Rhynchosporium commune: a persistent threat to barley cultivation

Abstract

The main measure for the control of R. commune is the use of fungicides with different modes of action, in combination with the use of resistant cultivars. However, this is constantly under review because of the ability of the pathogen to adapt to host plant resistance and to develop fungicide resistance.

Is Zymoseptoria tritici a hemibiotroph?

“…At the end of the growing season the fungus destroys the crown tissue and becomes necrotrophic (Rouxel and Balesdent, 2005). Even more extreme is Rhynchosporium commune, causal agent of barley scald, which grows asymptomatically for long periods and can sporulate before appearance of visual symptoms (Avrova and Knogge, 2012). All of these pathogens are classified as necrotrophs, and they appear to colonize the apoplast as endophytes rather than as biotrophs prior to the induction of necrotic symptoms (Stotz et al, 2014).…”

Differences in MAT gene distribution and expression between Rhynchosporium species on grasses

“…Leaf blotch (scald), caused by fungal pathogens in the genus Rhynchosporium , is an important disease of barley ( Hordeum vulgare ), rye ( Secale cereale ) and other graminaceous species (Brooks, ; Avrova & Knogge, ). This globally distributed disease of barley crops (Brooks, ) is estimated to cause annual losses of £10·8 million to United Kingdom (UK) barley crops alone, despite extensive use of fungicides (Zhan et al ., ; Anonymous, ; King et al ., ).…”

“…The mode of reproduction is a critical factor in understanding the population biology of plant pathogenic fungi because this impacts on the possibility for recombination and evolution of the pathogen (Milgroom, ; McDonald & Linde, ). In particular, a sexual cycle for R. commune has not yet been identified under either natural or laboratory conditions (Avrova & Knogge, ). However, R. commune isolates have been shown to have a mating‐type ( MAT ) locus resembling that of species with a heterothallic (obligate out‐crossing) sexual mating system (Foster & Fitt, ; Linde et al ., ), with isolates of complementary mating type (referred to as MAT1‐1 and MAT1‐2 ) present, which could enable sexual reproduction to occur.…”

Evolutionary Relationships between Rhynchosporium lolii sp. nov. and Other Rhynchosporium Species on Grasses

“…This equates to an estimated UK national yield loss of £10.8 million per annum (at a price of £225/tonne) despite fungicide treatment [4]. The symptoms of Rhynchosporium colonisation of barley can include coalescing lesions with dark brown margins and pale green or pale brown centres [5].…”