Post: Cause of Potato Famine & Why Its Coming Back
Posted by Sharon on 12/27/09
(NaturalNews) Researchers have sequenced the genome of the
fungus responsible for the Great Irish Potato Famine in the
1800s, uncovering the reason that the organism continues to
plague potato farmers to this day.
"This pathogen has an exquisite ability to adapt and
change, and that's what makes it so dangerous," said lead
researcher Chad Nusbaum of the Broad Institute in
The organism, known as Phytophthora infestans, is a type of
water mold that continues to cost potato farmers billions
of dollars every year. It prefers cool, wet climates and is
capable of destroying entire fields of potatoes and
tomatoes within only a few days. In 2003, P. infestans
destroyed Papua New Guinea's entire potato crop.
The mold evolves resistance to antifungal sprays with
astonishing speed. In just the last few years, potato
farmers in the United Kingdom have increased chemical
spraying by 30 percent in an attempt to hold the organism
at bay, and the ongoing blight in Ireland has been
called "the worst in living memory," according to the BBC.
According to information published in the journal Nature,
P. infestans' genome is especially large, at least twice as
long as the genetic code of its closest relatives. Some
regions of the genome are particularly dense, containing
many genes in a small area, while others are much less
dense. It is these gene-light areas that may hold the key
to the organism's adaptability: more than 700 key genes
were mapped in these regions, some of them coding for
attacks on potatoes' immune systems.
"The regions change rapidly over time, acting as a kind of
incubator to enable the rapid birth and death of genes that
are key to plant infection," said co-lead author Brian
Haas. "As a result, these critical genes may be gained and
lost so rapidly that the hosts simply can't keep up."
Modern agriculture has exacerbated the problem, said Paul
Birch of the Scottish Crop Research Institute. Widespread
application of chemicals encourages pest evolution, while
genetic standardization of food crops makes them more
vulnerable to infestation.
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