Ampelomyces mycoparasites of powdery mildews – a review

This review paper highlights the significant research conducted on fungi belonging to the genus Ampelomyces. Phylogeny based on both ITS and actin sequences has grouped Ampelomyces into different lineages. However, the ITS2 spacer, one constituent of the ITS region, together with their secondary structures (S2s), showed that these lineages are represented by different S2s; also, evidence of pseudogene formation in nuclear ribosomal genes of two isolates was reported, and S2s in Ampelomyces mycoparasites are different from those in Phoma-like fungi. Ampelomyces taxonomy is unresolved and future multi-locus analysis will assist in delimiting species. Members of the genus Ampelomyces are among the first mycoparasites used to control powdery mildew fungi as they can efficiently eliminate mycelial growth and reduce the overwintering inoculum of their mycohosts. In addition, Ampelomyces isolates were found to be resistant to some fungicides and insecticides, e.g. pyrazophos, an attractive feature for their selection as biocontrol agents. Transcriptome analyses have revealed that expression of the genes that encode proteins putatively associated with virulence and plant immune responses were enhanced during host recognition, while genes-encoding proteins linked to antibiotic resistance were predicted within the Ampelomyces genome. Proteomic studies are needed to confirm whether these proteins function in virulence and can therefore be used for biocontrol purposes or as bacterial antibiotic-resistant proteins, and which of these may trigger plant immune responses to facilitate plant protection. We encourage the continuation of these studies to benefit crop protection research.