John Innes Centre seeks crop resistance to flea beetle pests

Norwich scientists are delving into the DNA of oilseed rape crops to find ways to make them less palatable to voracious beetle pests.

Dr Rachel Wells outlined the exhaustive work being undertaken at the John Innes Centre (JIC) to breed resistance to cabbage stem flea beetles, during a farmers' meeting hosted by agricultural company Frontier.

The destructive feeding of the beetle and its larvae on emerging oilseed rape plants has been an increasing concern for growers ever since neonicotinoid pesticides were banned by the EU due to fears over their impact on bees.

But the JIC is part of a £1.8m project to find alternative solutions, by identifying plant traits which influence the beetle's feeding habits, and mapping these resistance genes so they can be incorporated into commercial crop varieties.

A cabbage stem flea beetle on an oilseed rape plant - Picture: Dewar Crop Protection

This involves breeding a continous population of captive beetles for an array of replicated studies on how larvae and adults of different ages and genders feed on various oilseed rape varieties.

The amounts of leaf consumed are calculated to show which varieties are most palatable to pests - data which is then compared to the plant's genome sequence.

"Where we see these peaks, we see a region of the genome that is associated with controlling that palatability within the flea beetle," said Dr Wells.

"So we can work out what genes are underneath this peak, and if we have any difference between resistant cultivars and susceptible cultivars that leads to a change in palatability.

John Innes Centre scientist Dr Rachel Wells is researching the resistance of oilseed rape crops to pests - Picture: Newsquest

"Some [seed] breeders have got material that is quite palatable to the beetle, but we also have some that is actually quite resistant.

"Hopefully that gives you some hope that there is some stuff out there that the beetles would prefer not to eat."

Other experiments are exploring changes in gene expression which control the plant's defence mechanisms, and leaf surface compounds which affect feeding levels.