Tag: tomato

Attack of the killer tomato fungus driven by mobile weapons package

By Ed Yong | March 17, 2010 5:25 pm

In Robert Louis Stevenson’s classic story, Dr Henry Jekyll drinks a mysterious potion that transforms him from an upstanding citizen into the violent, murderous Edward Hyde. We might think that such an easy transformation would be confined to the pages of fiction, but a similar fate regularly befalls a common fungus called Fusarium oxysporum.

A team of scientists led by Li-Jun Ma and Charlotte van der Does have found that the fungus can swap four entire chromosomes form one individual to another. This package is the genetic equivalent of Stevenson’s potion. It has everything a humble, Jekyll-like fungus needs to transform from a version that coexists harmlessly with plants into a Hyde-like agent of disease. In this guise, it infects so many plant species so virulently that it has earned the nickname of Agent Green and has been considered for use as a biological weapon. It can even infect humans.

These disease-making chromosomes came to light after Ma and van der Does sequenced the genome of a variety of F.oxysporum called lycopersici (or ‘Fol’), which infects tomatoes. Its genome was unexpectedly massive, 44% bigger than its closest relative, the cereal-infecting F.verticillioides. Looking closer, Ma and van der Does found that most of this excess DNA lies within four extra chromosomes, which Fol has and its relative lacks. Together, they make up a quarter of Fol’s genome.

Ma and van der Does demonstrated the power of this extraneous quartet by incubating a harmless strain of Fol with one that causes tomato wilt. Just by sharing the same space, the inoffensive strain managed to acquire two of the extra chromosomes found in the virulent one. And, suddenly, it too could infect tomatoes. In a single event, the fungus had been loaded with a mobile armoury and changed into a killer. It seems that the fungus needs just two of the four chromosomes to cause disease; the others probably act as accessories, boosting its new pestilent powers.

Read More

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Not Exactly Rocket Science

Dive into the awe-inspiring, beautiful and quirky world of science news with award-winning writer Ed Yong. No previous experience required.
ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »