Characterization of Armillaria heimii from Africa

Abstract

Armillaria heimii is one of the most widespread Armillaria species recorded in Africa. The species was originally described as Clitocybe ( Armillariella ) elegans Heim, and was renamed as Armillaria heimii Pegler; this name was subsequently made synonymous with A. fuscipes Petch to represent as a single morphological species. Recent molecular work has suggested that isolates previously identified as A. heimii were distinct and may represent A. fuscipes or another Armillaria species. A collection of isolates that had been identified as A. heimii from different African countries were included in an integrated study that included amplified restriction-length polymorphism (AFLP) fingerprinting, polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP), sequencing, induction of basidiomata in vitro and somatic compatibility, in order to determine their identity. Although the isolates could be assigned to one of two molecular groups, the morphology and somatic compatibility characters suggested that the two groups represent different forms of a single species that closely matches the original description of A. heimii .

Molecular phylogeny of Armillaria from the Patagonian Andes

“…For these reasons, DNA-based molecular techniques have been applied in Armillaria taxonomy, either complementing other methods or on their own. The techniques utilised for the taxonomy of Armillaria species include comparisons of restriction fragment length polymorphisms (RFLPs) (Harrington and Wingfield 1995) amplified fragment length polymorphisms (AFLPs) (Pérez-Sierra et al 2004), and the use of sequences from the internal transcribed spacer regions (ITS), intergenic spacer region one (IGS-1) and partial elongation factor one alpha (EF1-α) gene in phylogenetic studies (Coetzee et al 2000(Coetzee et al , 2001Maphosa et al 2006;Kim et al 2006).…”

Armillaria species on tea in Kenya identified using isozyme and DNA sequence comparisons

“…Results of this study using isozyme analyses, RFLP patterns and comparisons of DNA sequence data showed that Armillaria from diseased tea bushes in Kenya represent three distinct groups. These results are in agreement with previous investigations that have found a variety of Armillaria groups in Kenya (Mwangi et al ., 1989, 1994; Mohammed et al ., 1994; Otieno et al ., 2003b; Pérez‐Sierra et al ., 2004). In the present study, these groups are referred to as Kenyan groups I, II and III.…”

“…Pérez‐Sierra et al . (2004) showed that isolates that they referred to as A. heimii from Africa, which also included various samples from Kenya, can be separated into two groups based on PCR amplicon size and RFLP profiles.…”

“…This has motivated the use of molecular‐based studies to identify and classify isolates. Recent studies using analyses of pectic enzymes, DNA sequences, and RFLP and AFLP profiles have suggested that several species other than those previously recognized may be present in Africa (Mwenje & Ride, 1996, 1997; Coetzee et al ., 2000a; Mwenje et al ., 2003; Otieno et al ., 2003b; Pérez‐Sierra et al ., 2004).…”

“…Armillaria fuscipes encompassed isolates previously characterized and referred to as A. heimii (Coetzee et al ., 2000a). The separation of the lineages, reflecting A. fuscipes and A. heimii , into species, and the application of the names to identify them subsequently evoked considerable debate (Otieno et al ., 2003b; Pérez‐Sierra et al ., 2004). Recently, Coetzee et al .…”