UK - Plant scientists at the John Innes Centre in Norwich have made a breakthrough that could lead to new, high-yielding, disease-resistant crop varieties.
Almost all wheat grown today is a ‘semi-dwarf’ breed from a naturally occurring mutant line with an altered giberellic acid (GA) signalling pathway.
First developed during the ‘Green Revolution’ of the 1960s, these varieties allow farmers to significantly increase crop yields because they respond to additional nitrogen by increasing yield without growing too tall and falling over (lodging) which negates the yield improvement and leads to issues with fungal infections of the heads and mycotoxin contamination of grain. The ability to increase yield per unit area has helped poorer economies to improve food security.
An added benefit of GA-defective semi-dwarf plants is that they also show increased resistance to necrotrophic fungi that kill the plant and feed from the dead tissues.
But there is a trade off because these plants are also more prone to diseases caused by biotrophic fungi that feed on living tissues.
Research into the genetic improvement of domesticated crops is difficult because they have large, complex genomes, and take up a lot of growing space. Using model species with small genomes and a compact size is useful in helping to understand crop plants, but the question remains: can what we have learned in a model be translated to a more complex species?
New research published in the journal Molecular Plant & Microbe Interactions suggests that yes, the wild grass Brachypodium distachyon is an ideal model for studying disease resistance traits in wheat and barley.
Rachel Goddard, lead co-author with Antoine Peraldi, is a PhD student in the lab of Paul Nicholson, said: “We have been investigating another plant signalling system – the brassinosteroid (BR) signalling pathway – in barley, a close relative of wheat.
"Like GA-defective plants, barley with a mutated BRI1 gene also seems to be a high yielding semi-dwarf that is more resistant to necrotrophic fungi. But in this case, the plants do not have an increased susceptibility to biotrophic fungal disease.”TheCropSite News Desk