'Stealth bomber' fungus sneaks into crops: study

Major crop-killing mildews sneak into plants as "stealth bombers," disguising themselves to thwart plant defenses and cause mass destruction, said research published Thursday in the journal Science.

In a pair of studies, researchers describe how they mapped the genomes of two of the plant-destroyers and detail how the diseases shed giveaway genes that could trigger an immune attack in the plants they invade.

Powdery mildew plagues seem to arise from nowhere and can devastate barley, corn, grapes, potatoes and more, causing huge food losses worldwide particularly in cool, wet climates in North America, Europe and Asia.

Every year, 20 to 40 percent of the world's harvest is lost because of pests, and the new knowledge could help design tougher plants and more potent fungicides to halt their deadly creep.

The diseases - Blumeria graminis (or barley disease) and Hyaloperonospora arabidopsidis (a flowery, mustard-related plant considered a model for biology research) - start with tiny parasites that cause dusty white spots on plant leaves and stems.

Farmers have tried to ward off such diseases by rotating crops and treating fields with fungicides, but often the plagues spread too quickly.

Now scientists know why. The organisms are able to disguise themselves so that the plant does not recognize a threat, allowing the fungus to get inside where it can wreak havoc and spread to other plants.

Parasites inside the genome transform themselves, shedding genetic traits so that the plant is confused and does not attack them, explained the study on barley disease that was led by scientists at Imperial College London.

"The mildew is able to evolve so quickly because multiple parasites within the genome, known as 'transposons,' help it to disguise itself and go unrecognized by the plant's defenses," said lead author Pietro Spanu.

"It is as if the transposons confuse the host plant by changing the target molecules that the plant uses to detect the onset of disease."

Downy mildew, another name for the type of disease caused by H. arabidopsidis, is an oomycete, or a fungal-like organism that has evolved from marine algae.

"Hyaloperonospora arabidopsidis is one of the stealth bombers of the world of plant pathogens," said lead author Jim Beynon of Britain's University of Warwick.

"We can see much of how it has actually slimmed down some key elements of its genetic material in order to get around the plant's natural defenses - essentially by stealth."

The research team also included The Sainsbury Laboratory, and Virginia Polytechnic Institute and State University, also known as Virginia Tech.

John McDowell, an associate professor in Virginia Tech's Department of Plant Pathology, Physiology, and Weed Science, said that by comparing the newly sequenced genomes to other plant pathogens, scientists learned why the mildew is so potent.

"Many plant pathogens contain large families of related genes that serve as powerful weapons but can also trigger equally powerful immune responses in the plant," said John McDowell.

"Our comparisons across multiple genomes revealed that many of these gene families have been reduced in size or completely discarded in H. arabidopsidis.

"This evolution towards stealth helps explain why this mildew and its relatives are widely distributed and cause diseases on many important crops."

Scientists are looking for a genetic solution to the crop-destroyers by developing strains of plants that are resistant to pathogens and pests, now that they know more about the plants' immune systems.

"Such crops will reduce the need to spray pesticides and fungicides and they will give better yields, as less will be lost to disease," said Dale Sanders of the John Innes Centre, a British plant science research institute.

ksh/jkb

 

Life and Style
ebookNow available in paperback
ebooks
ebookPart of The Independent’s new eBook series The Great Composers
  • Get to the point
Latest stories from i100
Have you tried new the Independent Digital Edition apps?

ES Rentals

    Independent Dating
    and  

    By clicking 'Search' you
    are agreeing to our
    Terms of Use.

    iJobs Job Widget
    iJobs General

    Ashdown Group: Senior Accounts Assistant - Accounts Payable - St. Albans

    £26000 - £28000 per annum + benefits : Ashdown Group: Senior Accounts Assistan...

    Ashdown Group: Treasury Assistant - Accounts Assistant - London, Old Street

    £24000 - £26000 per annum + benefits : Ashdown Group: A highly successful, glo...

    Recruitment Genius: Installation and Service / Security Engineer

    £22000 - £40000 per annum: Recruitment Genius: This company is part of a Group...

    Recruitment Genius: Service Charge Accounts Assistant

    £16000 - £18000 per annum: Recruitment Genius: Are you a a young, dynamic pers...

    Day In a Page

    General Election 2015: Chuka Umunna on the benefits of immigration, humility – and his leader Ed Miliband

    Chuka Umunna: A virus of racism runs through Ukip

    The shadow business secretary on the benefits of immigration, humility – and his leader Ed Miliband
    Yemen crisis: This exotic war will soon become Europe's problem

    Yemen's exotic war will soon affect Europe

    Terrorism and boatloads of desperate migrants will be the outcome of the Saudi air campaign, says Patrick Cockburn
    Marginal Streets project aims to document voters in the run-up to the General Election

    Marginal Streets project documents voters

    Independent photographers Joseph Fox and Orlando Gili are uploading two portraits of constituents to their website for each day of the campaign
    Game of Thrones: Visit the real-life kingdom of Westeros to see where violent history ends and telly tourism begins

    The real-life kingdom of Westeros

    Is there something a little uncomfortable about Game of Thrones shooting in Northern Ireland?
    How to survive a social-media mauling, by the tough women of Twitter

    How to survive a Twitter mauling

    Mary Beard, Caroline Criado-Perez, Louise Mensch, Bunny La Roche and Courtney Barrasford reveal how to trounce the trolls
    Gallipoli centenary: At dawn, the young remember the young who perished in one of the First World War's bloodiest battles

    At dawn, the young remember the young

    A century ago, soldiers of the Empire – many no more than boys – spilt on to Gallipoli’s beaches. On this 100th Anzac Day, there are personal, poetic tributes to their sacrifice
    Dissent is slowly building against the billions spent on presidential campaigns – even among politicians themselves

    Follow the money as never before

    Dissent is slowly building against the billions spent on presidential campaigns – even among politicians themselves, reports Rupert Cornwell
    Samuel West interview: The actor and director on austerity, unionisation, and not mentioning his famous parents

    Samuel West interview

    The actor and director on austerity, unionisation, and not mentioning his famous parents
    General Election 2015: Imagine if the leading political parties were fashion labels

    Imagine if the leading political parties were fashion labels

    Fashion editor, Alexander Fury, on what the leaders' appearances tell us about them
    Phumzile Mlambo-Ngcuka: Home can be the unsafest place for women

    Phumzile Mlambo-Ngcuka: Home can be the unsafest place for women

    The architect of the HeForShe movement and head of UN Women on the world's failure to combat domestic violence
    Public relations as 'art'? Surely not

    Confessions of a former PR man

    The 'art' of public relations is being celebrated by the V&A museum, triggering some happy memories for DJ Taylor
    Bill Granger recipes: Our chef succumbs to his sugar cravings with super-luxurious sweet treats

    Bill Granger's luxurious sweet treats

    Our chef loves to stop for 30 minutes to catch up on the day's gossip, while nibbling on something sweet
    London Marathon 2015: Paula Radcliffe and the mother of all goodbyes

    The mother of all goodbyes

    Paula Radcliffe's farewell to the London Marathon will be a family affair
    Everton vs Manchester United: Steven Naismith demands 'better' if Toffees are to upset the odds against United

    Steven Naismith: 'We know we must do better'

    The Everton forward explains the reasons behind club's decline this season
    Arsenal vs Chelsea: Praise to Arsene Wenger for having the courage of his convictions

    Michael Calvin's Last Word

    Praise to Wenger for having the courage of his convictions