The discoveries were made by scientists working for the UK's Biotechnology & Biological Sciences Research Council crop science initiative and were revealed at a reception in London last week.
Researchers from the University of Dundee, the Scottish Crop Research Institute and the University of Aberdeen have come up with a promising new approach to breeding resistance to late blight, which costs the potato and tomato industries £5bn-£6bn a year worldwide.
Meanwhile, a team from the University of Warwick has identified the major gene involved in the resistance to the turnip mosaic virus (TuMV), which is known to affect brassica crops including broccoli, cauliflower, cabbage, kale, swede and oilseed rape.
Professor Paul Birch from the University of Dundee, who led the late blight research project, explained that his team broke with the tradition of attempting to breed resistance to the blight by identifying those plants that have survived periods of infection.
Instead, they examined the behaviour of the mould-like organism (Phytophtora infestans) itself and how it interacts with potato plants, and identifying the proteins secreted by the pathogen that play an essential role in infecting the plants.
Birch said: "We now know a lot more about how P. infestans gets round the potato plant's natural defences and what it takes for the plant to resist infection. We can actually look at a potato plant's genetic make-up and say whether it will be sustainably resistant to late blight, which is a huge step forward. While our approaches are suitable for breeding, in future we also hope to use a GM approach to produce a variety that is resistant to both blight and potato cyst nematode."
This work will be taken forward in a new project with colleagues at the Sainsbury Laboratory in Norwich to identify resistance in potato plants that could then be used for breeding new resistant varieties.
Potato Council head of research and development Dr Mike Storey said: "Blight is serious problem for the potato industry in the UK. We are working hard to ensure growers' awareness and best practice to control the disease, but we have the challenge of a continually changing pathogen population.
"What we need now is the application of this new research to improve variety resistance and identify new crop protection targets, and integrate these approaches for sustainable control."
The TuMV team led by Dr John Walsh of the University of Warwick found that the way in which the TuMV-resistant gene creates this resistance is completely new.
Using this knowledge they found that it was possible to identify plants with an inherent resistance that could be used to speed up the breeding process and develop commercial varieties that are resistant to TuMV.
The University of Warwick has now teamed up with industry partner Syngenta Seeds to breed resistance into Chinese cabbage and hopes in future to do the same with other crops such as broccoli, cabbage and kale.
Syngenta Seeds leafy crops global R&D lead Peter van der Toorn said: "Working in partnership with academic researchers is very important for us. Through such collaborations it's possible to take an idea from pre-commercial research and turn it into a new variety that can benefit the consumer and boost our contribution to the UK economy."