Virulence Structure of the Wheat Powdery Mildew Population in Serbia

Abstract

Powdery mildew is a common, economically important disease in the wheat growing area of Serbia. A large-scale virulence survey of its causal agent Blumeria graminis f. sp. tritici population was performed in the period 1995–2013. A total of 1013 isolates were recovered from the collected chasmothecial samples. Among them, 862 unique pathotypes were identified using a differential set of 20 wheat lines with known powdery mildew (Pm) resistant genes. The pathogen was highly diverse. Number of virulence genes (virulence complexity) per isolate was large, supporting a constant need to extend the differential set of wheat with newly identified Pm genes. Virulence frequencies to Pm6, Pm7, and Pm5+8 were high throughout the 19-year period, in contrast with that to Pm5+6, which was consistently at a low level. The most significant change in the population was observed for virulence to the Pm2+4b+6 gene combination, with an increasing frequency of virulence to this gene combination over the years. High virulence complexity and genetic diversity of the population are the most influential factors for the damaging epidemics that this pathogen can cause.

Virulence Structure and Genetic Diversity of Blumeria graminis f. sp. avenae from Different Regions of Europe

“…The structure and dynamics of changes in pathogen populations can be analysed using two different approaches. The first is based on the assessment of the virulence level of the pathogen population [ 19 , 21 , 22 , 23 , 24 , 25 , 26 ]. This approach allows us to determine the effectiveness of resistance genes used in breeding and to estimate the possibility of breaking this resistance by emerging pathogen races.…”

Development and Validation of a HTS Platform for the Discovery of New Antifungal Agents against Four Relevant Fungal Phytopathogens

“…Based on their scientific/economic importance, the top ten fungal phytopathogens have been identified [ 4 ] in rank order as (i) Magnaporthe oryzae , a phytopathogen model for plant host studies that, together with M. grisea , is one of the main causal agents of blast rice, the most destructive plant disease [ 5 , 6 , 7 ]; (ii) Botrytis cinerea , responsible for gray mold, which generates severe damages and losses in fruit, vegetables, and ornamental plants during both pre- and post-harvesting steps [ 4 , 8 , 9 , 10 ]; (iii) Puccinia spp., the cause of three types of royal diseases in Triticum aestivum which seriously impact wheat production, mainly via the infection of P. graminis , P. striiformis , and P. triticina [ 4 ]; the genus Fusarium , which includes a high number of pathogenic species, can produce numerous mycotoxins and colonize plants in a wide range of climatic areas; (iv) Fusarium graminearum , (v) Fusarium oxysporum , and Fusarium proliferatum , which can infect a broad range of crops such as maize, wheat, rice, soybean, barley, fruit, and even ornamental plants, where one of the most significant damages is root rot [ 11 ]; (vi) Blumeria graminis , which is the causal agent of powdery mildew in barley and wheat crops and is considered a high-risk pathogen because of its potential to change its virulence [ 12 ]; (vii) Zymoseptoria tritici , which is responsible for the most important wheat disease, the Septoria leave blotch, with a high percentage of infection, inducing significant damages; (viii) Colletotrichum spp., which are the genera that promote the anthracnose disease in more than 3000 plant species and can alternate between different infection stages (hemibiotrophic, necrotrophic, and biotrophic), making it very efficient in propagation and leading to considerable worldwide economic losses in fruit and vegetable crops [ 4 , 13 , 14 , 15 , 16 ]; (ix) Ustilago maydis , a homobasidiomycete that normally infects maize ( Zea mays ) through a complex pathogenic process, including morphogenetic transitions until its sexual cycle is completed [ 17 ]; and finally, (x) Melampsora lini , responsible for the rust disease on Linum usitatissimum , which causes severe losses in seed yields as well as a fiber quality reduction in flax plants [ 18 ].…”