Scientists have developed and improved technique for capturing longer DNA fragments, doubling the size up to 7000 DNA bases that can be analyzed for novel genes which provide plants with immunity to disease.
Together with colleagues at the Earlham Institute and The Sainsbury Laboratory, researchers at the James Hutton Institute have found a new way to decipher these large stretches of DNA to discover and annotate pathogen resistance in plants.
By using the RenSeq method, scientists are able to sequence Resistance (R) genes that confer disease resistance in plants. Each plant typically carries hundreds of potential R gene sequences, encoding NB-LRR proteins, identified by the presence of specific sequence motifs. R genes are often part of families of closely related sequences.
While shared sequences make it possible to capture the R-genes, it also makes it hard to tell them apart and find the exact gene that enables plants to survive attack. Longer molecules and sequences of DNA allow easier and more accurate genetic analysis to identify variation.
The NB-LRR gene family enables plants to withstand infection from a suite of diseases and form a second line of defense. After a pathogen has managed to invade a plant, it uses ‘effector’ molecules to weaken a plant’s defenses - the R gene proteins recognize these ‘effector’ molecules and signal to the plant to activate defense responses - killing cells around the site of infection in an attempt to stop it spreading.