IntroductionMorels (Morchella spp.) are popular and high-value edible ascomycetes composed of over 40 species that display a wide distribution throughout the northern hemisphere (O’Donnell et al., 2011). Investigations utilizing advances in molecular species recognition techniques have shown that morel species are geographically distinct which suggests that morels are not successful at colonizing new niche environments (O’Donnell et al., 2011). The limited research that has been conducted to identify morels from cultivated landscape settings indicates that this ecological niche is dominated exclusively by two species: M. importuna and M. rufobrunnea (Kuo et al., 2012; Mann and Mann, 2014). Most species of morels are described as having smooth spores, but studies by Malloch (1973) and Paraguey-Leduc et al (1998) suggest that striately ornamented ascospores are a common feature in morels. The purpose of this project was 1) characterize the spore ornamentation of landscape morels from the Pacific Northwest (PNW), and 2) test the hypothesis of niche restriction for morel species by determining the identity of landscape morels in the PNW.

Multiple phylogenetic species of morels (Morchella) occur in landscape settings in the Pacific Northwest

McCotter, S.W., Aujla, I.S., Garfinkel, A.R., Jardini, T.M., Mullahy, S., Xia, C., Adams, M., Carris, L.M., & Peever, T.L.Advanced Fungal Biology Class, Department of Plant Pathology, Washington State University, Pullman

Results• Landscape specimens represented 5 distinct species (Fig. 1), including 3 previously

reported from non-landscape settings• All ascospores examined with LM and SEM were striate or wrinkled in

ornamentation (Fig. 1)

MethodsMorels were collected in spring from suburban landscapes (Table 1). Isolates were grown on PDA amended with streptomycin-penicillin covered by dialysis membranes. DNA was extracted from lyophilized mycelium using a modified phenol-chloroform protocol (Pagliaccia et al., 2011). EF-1α, RPB1, RPB2 and nLSU rDNA were PCR-amplified and Sanger-sequenced in both directions using primers from O’Donnell et al. (2011). The alignments for each locus were concatenated. jModelTest 2.1.4 was used to identify the TrNef+I model of nucleotide substitution. MrBayes 3.2.2 and GARLI 0.96 were used for Bayesian and maximum likelihood phylogenetic inference, respectively. Ascospores were prepared using critical point drying for Scanning electron microscopy (SEM) and mounted in lactic acid for light microscopy (LM).

Isolate Code Collection Location Collection

Year

1 Bark bed – Pullman, WA 2013

2 Landscape – Moscow, ID 2011

3 Landscape rock – Salt Spring Island, BC 2013

4 Landscape rock – Salt Spring Island, BC 2013

5 Landscape rock – Salt Spring Island, BC 2013

6 Bark bed – Pullman, WA 2013

7 Bark bed – Pullman, WA 2013

8 Bark bed – Pullman, WA 2013

9 Lawn – Pullman, WA 2011

10 Bark bed – Pullman, WA 2013

11 Lawn – Pullman, WA 2011

SummaryWe found that the 11 morels collected from landscape settings at 9 sites in the PNW represent five distinct species of morels (Fig. 1). Most of the specimens were M. importuna, but we also identified three lineages previously unreported in landscape settings: M. brunnea, M. populiphila, and M. snyderi. These three species have only been reported from forests and other undisturbed habitats (Kuo et al., 2012), demonstrating that there is overlap in ecological niches among different species of morels. The fifth lineage we identified is Mel-8 (O’Donnell et al. 2011), a lineage that has only been identified once from a backyard in Northern California (Kuo et al. 2012). Our Mel-8 specimen is the first with a mature ascocarp and ascospores. Ascospore ornamentation is striate or wrinkled in the 4 species we examined (Fig. 1). The ornamentation is visible with both LM and SEM (Fig. 1), suggesting that spore ornamentation is not an artifact of SEM. Our results showing spore ornamentation is consistent with previous studies by Malloch (1973) and Paraguey-Leduc et al. (1998). Additionally, three species of morels have been described with ornamented spores (Chen and Liu, 2005; Elliot et al., 2014; Isiloglu et al., 2010). These results suggest that ascospore ornamentation is a common feature in Morchella.

References: Chen, J-Y and P-G Liu. 2005. Mycotaxon 93: 89-93. Elliot et al. 2014. Mycologia 106: 113-118. Isiloglu et al. 2010. Mycologia 102: 455-458. Kuo et al. 2012. Mycologia 104(5): 1159-1177. Mann, H. and P. Mann. 2014. Omphalina 5(2): 11-12. Malloch, D. 1973. Can. J. Bot. 51: 1519-1520. O’Donnell et al. 2011. Fungal Genetics and Biology 48: 252-265. Pagliaccia et al. 2011. Mycologia 103: 969-982. Parguey-Leduc et al. 1998. Cryptogamie, Bryol. Lichenol. 19 (2-3): 277-292.

Table 1. Specimens used in study with collection locations and collection year.

Fig. 1. Cladogram showing the identity of landscape morels (colored boxes); images of ascocarps, and ascospores (SEM and LM) shown at right. Bolded lines represent bootstrap values and posterior probabilities greater than 70.