British design genetically-modified potato immune to blight
British scientists have designed a new strain of genetically modified potato, which appears to be immune to the devastating fungus responsible for the great Irish famine of 1845.
Late blight, caused by the organism Phytophthora infestans, remains the potato farmer’s greatest enemy to this day, with millions spend on pesticides each year to ward off the infection.
In the latest of a series of field trials, conducted in 2012, the fungus was unable to break down the defences of any of the GM potatoes.
Non-modified plants grown at the trial site were all infected after being denied protection from chemicals.
However, no-one can say at this stage how long the GM strain will hold out against blight, which is notorious for its ability to overcome resistance.
Scientists are now conducting further research aimed at identifying multiple resistance genes that will thwart future blight attacks.
“Breeding from wild relatives is laborious and slow and by the time a gene is successfully introduced into a cultivated variety, the late blight pathogen may already have evolved the ability to overcome it,” said lead scientist Professor Jonathan Jones, from The Sainsbury Laboratory.
“With new insights into both the pathogen and its potato host, we can use GM technology to tip the evolutionary balance in favour of potatoes and against late blight.”
During three years of trials, scientists grew potatoes containing a gene from a super-resistant wild strain from South America.
Normal cultivated potatoes naturally possess around 750 resistance genes, but in most varieties late blight is able to evade them.
In 2012 the researchers took advantage of a year with ideal conditions for late blight. Instead of inoculating the plants, the scientists waited for them to be infected naturally by spores blowing on the wind.
By early August, 100% of the non-GM potatoes in the study were infected. In contrast, all the GM plants maintained full resistance against the pest until the end of the experiment.
The GM plants also produced a much greater potato yield. Tubers from each block of 16 GM plants weighed in at between 6 – 13kg compared with 1.6 – 5kg for non-GM plants.
