How Viruses Attack Plants

Viruses are incapable of reproducing without the help of a host, whose cells copy their genetic material and fabricate the building blocks of new virus particles.

By Claire Asher | February 1, 2018

Most plant viruses are transmitted by insect vectors that cause damage to the plant and create an entry point for pathogens, or that tap into the phloem to feed. Once inside, viruses use the handful of genes in their tiny genomes to orchestrate the plant cells’ machinery, while evading the plant’s defenses. Below is a generalized depiction of this infection process for RNA viruses, the most common type of plant virus.

© PENS AND BEETLES STUDIOS

1. Some viruses can infect plants when aphids and other insects tap into the phloem to feed. Such insect vectors can also pick up virus particles and carry them to new plant hosts.
2. Other viruses infect plant cells through a wound site created by a leaf-munching insect such as a beetle.

© PENS AND BEETLES STUDIOS

1. Viral capsid shell opens to release the viral genome, which is translated into proteins that direct the formation of a viral factory from membranes of the endoplasmic reticulum and other organelles.
2. Antiviral proteins, such as those in the Argonaute family, patrol cells for invading pathogens, but they cannot break into the viral factories.
3. Viral RNA is replicated and exported to the cytoplasm.
4. Viral RNA and newly assembled viral particles move to other cells through plasmodesmata, which can be widened by virus-encoded movement proteins.
5. Some virus particles enter the plant’s transport streams.

------------------

This article infographic on virus attack on plants is also relevant to turf grasses.  There are quite a few virus diseases of relevance to turf, and this article offers some information on what happens with a generic infection, although some other pathways are also possible.

The article was first published in the online edition of The Scientist, late February 2018.

See - https://www.the-scientist.com/?articles.view/articleNo/51433/title/How-Viruses-Attack-Plants/&articles.view/articleNo/51433/title/How-Viruses-Attack-Plants&utm_campaign=TS_DAILY%20NEWSLETTER_2018&utm_source=hs_email&utm_medium=email&utm_content=60971361&_hsenc=p2ANqtz-8sRnFpf4PSVKhS4qCRqjpdE3cVxZ1X-9R7OqOnFcESv0ja5HFtMrFtLS0dq84GAgWhL76mls4oPJVH6tAS1ENFvd0ibsCrEhHoAA3AZacEjPsaOEY&_hsmi=60971361

Insects to Eat Styrofoam - Waste Problem Solved?

Could biology solve the problem of disposing of plastic waste?

It might just be the case according to a recent study at Stanford University.

Reporting is here -http://www.nbcnews.com/tech/innovation/styrofoam-eating-mealworms-could-happily-dispose-plastic-waste-n435901   along with some photos.

But in essence the larvae of mealworms can be raised on styrofoam!  Yes, styrofoam.

The world uses a lot of styrofoam each year with a large amount in simple, single use styrofoam cups for coffee and similar take away drinks.

I have personally observed the good old cockroach tuck into styofoam.........but this technology of raising insects on styrofoam seems such a simple option that would lend itself to mass production.

I just wonder though, at the real will to set something up.

Is Biosecurity Adequate in Northern Australia?

There is a lot of  future for north Australia that is dependent on effective biosecurity in the region.

Over the past several years the litany of biosecurity breaches seems to be significant :

• Panama disease in a major production area of bananas in north Queensland - Tropical Race 4 [ TR4] a highly pathogenic variant
• known areas of the same disease around Darwin, and banning bananas being grown in some NT areas, and restrictions on banana plant movements
• a major effort at eradication of Banana Freckle disease near Darwin  after the exotic disease was found in the NT
• Cucumber Green Mottle Mosaic Virus in curcurbits, especially melons, in the NT in 2014 and adjacent states also potentially infected, but not all jurisdictions are looking yet
• an Asian Bee colony discovered in Darwin in the last few days, after hitching a ride on a caravan, but with an absent queen - who is suspected of absconding with a new colony and may be setting up locally [ if that establishes then there will be mayhem]

Asian honey bees

• culicoides driven diseases also seem to be increasing - with blue tongue arriving many years ago from wind borne insects, and more recently a few more cases of chikungunya around the north [ at least so far the mosquito involved in spread does not seem to be around]; dengue outbreaks in some locations in north Queensland [ although the Australian derived disease in mosquities - Wolbachia may be a great agent to make a difference] if needed, as well as considerable issues surrounding other mosquito diseases such as Ross River Fever and variants as well as Murray Valley Encephalitis.  

We would like to see more agricultural development in the north of Australia, but biosecurity does need to be remembered......and emphasised.

While there has been money marked to be used for improved biosecurity in the north the track record is not all that encouraging.  And one must not forget human diseases either.

A meeting this week included a presentation on the dollars to be allocated to biosecurity improvements, R and D, upgraded awareness etc.  And presented by someone from outside the north Australia area seemed to leave local north Australia scientists and producers rather underwhelmed.  Some stated that industry  - a very diverse one at that - is not being adequately consulted or even advised.  One thinks of plant based industries - but often just the major ones of temperate Australia, but seems to forget fish farms, prawn farms, crocodiles and other non mainstream animal industries let alone the plant and animal based industries that thrive in the north - nurseries, asian vegetables, sugar, chia, cattle, pastures etc.  Are they being assessed adequately for biosecurity threats?

http://www.agricultureminister.gov.au/pages/media-releases/agwp-biosecurity.aspx

http://www.agricultureminister.gov.au/pages/media-releases/12-4-million-for-indigenous-rangers.aspx


These are recent media release on new measures in biosecurity for north Australia, but there is little detail.  Finding any information on detail is also VERY difficult, as it seems to be hidden away from easy access.

Biosecurity might not be very sexy in terms of rural development - but it is important, and needs greater highlighting of what is being planned.

Biosecurity - Fruit Flies - Taxonomy Improves- Species Combined

Media release: What’s in a name? Everything - if you’re a fruit fly

29 October, 2014

A global research effort has finally resolved a major biosecurity issue: four of the world’s most destructive agricultural pests are actually one and the same.

For twenty years some of the world’s most damaging pest fruit flies have been almost impossible to distinguish from each other. The ability to identify pests is central to quarantine, trade, pest management and basic research.

In 2009 a coordinated research effort got underway to definitively answer this question by resolving the differences, if any, between five of the most destructive fruit flies: the Oriental fruit fly, the Philippine fruit fly, the Invasive fruit fly, the Carambola fruit fly, and the Asian Papaya fruit fly. These species cause incalculable damage to horticultural industries and food security across Asia, Africa, the Pacific and parts of South America.

The Philippine fruit fly was formally recognised as the same species as the Asian Papaya fruit fly in 2013. The latest study goes further, conclusively demonstrating that they are also the same biological species as the Oriental and Invasive fruit flies. 

These four species have now been combined under the single name: Bactrocera dorsalis, the Oriental fruit fly. The closely-related Carambola fruit fly remains distinct.

Professor Tony Clarke, Chair of Fruit Fly Biology and Management from the Plant Biosecurity Cooperative Research Centre (PBCRC) and the Queensland University of Technology (QUT), believes the integrated multidisciplinary nature of the project leaves little doubt the species are identical.

“More than 40 researchers from 20 countries examined evidence across a range of disciplines, using morphological, molecular, cytogenetic, behavioural and chemoecological data to present a compelling case for this taxonomic change,” he said. “This outcome has major implications for global plant biosecurity, especially for developing countries in Africa and Asia,” said Professor Clarke. “For example, Invasive (now Oriental) fruit fly has devastated African fruit production with crop losses exceeding 80 per cent, widespread trade restrictions with refusal of shipments into Europe and Japan, and significant economic and social impacts to farming communities.”

Keeping exotic fruit fly out is a major concern for Australian biosecurity agencies. While an outbreak of Papaya fruit fly near Cairns in the mid-1990s inflicted $A100 million in eradication and industry costs, current estimates rate the Oriental fruit fly as the biggest threat to Australian plant biosecurity, with the total cost to the nation of an invasion estimated at $A1 billion. 

Combining the four species will mean a major reassessment of Australia’s exotic fruit fly risk.

“Globally, accepting these four pests as a single species will lead to improved international cooperation in pest management, more effective quarantine measures, reduced barriers to international trade, the wider application of established post-harvest treatments, improved fundamental research and, most importantly, enhanced food security for some of the world’s poorest nations,” said Professor Clarke.

The paper, B. papayae, B. invadens, and B. dorsalis synonymy, is published today in the journal Systematic Entomology: http://onlinelibrary.wiley.com/doi/10.1111/syen.12113/abstract and is a collaboration between 33 research organisations in 20 countries, supported by the Food and Agriculture Organisation of the United Nations and the International Atomic Energy Agency.

More information and interviews: Tony Steeper, PBCRC Communications Manager, 0417 697 470, t.steeper@pbcrc.com.au