 substitutions per site. When available, the MAT type of the strain is shown in parentheses. Note: the G1 strain located in clade VI noted with an asterisk is homokaryotic and does not represent the heterokaryotic isolate G1 (DAOM-970895) from clade IV. Credit: Nature Microbiology (2023). DOI: 10.1038/s41564-023-01495-8

To address this, Professor Corradi and his team employed advanced sequencing techniques, including RNA sequencing and third-generation DNA sequencing, to analyze differences in structure, content, and expression between the co-existing genomes.

“AMF heterokaryons have two haplotypes that physically separate among a large number, possibly millions, of co-existing nuclei. This phenomenon is unprecedented in any other organism,” explains Professor Corradi.

Their analyses also demonstrated that the two populations act very differently depending on their surrounding environment and their plant host. “Not only did we find that the two populations differ dramatically in the genes they harbor, but also that these are differently expressed and change in abundance depending on which plant they interact with,” adds Professor Corradi.

The symbiotic interactions between AMF and host plants are crucial for nutrient exchange, pathogen protection, and ecosystem sustainability. Studying these interactions will help improve agricultural practices by producing tailored biostimulants, enhancing plant growth, and promoting ecosystem health.

The study, titled “Arbuscular mycorrhizal fungi heterokaryons have two nuclear populations with distinct roles in host–plant interactions,” was published in Nature Microbiology.

More information: Jana Sperschneider et al, Arbuscular mycorrhizal fungi heterokaryons have two nuclear populations with distinct roles in host–plant interactions, Nature Microbiology (2023). DOI: 10.1038/s41564-023-01495-8

Journal information: Nature Microbiology 

Provided by University of Ottawa 

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In symbiosis: Plants control the genetics of microbes

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Horizontal gene transfer: How fungi improve their ability to infect insects

by Eva Sittig, Kiel University

The research team investigated genetic changes of Metarhizium fungi during infection of the invasive Argentine ant, shown here are its workers, on the right with brood. Credit: Sina Metzler & Roland Ferrigato, ISTA

Researchers at the Kiel Evolution Center have investigated for the first time in detail how a fungus important for biological plant protection can pass on an advantageous chromosome horizontally, using a previously little-studied way of exchanging genetic information.

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Sustainable plant protection measures that are not based on chemical pesticides rely on various organisms and biological agents to protect crops from pests. Such organisms used for biological plant protection are, for example, microscopic fungi of the genus Metarhizium, which can attack and kill a variety of plant-pathogenic insects and are used, for example, in South American sugar cane cultivation.

The molecular mechanisms of fungal infection and the immune response of insects are in an ongoing process of mutual evolutionary adaptation. In a joint project with colleagues from the Institute of Science and Technology Austria (ISTA), a research team from Kiel University investigated the genetic changes in the fungus during infection of the invasive Argentine ant (Linepithema humile).

The researchers examined the genomes of different strains of the fungi Metarhizium robertsii and Metarhizium brunneum from an earlier co-infection experiment in which ants had been infected with the fungus mix.

In the study, the outgrowing spores were used to infect new ants over 10 consecutive infection cycles. When analyzing the fungal genomes from these infection series, the fungal geneticist and first author of the study, Dr. Michael Habig from Kiel University, made an exciting observation: his analyses showed that a single chromosome was very frequently exchanged horizontally between two different strains.

This chromosome contains certain genes that the scientists suspect may give the fungus an advantage in infecting its hosts. The horizontal transfer of entire chromosomes has rarely been described scientifically and has now been studied in detail for the first time. The researchers from the Kiel Evolution Center (KEC) and ISTA published their results in the journal Proceedings of the National Academy of Sciences.

Horizontal chromosome transfer detected in insect-damaging fungus

Scientists use the term horizontal gene transfer to describe how living organisms can transfer genetic material between different individuals, including those of other species. In this way, bacteria exchange extensive genetic information, often in the form of plasmids, in order to quickly adapt to changing environmental conditions or to adapt to the host. The rapid evolution of various pathogens is based on such mechanisms, among other things.

“In fungi and many other so-called eukaryotic organisms, however, horizontal gene transfer in the form of entire chromosomes is very rare and has hardly been researched to date,” says Dr. Michael Habig, research associate at Kiel University.

“The analysis of the genetic information of the fungal strains shows that M. robertsii independently transferred a single chromosome a total of five times during the co-infection experiments, but no other genetic information from one strain to another via horizontal transfer,” continued Habig.

Further analyses also indicated that the same chromosome can also be found in the distantly related, also insect-damaging fungus species Metarhizium guizhouense, whose common evolutionary origin with M. robertsii dates back around 15 million years.

“The chromosome in M. guizhouense is significantly less altered than would be assumed for the long period of separate evolution of the two fungal species. The chromosome therefore also appears to have been passed on naturally between these different fungal species—and probably horizontally,” says Habig.

Analysis of the chromosome indicates possible survival advantages for the fungus

The chromosome examined is a so-called accessory chromosome. This means that it does not occur in all individuals of a species and contains non-essential genetic information.

“The experiments showed that, under certain conditions, the fungus that had received the accessory chromosome had competitive advantages over fungi of the same strain that had not received the chromosome and were able to prevail against them. We want to investigate the details of these advantages in more detail in the future,” says Habig.

The Kiel research team has already been able to derive initial indications from the analysis of the genes on the chromosome. “The chromosome contains hundreds of genes whose potential functions we will only be able to decipher in the future. However, we have already been able to identify 13 candidate genes that could presumably be responsible for so-called effector proteins, which can interact with the insects’ immune system, for example,” Habig continues.

The transfer of the chromosome may therefore have advantages for the fungus, the functional basis of which is still unclear. However, one plausible possibility is the transfer of certain genes that produce chitin-cleaving enzymes and can thus improve the ability to infect the insects.

“It is remarkable that we have found the genes of three such enzymes, among others, which presumably play a role in the degradation of the chitin-containing cuticle of the host insect. This could influence a crucial step in the infection process, as the fungal spores are dependent on penetrating the protective exoskeleton of the host in order to infect it,” says Professor Sylvia Cremer, last author of the study, from the Institute of Science and Technology Austria (ISTA).

Overall, the research work offers interesting new aspects on a way of exchanging genetic information that has been little studied in fungi to date.

“Our new work shows that horizontal chromosome transfer occurs regularly in fungi and that this mechanism can confer advantages to the recipient strain, at least in experiments under certain conditions,” says Habig.

The Kiel research team and its collaboration partners from ISTA thus describe in detail for the first time a new aspect in the genome evolution of fungi, which may be able to use bacteria-like mechanisms of rapid evolutionary adaptation, for example to increase their virulence or harmfulness to their host organism and to transfer genetic information across species boundaries.

In the future, the researchers want to use the example of M. robertsii to investigate the relationships between horizontal chromosome transfer, possible fitness advantages and the mutual adaptation of fungi and insects in detail and thus gain further insights into this organism, which is important for plant protection.

More information: Michael Habig et al, Frequent horizontal chromosome transfer between asexual fungal insect pathogens, Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2316284121

Journal information: Proceedings of the National Academy of Sciences 

Provided by Kiel University 

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Examining the promotion of Arabidopsis immune responses by a rhizosphere fungus

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Ghana: Cacao sustainability: The case of cacao swollen-shoot virus co-infection’

Saturday, 09 March 2024 10:24:18

PestNet

Grahame Jackson posted a new submission ‘Cacao sustainability: The case of cacao swollen-shoot virus co-infection’

Cacao sustainability: The case of cacao swollen-shoot virus co-infection

PLOS

• Folashade B. Agusto ,
• Maria C. A. Leite,
• Frank Owusu-Ansah,
• Owusu Domfeh,
• Natali Hritonenko,
• Benito Chen-Charpentier

Abstract

The cacao swollen shoot virus disease (CSSVD) is among the most economically damaging diseases of cacao trees and accounts for almost 15–50% of harvest losses in Ghana. This virus is transmitted by several species of mealybugs (Pseudococcidae, Homoptera) when they feed on cacao plants. One of the mitigation strategies for CSSVD investigated at the Cocoa Research Institute of Ghana (CRIG) is the use of mild-strain cross-protection of cacao trees against the effects of severe strains. In this study, simple deterministic, delay, and stochastic ordinary differential equation-based models to describe the dynamic of the disease and spread of the virus are suggested. Model parameters are estimated using detailed empirical data from CRIG. The modeling outcomes demonstrate a remarkable resemblance between real and simulated dynamics. We have found that models with delay approximate the data better and this agrees with the knowledge that CSSVD epidemics develop slowly. Also, since there are large variations in the data, stochastic models lead to better results. We show that these models can be used to gain useful informative insights about the nature of disease spread.

Read on: https://doi.org/10.1371/journal.pone.0294579

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Early detection and tracking of ToBRFV virus entry point

“It is important to be prepared and to understand the virus infection in order to effectively mitigate its spread or prevent a potential epidemic,” explains Harmen Hummelen, production quality manager at Bayer.

The tomato brown rough fruit virus (ToBRFV) is becoming increasingly widespread. In the event of infection, it is important to be prepared, understand the viral infection, and manage its spread.

A ToBRFV infection that is not properly managed can have a significant impact on plant quality and yield. Detecting the virus early after infection is essential, and this article presents some tips and suggestions for early detection.

Recognition in the greenhouse
Recognizing an early infection is not easy, partly because most people have never seen the disease before. There are some general guidelines to help with early detection and recognition of the ToBRFV virus, and an experienced person who can “read” plants is one of the most valuable helpers.

Such a person is more likely to detect any “anomaly” for a particular variety or time of year (for example, plants with a slightly different color or shape). These symptoms may not be directly linked to the ToBRFV virus, as they can often resemble fertilizer deficiency or other stress factors.

For example, one of the symptoms may be that the plant is a little shorter for no clear reason. These plants, or their neighbors, may have fruits that do not ripen normally. Some fruits, particularly at the top of a cluster, ripen later, or ripening is more uneven, perhaps with a few more spots. The top of the plant could also turn a little paler green. These are all symptoms that can be caused by many factors, but they can also indicate the presence of ToBRFV.

The problem is that, in some cases, the virus causes no symptoms on the plant and only manifests itself on the fruit. This seems to occur especially in older crops, where virtually no symptoms are observed, but the virus is present. This increases the risk of a missed infection spreading to the next crop cycle.

It is therefore very important to carry out another, more thorough check. The final step in determining whether ToBRFV is present is to carry out a test.

 Tomato brown rugose fruit virus | Cornell Vegetables: Tomato brown rugose fruit virus | Cornell Vegetables

“A simple and effective method of testing for the presence of ToBRFV is to take a sample from the calyx of the fruit,” explains Leonie Hogendonk, De Ruiter development manager.

Test
A laboratory or rapid test may indicate the presence of infection. In both cases, care should be taken to collect several parts of the plant, such as the calyx and actively growing shoots, in a single sample, as the virus may not be present in all parts of the plant. If the first sample does not confirm the visual diagnosis, feel free to produce another sample from a second plant or combine several plants into a single sample.

Diagnosis of drainage water is also a good way of detecting infection at an early stage. Belgian growers have analyzed this water in the laboratory, and, in some cases, a viral infection can be detected up to 10 weeks before the appearance of visual symptoms.

Caution is key when testing early in the season after a previous infection, as it is possible that RNA from the previous season’s dead virus may be detected. However, if the amount of virus increases, it is clear that it is a live virus developing in the plants.

Virus detection should be limited to a certain block or section of the greenhouse, and such early detection allows further action to be taken, thus reducing the spread of the virus within the greenhouse or nursery.

 Figure 1. The virus is not uniformly distributed throughout the plant. A virus penetrates somewhere in the plant and then moves with the phloem towards the roots. Almost at the same time, it also moves to the upper, young, and growing part of the plant, and it can take some time for the rest of the plant to become infected.

Entry point of the virus in the greenhouse
When the first plants are detected, the next question is why the infection has occurred there. In practice, it is not always possible to answer this question. The virus is invisible, and even with good prevention and hygiene measures, low levels of the virus can be introduced at any given time. The location of the virus is not necessarily the entry point.

The virus can enter via people, equipment, or animals. It is not yet known how long it takes for the virus to infect the crop from the vector (what carries the virus), and this can range from 10 minutes to a day or more. This means that the virus can appear for the first time in the middle of the greenhouse, even if it has been introduced elsewhere. The virus also needs a plant that is sufficiently sensitive to allow infection.

All these unknown factors make it difficult to trace the initial point of entry. It is therefore important to maintain high levels of hygiene in greenhouses and crops from the outset and throughout the growing season.

Set-back from infection date
In some experiments, virus symptoms appear in young plants after only 10 days. However, in older plants, no clear symptoms may be observed for months, sometimes even until the end of cultivation. Finding that first plant is a major challenge. It is very likely that the first infected plant is one of the neighboring plants and, by the time the symptoms are discovered, the infection may involve 10 to 20 plants in total.

Good screening to find the virus as early as possible and good hygiene to reduce the spread of the virus is essential to keep as many plants healthy as possible until the end of the growing cycle.

For more information: vegetables.bayer.com/frPublication date: Tue 9 Apr 20

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Ghana: World Bank loan to rehabilitate plantations destroyed by the cocoa swollen shoot virus

Ghana to expand cocoa rehabilitation with $200m World Bank loan

 20th Feb 2024    |     Source: Graphic Online

Ghana Cocoa

Ghana’s COCOBOD will use part of a $200 million World Bank loan to rehabilitate plantations destroyed by the cocoa swollen shoot virus, which causes drops in yields and kills trees, the regulator’s deputy Chief Executive in charge of operations said on Thursday, February 15, 2024.

 The disease has wiped off about 500,000 hectares of farmlands and reduced cocoa output from the West African nation, the world’s second biggest cocoa producer after neighbour Ivory Coast.

Ghana’s output declined to 600,000 metric tons last year after peaking at 1.048 million tons in the 2020/21 season, as the cocoa swollen shoot virus, aging plantations, illegal mining and smuggling took a toll on the sector.

A total of $132.8 million of the loan secured by the government last year and the counterpart funding will finance Cocobod’s rehabilitation of farms and help to enhance knowledge on the virus strains, a project information document showed.

“The rehabilitation will take a minimum of five years to start getting economic production,” Cocobod’s Emmanuel Opoku told Reuters, adding that efforts had been hampered by the country’s economic crisis and the board’s limited funds.

The board will take over disease-infested farms, cut and replace sick cocoa trees, aiding growth to a fruiting stage before handing them back to farmers.

In 2018, Cocobod used part of a $600 million Africa Development Bank (AfDB) loan to rehabilitate aging plantations and those affected by the disease.

But the programme, originally meant to cover 156,000 hectares of plantations, was caught up in Ghana’s worst economic crisis in a generation during which inflation spiralled and the cedi currency depreciated sharply, Opoku said.

He said the AfDB facility benefited more than 88,000 hectares of farmlands, of which 40,000 hectares were ready to be given back to farmers in “the coming days”.

Alhassan Bukari, president of the country’s Cocoa, Coffee and Sheanut Farmers’ Association, told Reuters that rehabilitation efforts needed to be aggressive as many farmers were affected.

Ghana’s graded and sealed cocoa arrivals fell by 35% between the start of this season on Sept. 1 and Jan. 31 this year due to the intensity of the seasonal dry Harmattan wind and what Cocobod described as production.

–

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Nigeria: GM potatoes to be released

AFRICA, BREEDING, GMO, NEWS MARCH 2024, ORGANIZATIONS IN THE NEWS, VARIETIES

GM potatoes to be released to Nigerian farmers in 2025

on March 21, 2024

New potato varieties modified to withstand the deadly late blight disease said to be responsible for over 90 percent destruction on farmers’ fields in Nigeria will be available to farmers from the 2025 planting season, Dr Charles Amadi, a breeder with the National Root Crop Research Institute (NRCRI), said.

According to a news story published on EnviroNews Nigeria, Dr Amadi is the Principal Investigator, Global Biotechnology Potato Partnership (GBPP) project in Nigeria under the USAID-funded Feed the Future Project that is implemented in four countries – Kenya, Bangladesh, Indonesia and Nigeria.

The Partnership is coordinated by Michigan State University and involves various partners including the National Root Crop Research Institute, Umudike; the African Agricultural Technology Foundation (AATF); and International Potato Centre (CIP).

Dr Amadi said: “After two years of research work in confinement and multilocation in potato growing belts of Nigeria, because of the uniform results from all locations, we are confident that threats of late blight would be successfully contained in Nigeria with the release of these late blight resistant varieties that will be available in 2025.

“We just need one more year of regulatory multilocation data to present them to National Biosafety Management Agency for environmental release. If we get the permit for environmental release this year, we will take them to On-farm trials in 2025.

Source: EnviroNews Nigeria. Read the full story here
Cover image: Credit EnviroNews Nigeria

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Australia: World’s first GM banana approved

World’s first GM banana approved in Australia

It’s genetically modified to resist a devastating fungal infection.

Queensland University of Technology

By Kristin Houser

March 11, 2024

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AGRICULTURE

GENETICS

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Australia has just approved a banana that has been genetically modified to resist the fungal infection known as Panama Disease — a devastating threat to banana crops around the world. 

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It is the first GM banana ever approved, but varieties designed to resist other crop diseases are already in the works.

Money in the banana stand: Bananas are big business. As of 2023, the industry was valued at $25 billion, and many people around the world depend on the fruit for income or nutrition. 

At any moment, though, a country’s banana industry can be crippled by an invasion of Panama Disease TR4 — an incurable, practically ineradicable infection. 

“[The fungus] stays in the ground for more than 50 years, wiping out banana crops and destroying farms for generations.”JAMES DALE

TR4 has been spreading globally for decades and attacks nearly all banana varieties, including the Cavendish banana, the world’s most popular variety since a previous epidemic of Panama Disease wiped out the Gros Michel banana in the 1950s. 

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“The devastating Panama Disease TR4 is caused by a soil-borne fungus that stays in the ground for more than 50 years, wiping out banana crops and destroying farms for generations,” said James Dale, director of the Centre for Tropical Crops and Biocommodities at Australia’s Queensland University of Technology (QUT). “It is a huge problem.”

Two decades to save the banana: Dale and his colleagues have spent more than 20 years developing the QCAV-4 banana, a genetically modified (GM) variety of the Cavendish banana that is highly resistant to Panama Disease TR4.

All that hard work has now paid off, as Australian regulators recently ruled that the GM banana is as safe and nutritious as unmodified bananas. If the nation’s food ministers don’t question the ruling by mid-April, the banana will be approved for sale in Australia.

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“This is a wonderful example of fundamental research progressing through a commercialisation journey into a tangible outcome … it’s fantastic to reach this milestone,” said Margaret Sheil, QUT’s Vice-Chancellor Professor. 

How it works: QCAV-4 isn’t the first gene-edited banana to be approved for human consumption — in 2023, the Philippines greenlit a variety of banana that was edited to not turn brown so quickly. 

That was done by simply silencing a gene the banana already had, though. The QUT team created its GM banana by splicing in a gene called “RGA2” that comes from a wild banana variety. This gene makes those bananas nearly immune to Panama Disease, and while Cavendish bananas have the same gene, their version is dormant.

“There’s nothing scary,” Dale told ABC News. “The gene was already present in Cavendish … It just doesn’t work, so we have put in a version that works.”

“This is really our safety net.”JAMES DALE

Looking ahead: If the GM banana is approved for sale in Australia, that doesn’t mean anyone is going to start growing and selling it — the QUT team views QCAV-4 as a back-up plan, something that could be produced if Panama Disease started spreading across Aussie banana farms.

“[T]his is really our safety net,” said Dale. “Cavendish bananas are not going to disappear [but] this banana is ready to go, though, if TR4 really gets going and starts to really hurt our industry.”

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