Diversity ofPuccinia striiformison Cereals and Grasses

Abstract

Yellow (stripe) rust is a common fungal disease on cereals and grasses. It is caused by Puccinia striiformis sensu lato, which is biotrophic and heteroecious. The pathogen is specialized on the primary host at both species and cultivar levels, whereas several Berberis spp. may serve as alternate hosts. One lineage infects mainly cereals and at least two lineages are restricted to grasses. P. striiformis on cereals has a typical clonal population structure in many areas, resulting from asexual reproduction, but high diversity, suggesting frequent recombination, has been observed in certain areas in Asia. Yellow rust is spreading by airborne spores potentially across long distances, which may contribute to sudden disease epidemics in new areas. This has been the case since 2000, where large-scale epidemics in warmer wheat-growing areas have been ascribed to the emergence of two closely related yellow rust strains with increased aggressiveness and tolerance to warm temperatures.

Rapid emergence of pathogens in agro-ecosystems: global threats to agricultural sustainability and food security

“…annually or every few years) in order to impose disruptive selection on populations of crop pathogens and force them to make trade-offs among traits ( figure 1). This 'dynamic diversity' can be implemented in many ways [67][68][69][70], including improved deployment strategies for resistance genes and resistant cultivars, more frequent turnover of crop varieties that carry different resistance genes, improved deployment strategies for fungicides, more frequent crop rotations that include more species, smaller fields planted to individual crops and growing greater numbers of crop species per unit area under cultivation. The overall objective is to break up the adaptive landscape into smaller units that change on a regular basis to present the corresponding populations of crop pathogens with evolutionary dilemmas that lead to disruptive selection (figure 1).…”

Characterization of the Rust Fungus, Puccinia emaculata, and Evaluation of Genetic Variability for Rust Resistance in Switchgrass Populations

“…As experience from wheat breeding indicates, the dynamics of rust pathogen due to genetic recombination and long distance travel of spores by wind poses a constant threat to the resistant genes with reports of crop failures in different parts of the world [20][21][22]. Developing durable resistance through breeding [21] is a viable strategy which needs to be adopted for switchgrass improvement.…”

Robust cropping systems to tackle pests under climate change. A review

“…This gave rise to severe epidemics in warmer wheat production areas (Hovmøller et al 2010) where yellow rust was previously absent or infrequent, implying that current cropping systems were not prepared for the new situation. At a temperature regime typical for these areas, isolates of the new strain produced three to four times more spores per day than strains found previously (Hovmøller et al 2011). The rapid spread of the new strain is probably the cumulative result of increased pathogen fitness, warmer environments, increase in the number of spores in the atmosphere, and long-distance dispersal of these by wind, increasing travel and commerce.…”

“…Although many wheat varieties are grown in this huge area, all have a similar genetic background. With a slightly increased temperature and decreased rainfall, as observed over recent decades, a new type of yellow rust caused by Puccinia striiformis (Hovmøller et al 2011) was able to extend from Africa to India within 15 years. This has led to widespread epidemics highlighting how vulnerable an area can be when slight changes in climate occur (Wellings 2011).…”