Why is Ug99 important?

Why is Ug99 important?

Ug99 (Race TTKSK) is a cause for concern as it exhibits unique virulence patterns. No other race of stem rust has been observed to overcome so many wheat resistance genes, including the very important gene Sr31. By 2007, Ug99 (Race TTKSK) had spread via wind movements out of East Africa, into Yemen and as far as Iran.

Where is Ug99?

Pathotype Ug99 was first detected in Uganda in 1999, and subsequently reported in Kenya, Ethiopia, Sudan and Yemen. It was identified in Iran for the first time in 2007.

What type of resistance did Ug99 overcome?

Ug99 and its variants differ from other strains of the Black Stem Rust (BSR) pathogen due to their ability to overcome resistance genes in wheat that have been durable against the BSR pathogen for decades. These resistant Sr genes, of which 50 are known, give wheat different resistances to stem rust.

What does Ug99 do to wheat?

The symptoms of Ug99 wheat stem rust are identical to other wheat stem rusts in Australia. Oval or rectangular blisters running along stems and leaves. After a couple of days blisters break open to reveal a mass of rust coloured spores.

How is the Ug99 strain of wheat spreading around the world?

The fungus survives on host plants and can spread quickly over large distances by wind, movements of infected plant materials and contaminated farm machinery, equipment and clothing. Wheat stem rust can attack all above-ground parts of the plant, including the stem, leaves and inflorescence.

What do you understand by Ug99?

Ug99 is the product of a type of somatic nuclear exchange event which has not been observed in other stem rust races. During this event and thereafter the nuclei have not experienced recombination.

What type of fungus is Ug99?

Race Ug99 of the fungus Puccinia graminis tritici that causes stem or black rust disease on wheat was first detected in Uganda in 1998.

How is the Ug99 strain of wheat?

Ug99, so-named because it was found in Uganda in 1999, is a particularly virulent strain of wheat stem rust that has overcome 17 out of 34 stem rust resistance genes found in wheat. Around 30 per cent of current wheat varieties show moderate to high susceptibility to the Ug99 strain.

How is Ug99 different from other strains of black stem rust?

Ug99 and its variants differ from other strains of the Black Stem Rust (BSR) pathogen due to their ability to overcome resistance genes in wheat that have been durable against the BSR pathogen for decades. These resistant Sr genes, of which 50 are known, give wheat different resistances to stem rust.

How many Sr genes are resistant to stem rust?

These resistant Sr genes, of which 50 are known, give wheat different resistances to stem rust. The virulence in Uganda was virulent against Sr31 and is specific to Ug99.

What is the Ug99 race?

The first Ug99 race to be characterised. Like most Ug99 races, and unlike other stem rust varieties, it is virulent against the Sr gene Sr31; also virulent against Sr38. Avirulent against Sr24.

What do we know about the pathogen Ug99?

Ug99, a new pathogen race that can overcome common forms of resistance, had the capacity to cause disease in approximately 90% of the wheat population worldwide (Ayliffe et al., 2008; Singh et al., 2011 ).