Analysis of the Genetic Structure of Sclerotinia sclerotiorum (Lib.) de Bary Populations from Different Regions and Host Plants by Random Amplified Polymorphic DNA Markers

Abstract

The genetic diversity and genetic structure of a population of isolates of Sclerotinia sclerotiorum (Lib.) de Bary from different regions and host plants were investigated using the random amplified polymorphic DNA (RAPD) method with 20 random decamer primer pairs in order to provide some information on the phylogenetic taxa and breeding for resistance to sclerotinia stem rot. A minimum of three and a maximum of 15 unambiguously amplified bands were generated, furnishing a total of 170 bands ranging in size from 100 to 3 200 bp, corresponding to an average of 8.5 bands per primer pair. One hundred and four of these 170 bands (61.2%) were polymorphic, the percentage of polymorphic bands for each primer pair ranging from 0.0% to 86.7%. The genetic relationships among the isolates, based on the results of RAPD analysis, were examined. The genetic similarity of all selected isolates was quite high. At the species level, the genetic diversity estimated by Nei's gene diversity (h) was 0.197 and Shannon's index of diversity (I) was 0.300. The unweighted pair-group mean analysis (UPGMA) cluster analysis showed that most isolates from the same regions were grouped in the same cluster or a close cluster. The population of isolates from Hefei (Anhui Province, China) was more uniform and relatively distant to other populations. The Canadian population collected from carrot (Daucus carota var. sativa DC.) was relatively close to the Polish population collected from oilseed rape (Brassica napus L.) plants. There was no relationship between isolates from the same host plants. An analysis of molecular variance (AMOVA) revealed that the percentage of variance attributable to variation among and within populations was 50.62% and 49.38%, respectively. When accessions from China, Europe, and Canada were treated as three separate groups, the variance components among groups, among populations within groups, and within populations were -0.96%, 51.48%, and 49.47%, respectively. The genetic differentiations among and within populations were highly significant (P < 0.001). Similarly, the coefficient of gene differentiation (Gst) in total populations calculated by population genetic analysis was 0.229 4, which indicated that the genetic variation among populations was 22.94%. The gene flow (Nm) was 1.68, which indicated that the gene permutation and interaction among populations was relatively high. Key words: genetic structure; intraspecific variability; Sclerotinia sclerotiorum (Lib.) de Bary; random amplified polymorphic DNA (RAPD) analysis.Sclerotinia stem rot, also known as white mold and sclerotinia wilt, is caused by Sclerotinia sclerotiorum (Lib.) de Bary, which is a phytopathogenic fungus with a wide range and geographical distribution. It is one of the most nonspecific, omnivorous, and successful of plant pathogens (Purdy 1979). S. sclerotiorum has been

Genetic diversity and morphological variability of Sclerotinia sclerotiorum isolates of oilseed Brassica in India

“…During the study, bigger sizes of sclerotia were observed in the same morphological group and genetic cluster. Sun et al (2005) compared S. sclerotiorum Table 3. Similarity matrix generated through Jacquard coefficient.…”

Case Study: Sclerotinia sclerotiorum: Genetic Diversity and Disease Control

“…Sun et al (2005) reported that the relationship between Canadian and Polish populations of S. sclerotiorum was very close, although the geographic distance between them was large. Also, Li et al (2009) analyzed five populations of S. sclerotiorum isolated from sunflower in three countries, Mongolia, in China, Canada, and the United Kingdom.…”

“…Several reports concerning the population structure of S. sclerotiorum in Asia are available: Iran (Hemmati et al, 2009;Barari et al, 2010Barari et al, , 2011Colagar et al, 2010;Karimi et al, 2011), Jordan (Colagar et al, 2010); Pakistan (Akram et al, 2008), Turkey (Mert-Türk et al, 2007;Yanar and Onaran, 2011) and China (Sun et al, 2005;Li et al, 2008Li et al, , 2009Chen et al, 2010). Different vegetable crop fields were analyzed in these studies and most authors came to the general conclusion that populations exist somewhere in the spectrum between sexual outcrossing and clonal.…”

“…MCGs or microsatellite markers have not been associated with specific virulence characteristics or ecological adaptations of the pathogen, and lack of variation in virulence among isolates from defined geographic areas has been reported in a number of studies on agricultural populations (Kohn et al, 1991;Kohli et al, 1992;Cubeta et al, 1997;Atallah et al, 2004;Auclair et al, 2004;Kull et al, 2004;Sexton and Howlett, 2004;Sun et al, 2005;Malvárez et al, 2007;Litholdo Júnior et al, 2011). Sexton and Howlett (2004) reported that among 44 isolates tested for virulence, the only two ones that caused relatively small leaf lesions were originally cultured from stem lesions rather than petals.…”

Genetic diversity and mycelial compatibility groups of the plant-pathogenic fungus Sclerotinia sclerotiorum in Brazil

“…In general, clonal reproduction has been shown to be predominant in temperate climate regions, whereas sexual recombination contributes to population structure in milder climates (Cubeta et al, 1997;Kohli and Kohn, 1998;Carpenter et al, 1999;Atallah et al, 2004;Sun et al, 2005;Malvárez et al, 2007;Arbaoui et al, 2008). Individual isolates are classified into clonal lineages by the use of two or more independent markers, such as mycelial compatibility groups (MCGs), DNA fingerprinting, or microsatellites (Kohn et al, 1991;Carbone et al, 1999;Sirjusingh and Kohn, 2001;Hambleton et al, 2002;Auclair et al, 2004).…”