Analysis of some of the Black and Yellow Lingzhi in Magoderna Stey. and Tomophagus Murr. and related groups newly-found from South Vietnam - intermediate forms of Amauroderma & Ganoderma
The second species of Tomophagus and the type of Magoderna from Cattien National Park, a UNESCO World Heritage Centre located about 150 km north west of Ho Chi Minh City (Saigon) in southern Vietnam were reported and analysed comparatively in details with many related groups showing them as intermediate forms between Amauroderma and Ganoderma in the Ganodermataceae Donk.
Analysis of some of the Black and Yellow Lingzhi in Magoderna Stey. and Tomophagus Murr. and related groups newly-found from South Vietnam - intermediate forms of Amauroderma & Ganoderma
Le XuanTham1, Nguyen Le QuocHung1, Pham Ngoc Duong2, Dang Ngoc Quang3, Duong Van Hop4, Bui Thi Luong4 and JM Moncalvo5
1Department of Science & Technology of Lam dong Province
2National Park of Cattien, Dongnai Province
3University of Pedagogy, Hanoi
4National University of Hanoi
5Toronto University, Royal Ontario Museum, Canada
1.Systematics
Tomophagus colossus was described by Fries (1851) from Costa Rica as P. colossus andlater transferred to Ganoderma by Baker (1918) with specimens from South East Asia. It is a rare species but it appears to be pantropical in distribution although not recorded from East Africa (Ryvarden and Johansen, 1980; Ofodile et al., 2005). In Vietnam, it was first recorded by Patouillard (1897) as Ganoderma obokense, a species described from Somalia and a synonym of G. colossum (Furtado, 1965; Steyaert, 1972; Ryvarden and Johansen, 1980; Ryvarden, 2004), and recently rediscovered by Ngo Anh et al. (2001). This species is easy to recognize from its thin yellow crust and a pale and chalky context. It is rarely found but widespread, reported from the neotropics including Florida (Gilbertson and Ryvarden, 1986), tropical Africa (Ryvarden and Johansen,1980), the Arabic Peninsula (Al Bary et al., 2002), Malaysia and Indonesia (Corner, 1983), South China (Wu et al., 1998), and Taiwan (Wu et al., 2003). Murrill (1905a,b) created the genus Tomophagus to segregate G. colossum (Fr.) C.F. Baker from Ganoderma based on its unusually thick and pale context that becomes soft and light when dry. Tomophagus was not accepted by most later authors. Steyaert (1980) even suggested that G. colossum may be a temperate variant of G. oregonense Murrill, a species that also has a soft and pale context. However, recent molecular phylogenetic studies that used sequence data from the nuclear ITS rDNA (Moncalvo et al.; 1995; Moncalvo, 1996) and the D region of the mitochondrial rDNA small subunit (Hong and Jung, 2004) indicate little relationship between G. colossum and G. oregonense and support a generic distinction of Tomophagus. T. cattienensis was suggested and distinguished from T. colossus by shining glossy light red brown pileus and bulky short stipitate – pleuropodal, also glossy dark red brown, and the context quite harder (Le Xuan Tham et al., 2008). Chlamydospores of T. cattienensis are particularly distinguished from T. colossus by larger spherical body and thicker wall and coarser cylindric spines (longer and bigger).
Basing on morphological characters of fruit bodies, there are controversial arguments on the treatments of taxonomy of a rare Black Lingzhi fungus, either Ganoderma subresinosum (Murr.)Humphrey, Magoderna subresinosum (Murr.) Steyaert, Trachyderma subresinosum (Murr.) Imazeki, (Humphrey, 1938; Imazeki, 1952; Steyaert, 1972,…), or Amauroderma subresinosum (Murr.) Corner, based on Fomes subresinosum Murril (Corner, 1983; Moncalvo et Ryvarden, 1997; Zhao et Zhang, 2000,…). Steyaert described and designed this species as the type of the genus Magoderna (using an anagram from Ganoderma). Upper surface at first red-brown (young fruitbodies) become black, sublaccate, the context is quite ivory white, whitish later becoming faintly pinkish brown or greyish, and the layer of tubes is quite whitish yellow or cinnamon. When fresh the context of Magoderna subresinosum somewhat similar to that of Tomophagus cattienensis and T. colossus, but become so hard and heavy when dry. Basidiospore structures are well shown typically intermediate between amaurodermoid and ganodermoid forms: subglobose with minimized or non-aperture (germpore) and very thin quite non-double wall, but with a hillum on the bottom (attachment to sterigma on basidia).
In cultivations, fruiting bodies of T. cattienensis develop in 65-75 days or more, that is 20-25 days longer than for T. colossus and Ganoderma isolates, and fruiting bodies of Magoderna subresinosum develop in 70-85 days or more, longer than other Amauroderma species.
2. Characterisations in composition of bioactive ingredients
Ganoderma triterpenoids and derivatives are pharmacologically active and their therapeutic use is being investigated. Recent studies have reported new lanostane triterpene lactones (colossolactones) from the cultivated T. colossus strain ANH s.n. from Vietnam (Kleinwachter et al., 2001; El Dine et al., 2008). Colossactones were also present in a Nigerian strain (Ofodile et al., 2005). Thererefore, the discovery of a novel species of Tomophagus, T. cattienensis, may have implications for the discovery of novel bioactive compounds for pharmaceutical use.
For the first time, phytochemical compositions of the fruit bodies of Amauroderma subresinosumum have led to the isolation and structural elucidation of five fatty acids as Pentadecanoic acid (C15H30O2) (4%), 14-Methyl pentadecanoic acid (C16H32O2) (24%), 9,12-Octadecadienoic acid (C18H32O2) (19%), 9-Octadecenoic acid (C18H34O2) (42%) and Octadecanoic acid (C18H36O2) (10%), unknown from any Ganoderma species up to date, together with a mixture of steroids and sugars, and some derivatives of triterpenoids. Their structures were elucidated by a combination of 1D NMR and GC-MS. These results support a new and further taxonomy of the Ganodermataceae family, in which Magoderna subresinosum is designated in the distinctive genus separated from Ganoderma and Amauroderma, due to mainly poor derivatives of triterpenoids, that are commonly found from Ganoderma species, particularly in G. lucidum complex.
3. Speciations in rDNA
The second species of Tomophagus from Cattien National Park. Distinction between the new species reported here and T. colossus is based on combined evidence from morphology, cultural characteristics, and ITS rDNA barcodes.Phylogenetic analysis and ITS rDNA barcodes also clearly distinguish between the two species. MP analyses yielded a single tree and indicated 100% bootstrap support for the distinction between T. cattienensis and T. colossus. Pairwise inter-specific difference was observed in 27-33 nucleotide positions (4.83 - 5.91%), whereas intra-specific divergence was much lower: the two T. cattienensis collections from Vietnam differ in only 6 nucleotide positions (1.08%), and our four Asian samples of T. colossus differ in 1-10 positions (0.18-1.8%). These values for intra- and inter-specific variation in fungal ITS sequences are in agreement with the study by Nilsson et al. (2008) and confirm the view that ITS can be a good molecular marker (DNA barcode) for species identification in fungi.
Molecular examinations of rDNA with nearly complete sequencing D1, D2 regions (26S) have revealed that these taxa are separated from the Ganoderma species. The sequences of rDNA 26S of Magoderna subresinosum and Amauroderma species are quite similar to Tomophagus. However, the sequences of ITS1 and ITS2 (5.8S) are so diverse. While the ITS1 shares high similarity with Ganoderma species, the ITS2 shows very close relationship with Amauroderma. It should be explained that these taxa would be intermediate speciations derived from Ganoderma, and Magoderna Stey. and Tomophagus Murr., if revised and recovered, should evolved similar species and placed in the transient positions between genera Amauroderma and Ganoderma with many representatives and related groups incl. Humphreya and Haddowia just studied in phylogeny of the Ganodermataceae Donk.
Corresponding author for oral presentation: Le Xuan Tham, Ph.D.Assoc.Prof.
Vice Director, Department of Science & Technology, Lamdong Province
35 Tran Hung Dao Street, Dalat City, Lamdong Province, Vietnam
E-mail : thambiotech@yahoo.com