Plant Biotech Blog

Scientists at the Laboratory of Plant Breeding at Wageningen University in the Netherlands have developed a method to identify and isolate genes to make potatoes resistant to Phytophthora infestans, also know as potato blight. The new method allows scientists to target more than one gene with the resistance, leading to hopefully more success. Scientists in the UK and US are also helping on this project.

Dr. C Kameswara Rao

New method discovered to make potatoes resistant to Phytophthora
CheckBiotech.org
August 8, 2008

Dutch, British and American scientists have developed a method to more quickly identify and isolate genes that can be used to make potatoes resistant to Phytophthora infestans, the dreaded potato blight. With this method, multiple resistance genes from different species of potatoes can be isolated and possibly used simultaneously. This offers the prospect of achieving sustainable resistance against the pathogen because it is less capable of breaking the resistance of the potato when multiple genes are involved.

According to researchers at Wageningen University in the Netherlands, the Sainsbury Laboratory at the John Innes Centre in the UK and Ohio State University in the USA, the best strategy to make potatoes resistant to the stubborn fungal pathogen Phytophthora is to develop so-called broad spectrum resistance. In their article, published on 6 August in the journal PLoS One, they explained that the current methods to discover resistance genes are too slow. Moreover, because they often concern only a single gene, these methods do not lead to sustainable resistance because Phytophthora can break single-gene resistance relatively quickly and easily.

Interaction

The newly developed method is based on the interaction of genes of the pathogen and genes of the potato. The response of the potato involves resistance genes in the plant, and the response of P. infestans involves so-called avirulence genes. The avirulence gene produces proteins (effectors) that are recognised by the resistance gene proteins of the potato; an interaction then takes place. By using effectors (proteins that are secreted by Phytophthora into the plant after infection takes place), researchers can relatively quickly identify and isolate the genes that are crucial to the interaction. Because the pathogen (Phytophthora) cannot switch off these proteins, but produces them constantly, genes that can recognise these proteins can potentially serve as resistance genes.

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