Science News 23/05/2014

Plant researchers sow seeds of major disease breakthrough

Breakthrough research carried out by The University of Western Australia and scientists in India and China has established that oilseed varieties resistant to the devastating fungal disease Sclerotinia can be bred readily

The research, carried out by Winthrop Professor Martin Barbetti, of UWA's School of Plant Biology and Institute of Agriculture, with colleagues from India and China, could lead to Australia becoming the first country in the world to have effective host resistance to the disease in canola and mustard seed.

A paper on the research has been published in Euphytica, a prestigious international journal on plant breeding.

Disease caused by Sclerotinia devastates yield in canola, rapeseed and mustard production worldwide.  It has always been one of the most difficult diseases to manage within the plant genus Brassica.

"Until now options have relied on cultural and, increasingly, fungicidal measures that are often unreliable, costly and environmentally undesirable," Professor Barbetti said.

"Our research has identified excellent host resistances against the prevailing Sclerotinia strains, ensuring successful management based on host resistance is at last possible."

In the studies, three virulent Sclerotinia strains from WA were used to infect a broad range of canola, rapeseed and mustard breeding populations from India and China.  High levels of new, diverse, strain-specific resistances were found.

Professor Barbetti said that even more importantly, researchers also identified plant genotypes that were strain-independent in their resistance expression.  This made them ideal to exploit for the development of varieties with Sclerotinia resistance that was effective across multiple strains.

"For the first time it is possible to identify and/or breed canola, rapeseed and mustard plants that display high levels of resistance consistently," Professor Barbetti said.  "This outcome is exciting, as it can lead to the rapid development of new oilseed varieties resistant to Sclerotinia."

He said that for many years, progress towards identifying and breeding effective host resistance had been hampered by the frequent occurrence of diverse Sclerotinia strains differing in virulence.

"Where a pathogen is highly variable, breeding for resistance is very challenging," he said.  "UWA's Sclerotinia research group is the only one in the world to have developed and implemented a system that could reliably define strains of this pathogen.

"If plant breeders take up the opportunity, Australia could now be the first in the world to have effective host resistance to Sclerotinia in canola and mustard."

He said there was also potential to develop such germplasm in India and China via the partnership.

"What is more, this research could be applied to identify high levels of resistance in other forage and vegetable Brassica types, thus offering commercial solutions for related industries," he said

di R. T.