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Summary: The secretomes of filamentous fungi contain a diversity of small secreted cysteine‐rich proteins (SSCPs) that have a variety of properties ranging from toxicity to surface activity. Some SSCPs are recognized by other organisms as indicators of fungal presence, but their function in fungi is not fully understood. We detected a new family of fungal surface‐active SSCPs (saSSCPs), here named hyphosphere proteins (HFSs). An evolutionary analysis of the HFSs in Pezizomycotina revealed a unique pattern of eight single cysteine residues (C‐CXXXC‐C‐C‐C‐C‐C) and a long evolutionary history of multiple gene duplications and ancient interfungal lateral gene transfers, suggesting their functional significance for fungi with different lifestyles. Interestingly, recombinantly produced saSSCPs from three families (HFSs, hydrophobins and cerato‐platanins) showed convergent surface‐modulating activity on glass and on poly(ethylene‐terephthalate), transforming their surfaces to a moderately hydrophilic state, which significantly favoured subsequent hyphal attachment. The addition of purified saSSCPs to the tomato rhizosphere had mixed effects on hyphal attachment to roots, while all tested saSSCPs had an adverse effect on plant growth in vitro. We propose that the exceptionally high diversity of saSSCPs in Trichoderma and other fungi evolved to efficiently condition various surfaces in the hyphosphere to a fungal‐beneficial state. [ABSTRACT FROM AUTHOR]

Summary: Rhizobacteria devote a relatively large percentage of their genomes to encode bioactive natural products that are important for competition in the rhizosphere. In this study, a plant beneficial rhizobacterium Bacillus velezensis SQR9 was discovered to produce novel antibacterial fatty acids, Bacillunoic acids, which are encoded on a genomic island (GI). This GI contains a hybrid type I fatty acid synthase (FAS)‐polyketide synthase (PKS) system and an ABC transporter. The FAS was predicted to synthesize a primer that was transferred to the PKS to synthesize Bacillunoic acids. The synthesized Bacillunoic acids inhibit the growth of diverse bacteria, with the strongest activity against closely related Bacillus strains, the ABC transporter exported the toxic Bacillunoic acids upon their induction for protecting the producing strain. The inhibition of other Bacillus strains by Bacillunoic acids extended the antimicrobial spectrum of SQR9 and enhanced its competition with closely related root‐associated bacteria. So, through the obtaining of this GI by horizontal gene transfer, strain SQR9 not only acquired a competitive weapon but also acquired a self‐protecting shield, which increased its competition with other rhizobacteria. [ABSTRACT FROM AUTHOR]