A biosynthetic gene cluster that is significantly upregulated in the fungal wheat pathogen Parastagonospora nodorum during plant infection was reconstructed heterologously in Aspergillus nidulans. This led to the discovery of five new α-pyrone polyketides, alternapyrones B-F (2-6). Compounds 5 and 6, which contain a highly substituted dihydrofuran, exhibited phytotoxicity on wheat seed germination. It is demonstrated that only three enzymes, one highly reducing polyketide synthase and two multifunctional P450 oxygenases, are needed to synthesize the structurally complex products.

actin polymerization was assessed using the Actin Polymerization Biochem assay (Cytoskeleton Inc, Denver, CO). Further experimental details of the biologial assays are provided in Supporting Information.

The aldol reaction is one of the most fundamental stereocontrolled carbon–carbon bond‐forming reactions and is mainly catalyzed by aldolases in nature. Despite the fact that the aldol reaction has been widely proposed to be involved in fungal secondary metabolite biosynthesis, a dedicated aldolase that catalyzes stereoselective aldol reactions has only rarely been reported in fungi. Herein, we activated a cryptic polyketide biosynthetic gene cluster that was upregulated in the fungal wheat pathogen Parastagonospora nodorum during plant infection; this resulted in the production of the phytotoxic stemphyloxin II (1). Through heterologous reconstruction of the biosynthetic pathway and in vitro assay by using cell‐free lysate from Aspergillus nidulans, we demonstrated that a berberine bridge enzyme (BBE)‐like protein SthB catalyzes an intramolecular aldol reaction to establish the bridged tricyclo[6.2.2.02,7]dodecane skeleton in the post‐assembly tailoring step. The characterization of SthB as an aldolase enriches the catalytic toolbox of classic reactions and the functional diversities of the BBE superfamily of enzymes.

Stellera chamaejasme L. is the most problematic weed in China’s grasslands. Its root exudates affect co-occurring plants and thus may also affect soil fungi. Soils (0–20 cm depth) on two adjacent sites, one invaded the other uninvaded, were compared for a range of physiochemical parameters and by DNA sequencing of fungal communities. At the invaded site, relationships between S. chamaejasme abundance, soil physiochemical factors, and fungal communities were further investigated to determine whether these relationships corroborated conclusions on the basis of site differences that could be translated into functional variation. Results showed that the invaded soils had lower N, P, organic matter, fungal alpha diversity, and relative abundance of arbuscular mycorrhizal fungi (AMF), but greater abundance of pathogenic fungi. Organic matter and P were the edaphic factors most strongly linked to site differences in total fungal communities. Within the invaded site, organic matter rather than S. chamaejasme cover was closely linked to total fungal composition. However, on this site, a number of fungal species that had various ecological functions and that differentiated the two sites were related to S. chamaejasme cover. This study indicates that lower fertility soils may be more susceptible to invasion by S. chamaejasme. Although the influence of S. chamaejasme on total fungal community composition was limited, there was evidence of effects on particular fungal species. Further research is needed to determine whether these effects influence S. chamaejasme invasiveness.

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