Intraspecific genetic diversity of Drechslera tritici-repentis as detected by random amplified polymorphic DNA analysis

Abstract

The phytopathogenic fungus Drechslera tritici-repentis causes tan spot, an important disease of wheat in the southern Brazilian state of Rio Grande do Sul. Twelve D. tritici-repentis isolates were obtained from wheat seeds from different locations in the state. Their colony morphology on potato dextrose agar and polymorphisms in genomic DNA by the random amplified polymorphic DNA (RAPD) method were investigated. For the RAPD method, 23 primers were tested of which nine were selected for use in the study of D. tritici-repentis polymorphisms. The degree of similarity between isolates was calculated using a simple matching coefficient and dendrograms constructed by the unweighted pair-group method with arithmetical averages (UPGMA). The morphological and RAPD analyses showed intraspecific polymorphisms within the isolates, but it was not possible to establish a relationship between these polymorphisms and the geographical regions from where the host seeds were collected.

In Vitro Morphological Characteristics of Pyrenophora tritici-repentis Isolates from Several Algerian Agro-Ecological Zones

“…Dos Santos et al (2002) studied P. tritici-repentis , McDonald (1967) and Frazzon et al (2002) studied Pyrenophora teres isolates, and observed significant morophological variation based on mycelial colony colors. Similar results were reported by Benslimane (2002) and Christensen and Graham (1934) when they studied Pyrenophora graminea isolates for their morphological variation.…”

“…Variability among P. tritici-repentis populations was demonstrated by several workers around the world (Ali and Francl, 1998; Ali et al, 2010; Benslimane et al, 2013; da Luz and Hosford, 1980; dos Santos et al, 2002; Friesen et al, 2005; Lamari and Bernier, 1989, 1991; Leisová et al, 2008; Misra and Singh, 1972; Moreno et al, 2008; Schilder and Bergstrom, 1990; Singh and Hughes, 2006). Studying variability within the population in a geographical region is important because it documents the changes occurring in the population.…”

Genetic divergence among and within Colletotrichum lindemuthianum races assessed by RAPD

“…In this event, many data can be obtained or lost during the asexual cycle by recombination (Roca, 2004). Other factors may be linked to the genetic variability in any given study, such as the number of isolates selected for analysis, the type of organism studied, the selection pressure and migration (Santos , 2002). Phytopathogenic organisms are constantly subject to extinction and re-colonization and are rarely found in equilibrium (Peever & Milgroom, 1994).…”

Genetic Similarity among Isolates of Pyrenophora tritici‐repentis, Causal Agent of Tan Spot of Wheat

“…A preliminary study with a limited number of isolates of P. tritici‐repentis (Di Zinno et al., 1998) demonstrated high levels of polymorphisms among isolates, but found no correlation between random amplified polymorphic DNA (RAPD) polymorphism and geographic origin, toxin production or pathogenicity of the isolates. Morphological and RAPD analyses showed intraspecific polymorphism among isolates of P. tritici‐repentis , but it was not possible to establish a relationship between polymorphism and geographical origin of the isolates (dos Santos et al., 2002). To date, the extent of genetic variability among‐ and within‐races of P. tritici‐repentis of western Canada is lacking.…”