Analyses of RAPD data for detection of host specialization in Sclerotinia homoeocarpa

Abstract

UPGMA analysis, principal component analysis, genetic diversity analysis and genetic distance analysis of RAPD data were used to assess the extent of host specialization in 50 isolates of S. homoeocarpa from five turfgrass hosts. In UPGMA analysis and principal component analysis, the occurrence of host specialization was not readily apparent based on visual inspection. Genetic diversity analysis showed significant differentiation among isolates from different host species (G ST ¼ 0·34, P < 0·001). The strongest evidence for some degree of host specialization came from the statistical analysis of genetic distances among isolates. By grouping pairwise genetic distances between isolates based on their host species, and analysing for average distance within the same host species and among different host species, it was found that the average distance within species was less than among species (P < 0·0001). An analysis of molecular variance of the genetic distances among isolates found that 32·3% of the total variation was attributable to host species. It is concluded that these isolates of S. homoeocarpa showed a weak level of host specialization, which was not readily apparent by UPGMA or principal component analyses, but was revealed by genetic diversity analysis and statistical analysis of genetic distances among isolates. Inoculation tests on different host species and tests using a greater number of isolates are required to confirm the extent of specialization.

Cultivation and Topdressing Requirements for Thatch Management in A and G Bentgrasses and Creeping Bluegrass

“…The dramatic differences in occurrence of dollar spot among the bentgrasses disagreed with results from the southeastern U.S. which reported 'A-4 , 'G-2 , and 'Penncross all had relatively good dollar spot resistance (Bruneau et al, 2001). Our results may have differed due to different strains of the pathogen, though the limited evidence available suggests pathogenicity of S. homeocarpa isolates varies according more to host species rather than cultivar (Hsiang et al, 2000). However, other data from trials in various regions of the United States have also noted a lack of dollar spot resistance in 'A-4 compared to 'Penncross , similar to results in our study (NTEP, 1997).…”

Genetic diversity ofPoa pratensisL. depending on geographical origin and compared with genetic markers

“…In grasses, RAPD and ISSR markers are most commonly used to evaluate genetic variability within and between populations, and for molecular characterization and identification of different species and their hybrids, cultivars and genotypes ( Posselt et al, 2006 ; Pivorienė et al, 2008 ; Al-Humaid, Ibrahim & Motawei, 2011 ; Motawei & Al-Ghumaiz, 2012 ; Madesis et al, 2014 ; Yuan et al, 2014 ). In P. pratensis , genetic analyses employing RAPD and ISSR focus mainly on the identification of sexual and apomictic genotypes ( Huff & Bara, 1993 ; Mazzucato et al, 1995 ; Barcaccia et al, 1997 ; Barcaccia, Veronesi & Falcinelli, 1998 ; Stephens et al, 2006 ); the assessment of genetic variability and identification of genotypes and cultivars ( Lickfeldt, Voigt & Hamblin, 2002 ; Ning et al, 2005 ; Liang et al, 2009 ; Fard et al, 2012 ; Wang et al, 2012 ; Yuan et al, 2015 ); determining the genetic relationships between different genotypes and species belonging to the genus Poa and their hybrids ( Johnson et al, 2002 ; Curley & Jung, 2004 ; Patterson, Larson & Johnson, 2005 ; Goldman, 2008 ; Goldman, 2013 ); and identification of pathogens responsible for fungal diseases in grasses ( Hsiang et al, 2000 ). Both marker systems can generate high resolution band patterns and high levels of polymorphism as high as 90%.…”

Characterization of morphological traits and RAPD polymorphism in selected forms of Kentucky bluegrass (Poa pratensis L.)

“…Kuntze, Agrostis stolonifera L., Agrostis spp., Poa annua, Poa compressa and Poa pratensis (Caetano-Anollés 1998;Al-Humaid & Motawei 2004;Ning et al 2005;Fard et al 2012). RAPD analyses of Poa pratensis, primarily, focused on: identification of sexual and apomictic genotypes (Huff & Bara 1993;Mazzucato et al 1995;Barcaccia et al 1997Barcaccia et al , 1998Stephens et al 2006), assessment of genetic diversity, identification of different genotypes and cultivars (Lickfeldt et al 2002;Al-Humaid & Motawei 2004;Ning et al 2005;Liang et al 2009;Fard et al 2012;Wang et al 2012), attempts to determine the genetic relationships between different genotypes and species belonging to the genus Poa (Johnson et al 2002;Curley & Jung 2004;Patterson et al 2005), and identification of pathogens responsible for fungal diseases in grasses (Hsiang et al 2000). As evidenced by the results of research presented in the literature (Johnson et al 2002;Ning et al 2005;Rajasekar et al 2005;Szenejko et al 2009;Szenejko 2013) various forms of Poa pratensis are characterized by a high level of band polymorphism, estimated to be over 80%.…”