Agrobacterium rhizogenes-mediated transformation of a high oil-producing fil a m en to us fungusUmbelopsis isabellina

A silver bullet in a golden age of functional genomics: the impact of Agrobacterium-mediated transformation of fungi

The implementation of Agrobacterium tumefaciens as a transformation tool revolutionized approaches to discover and understand gene functions in a large number of fungal species. A. tumefaciens mediated transformation (AtMT) is one of the most transformative technologies for research on fungi developed in the last 20 years, a development arguably only surpassed by the impact of genomics. AtMT has been widely applied in forward genetics, whereby generation of strain libraries using random T-DNA insertional mutagenesis, combined with phenotypic screening, has enabled the genetic basis of many processes to be elucidated. Alternatively, AtMT has been fundamental for reverse genetics, where mutant isolates are generated with targeted gene deletions or disruptions, enabling gene functional roles to be determined. When combined with concomitant advances in genomics, both forward and reverse approaches using AtMT have enabled complex fungal phenotypes to be dissected at the molecular and genetic level. Additionally, in several cases AtMT has paved the way for the development of new species to act as models for specific areas of fungal biology, particularly in plant pathogenic ascomycetes and in a number of basidiomycete species. Despite its impact, the implementation of AtMT has been uneven in the fungi. This review provides insight into the dynamics of expansion of new research tools into a large research community and across multiple organisms. As such, AtMT in the fungi, beyond the demonstrated and continuing power for gene discovery and as a facile transformation tool, provides a model to understand how other technologies that are just being pioneered, e.g. CRISPR/Cas, may play roles in fungi and other eukaryotic species.

Candida parapsilosis produces prostaglandins from exogenous arachidonic acid and OLE2 is not required for their synthesis

Prostaglandins are C20 fatty acid metabolites with diverse biological functions. In mammalian cells, prostaglandins are produced from arachidonic acid (AA) via cyclooxygenases (COX1 and COX2). Although fungi do not possess cyclooxygenase homologues, several pathogenic species are able to produce prostaglandins from host-derived arachidonic acid. In this study, we characterized the prostaglandin profile of the emerging human pathogen Candida parapsilosis with HPLC-MS and compared it to that of C. albicans. We found that both species synthesized prostaglandins (mainly PGD2 and PGE2) from exogenous AA. Furthermore, as OLE2 has been associated with prostaglandin synthesis in C. albicans, we generated homozygous OLE2 deletion mutants in C. parapsilosis and examined their PGE2 production. However, the PGE2 production of the OLE2 KO strain was similar to that of wild type (WT), indicating that OLE2 is not required for prostaglandin synthesis in C. parapsilosis. Interestingly, analyses of the fatty acid composition of WT and OLE2 KO cells by gas chromatography (GC) highlighted the accumulation of palmitoleic and oleic acid in the OLE2 deletion mutant. The OLE2 KO cells were killed more efficiently by human monocytes-derived macrophages (MDMs) as well as induced higher interleukin-10 (IL-10) secretion, indicating that OLE2 affects the virulence of C. parapsilosis. Taken together, these results contribute to the better understanding of fatty acid biosynthesis pathways in C. parapsilosis.