Asperphenamate (= asjanin = anabellamide = auranamide) was first discovered from Aspergillus flavipes by Clark et al. (1977) and Clark & Hufford (1978) and later reported from Penicillium brevicompactum (Doerfler et al., 1981; Bird & Campbell, 1982a, b; Bringmann et al., 2010; Frisvad et al., 2004), Penicillium bialowiezense (Frisvad et al., 2004), Penicillium olsonii (Frisvad et al., 2004), Penicillium megasporum (Nozawa et al., 1989), Penicillium soppii (Frisvad et al., 2006), Penicillium canadense = P. arenicola = Phialomyces arenicola (McCorkindale et al., 1978; Houbraken & Samson, 2011), Aspergillus janus (Nakashima et al., 1983; as asjanin), Aspergillus allahabadii, Aspergillus carneus and Aspergillus microcysticus (Samson et al., 2011) and Talaromyces thailandense (Dethoup et al., 2007). These species all belong to the Trichocomaceae (Houbraken & Samson, 2011). However, asperphenamate has also been found in a series of unrelated plant species: Anaphalis subumbellata (Compositae), Artemisia anomala (Asteraceae), Begonia nantoensis (Begoniaceae), Cantharanthus pusillus (Apocunaceae), Croton hieronymi (Euphorbiaceae), Desmos longiflorus (Annonaceae), Dorstenia dinklagei (Moraceae), Ficus mucoso (Moraceae), Grangea maderaspatana (Compositae), Leucas aspera (Lamiaceae), Medicago polymorpha (Fabaceae), Melastroma malabathricum (Lamiaceae), Miliusa velutina (Annonaceae), Piper aurantiacum (Piperaceae), Piptadenia gonoacantha (Leguminosae), Saurauia napaulensis (Actinidiaceae), Uvaria ufa (Annonaceae), Wikstroemia indica (Thymelaceae) and Zeyhera digitalis (Bignoniaceae) (Battersby & Kapil, 1965; Banerji & Ray, 1981; Wu et al., 2004; Talapatra et al., 1983; Poi & Anityachoudhury, 1986; Jakupovic et al., 1987; Singh & Jain, 1990; Catalán et al., 2003; Bankeu et al., 2010; Geng et al., 2006; Pomini et al., 2006; Sandhu et al., 2006; Vouffo et al., 2008; Xiao et al., 2007; Carvalho et al., 2010; Macabeo et al., 2010; Sirat et al., 2010) leading to the suggestion that asperphenamate may be produced by endophytic fungi rather than plants (Macabeo et al., 2010). Asperphenamate has recently attracted much interest because of its antitumor (Wu et al., 2004; Yuan et al., 2010, 2012; Li et al., 2012) and antimicrobial activity. Furthermore, filamentous fungi are more sustainable and efficient industrial producers of secondary metabolites than the plants, so there is interest in finding further, perhaps more efficient producers of asperphenamate among the fungi. In our studies, on the biodiversity of Penicillia, we found a large number of isolates producing a rich profile of extrolites including asperphenamate. In addition, we found that these strains grow well at lower temperatures and are halotolerant.
Growth in cold habitats often involves the ability to grow at low water activities because liquid water is only partially available in ice and maybe xerophile plays a role in psychrophily or psychrotolerance (Petrovič et al., 2000; Gunde-Cimerman et al., 2003). In contrast to Aspergillus and its teleomorphs, no genuinely halotolerant species have been described in Penicillium. However, several species do grow better on Czapek yeast agar (CYA) with 5% NaCl than without (Frisvad & Samson, 2004; Frisvad, 2005; Houbraken et al., 2011). Many Penicillium species grow just as well or slightly slower at 15 °C than at 25 °C. The number of Penicillium species that grow better at 15 °C than at 25 °C is more limited, and these include Penicillium thymicola, Penicillium verrucosum, Penicillium marinum, Penicillium nothofagi and Penicillium wellingtonense (Frisvad & Samson, 2004; Houbraken et al., 2011). Until now, only Penicillium jamesonlandense has been described as psychrotolerant, and this species grows slowly or not at all at 25 °C and this thus is close to being psychrophilic (Frisvad et al., 2006).
We have encountered a large number of isolates that grow very slowly on CYA and other media at 25 °C but that grow significantly faster either at 15 °C or with 5% NaCl in the growth medium. A related series of similar Penicillium isolates were isolated from air and soil, but these were less halo- and psychrotolerant. These two groups of Penicillia were shown to be closely related, both concerning their phenotypes and their phylogenetic placement and appeared to be new species. The new taxa had some resemblance to Penicillium section Brevicompacta including P. brevicompactum, P. bialowiezense (= P. biourgeianum), P. olsonii, Penicillium astrolabium and Penicillium neocrassum (Frisvad & Samson, 2004; Peterson, 2004; Serra & Peterson, 2007) but also to Penicillium section Ramosa (Stolk & Samson, 1985; Houbraken & Samson, 2011). The two new taxa are described here using a polyphasic taxonomic approach using molecular data (RPB2, ITS, partial β-tubulin and calmodulin sequences), morphology, phenotypic cultural characters, physiological features and extrolite profiles.