Diversity of oat crown rust (Puccinia coronata f.sp. avenae) isolates detected by virulence and AFLP analyses

Abstract

Klenová-Jiráková H., Leišová-Svobodová L., Hanzalová A., Kučera L. (2010): Diversity of oat crown rust (Puccinia coronata f.sp. avenae) isolates detected by virulence and AFLP analyses. Plant Protect. Sci., 48: 98-106.Forty Puccinia coronata f.sp. avenae isolates from several European countries and Israel were tested for virulence to 18 differential oat lines. Amplified Fragment Length Polymorphism (AFLP) analysis was used to evaluate diversity among the studied isolates. Twenty-nine different pathotypes were identified. The prevailing occurrence of pathotypes with a limited number of virulence genes may indicate that oat cultivars grown in Europe possess the limited number of resistance genes. A total of 501 AFLP polymorphic fragments were scored in the studied isolates using twelve primer combinations. All isolates had the unique AFLP molecular pattern. The genetic similarity of isolates from Serbia. Austria and from the Czech Republic indicates that oat crown rust urediniospores may often migrate to particular areas. The number of virulence genes in isolates also seems to play an important role in the clustering. Most isolates possessing a lower number of virulence genes (0-4) were grouped into two clusters, whereas another cluster was composed of a majority of isolates with 4-7 virulence genes. A significant correlation relationship of 0.187 (P = 0.007) was found between AFLP and virulence/avirulence genes based on distance matrices.

Puccinia coronata f. sp. avenae: a threat to global oat production

“…Klenová‐Jiráková et al . () used an amplified fragment length polymorphism (AFLP) analysis to evaluate the genetic diversity of 40 Pca isolates collected from seven different countries (Israel, Czech Republic, Belarus, Estonia, Hungary, Austria and Serbia), which confirmed the high genetic diversity of the species, as each isolate presented a unique AFLP molecular pattern, although genetic similarity was found for those isolates from the Czech Republic, Austria and Serbia. To our knowledge, simple sequence repeat‐expressed sequence tag (SSR‐EST) markers have only been developed to study the genetic diversity of Puccinia coronata f. sp.…”

“…However, in the northern USA, where buckthorn is abundant, inoculum from the alternative host probably plays a more important role in crown rust outbreaks than do urediniospores carried through the Puccinia pathway (USDA‐ARS CDL, ). The northward movement of crown rust inoculum also occurs in Europe (Klenová‐Jiráková et al ., ; Simons, ). Moreover, migrating birds have been shown to play a role in both the northward and southward dispersal of spores during spring and autumn, respectively, and even across continents (da Silva et al ., ; Warner and French, ).…”

“…Nonetheless, it is evident that virulence profiles can vary greatly amongst isolates of Pca, and this can only be explained by the existence of distinct effector/Avr gene repertoires in the pathogen. As documented by national and international surveys, Pca is one of the most pathogenically diverse cereal rust fungi, exhibiting the rapid emergence of new virulent isolates (Carson, 2011;Chong and Kolmer, 1993;Klenov a-Jir akov a et al, 2010;Park, 2008;Simons, 1985). Pathogen characterization is conducted on a set of oat genotypes carrying one or more Pc genes in various genotypic backgrounds to define pathogenicity based on compatible (virulent) or incompatible (avirulent) interactions, each assigned to a physiological race Leonard et al, 2004;van Niekerk et al, 2001).…”

“…In Australia, surveys from 1998 to 2010 identified more than 100 Pca races, much higher than found for the same period of time in other cereal rust species that are also not sexually active (Park, 2008;Park and Wellings, 2012). These observations raise questions about the role of buckthorn in the pathogenic diversity of Pca and whether other factors, such as repeated introductions, high mutation rates or somatic hybridization and recombination, are also important contributors to the diversity and virulence in Pca populations (Bartos et al, 1969;Klenov a-Jir akov a et al, 2010;Park and Wellings, 2012;Simons, 1970). It is possible that the genetic diversity of Pca, resulting from the re-assortment of pathogenicity factors through sexual reproduction, can be further enhanced by multiple molecular mechanisms that introduce variability into asexual populations (Simons, 1985).…”

Intact spore MALDI-TOF mass spectrometry and proteomic analysis of Puccinia pathogenic fungi

“…In the Czech Republic, three species infecting wheat are well studied: Puccinia triticina, Puccinia graminis and Puccinia striiformis [3]. Among other important rust fungi, Puccinia coronata causes the most damaging disease on oats and has probably been pathogenic since the plant was first cultivated [4]. Within one Puccinia species, there are often specialized forms (formae specialis; f.…”