Clonality in Sclerotinia sclerotiorum on Infected Cabbage in Eastern North Carolina

Abstract

Eighty-four isolates of Sclerotinia sclerotiorum from four cabbage production fields in North Carolina and 16 isolates from an experimental cabbage field plot in Louisiana were DNA-fingerprinted and tested for mycelial compatibility. In a comparison with 594 unique DNA fingerprints of S. sclerotiorum from Canadian canola, no fingerprints were shared among Canadian, North Carolina, and Louisiana populations. DNA fingerprints from the North Carolina sample were distinctive from those of the Canadian and Louisiana samples, with significantly more hybridizing fragments in the 7.7- to 18-kilobase range. Forty-one mycelial compatibility groups (MCGs) and 50 unique DNA fingerprints were identified from the North Carolina sample. Three MCGs and three fingerprints were identified from the Louisiana sample. From the North Carolina sample, 32 MCGs were each associated with a unique fingerprint; of these, there were 11 clones (i.e., cases in which two or more isolates belonged to the same MCG and shared the same DNA fingerprint). Six clones sampled from two or more fields represented approximately 29% of the total sample (24 of 84 isolates), with six clones recovered from fields 75 km apart. There were 10 cases in which one MCG was associated with more than one DNA fingerprint and two cases in which one DNA fingerprint was associated with more than one MCG. The small sample from Louisiana was strictly clonal. The North Carolina sample had a clonal component, but deviated from one-to-one association of MCG with DNA fingerprint to an extent consistent with more recombination or transposition than the other two populations sampled.

Genetic variation in New Zealand populations of the plant pathogenSclerotinia sclerotiorum

“…Some highly similar isolates indicate dispersal across the 90 km between Leithfield and Rakaia, but no recent dispersal was evident between Takaka and the other populations. Similarly, in a study of S. sclerotiorum infecting cabbages in North Carolina, dispersal between fields 75 km apart was indicated by identical clones, whereas greater distances (e.g., between North Carolina and Canada) appeared to preclude dispersal (Cubeta et al 1997). In contrast, Canadian studies found identical clones over distances up to 2000 km (Kohn 1995).…”

Mycelial compatibility and aggressiveness of Sclerotinia sclerotiorum isolates from Brazil and the United States

“…For example, some S. sclerotiorum isolates from the USA belonged to the same MCG as isolates from Canada and Switzerland, while other isolates from the USA were in the same MCG as isolates from Argentina (Kull et al, 2004). Other reports indicated lack of common MCGs in S. sclerotiorum isolates from North Carolina and Canada or North Carolina and Louisiana (Cubeta et al, 1997), and Canada, China, and England (Li et al, 2008). This lack of common MCGs may result of specific selection of MCG genotypes, due to differences in their adaptability to environmental conditions (Atallah et al, 2004;Kull et al, 2004).…”

Case Study: Sclerotinia sclerotiorum: Genetic Diversity and Disease Control

“…Prior researches on S. sclerotiorum population structure, in areas where canola, sunflower, cabbage, and other crops are grown, have shown that this pathogen populations are mainly clonal (Kohli et al, 1992(Kohli et al, , 1995Anderson and Kohn, 1995;Cubeta et al, 1997;Kohli and Kohn, 1998;Carpenter et al, 1999;Hambleton et al, 2002), even though some recombination has been detected (Cubeta et al, 1997;Carbone and Kohn, 2001a), being more evident in subtropical populations than in temperate ones (Carbone et al 1999;Carbone and Kohn, 2001b;Atallah et al, 2004;Sexton and Howlett, 2004;Sexton et al, 2006;Mert-Türk et al, 2007;Gomes et al, 2011).…”