Mevalocidin: A Novel, Phloem Mobile Phytotoxin from Fusarium DA056446 and Rosellinia DA092917

Abstract

A multiyear effort to identify new natural products was built on a hypothesis that both phytotoxins from plant pathogens and antimicrobial compounds might demonstrate herbicidal activity. The discovery of one such compound, mevalocidin, is described in the current report. Mevalocidin was discovered from static cultures of two unrelated fungal isolates designated Rosellinia DA092917 and Fusarium DA056446. The chemical structure was confirmed by independent synthesis. Mevalocidin demonstrated broad spectrum post-emergence activity on grasses and broadleaves and produced a unique set of visual symptoms on treated plants suggesting a novel mode of action. Mevalocidin was rapidly absorbed in a representative grass and broadleaf plant. Translocation occurred from the treated leaf to other plant parts including roots confirming phloem as well as xylem mobility. By 24 hr after application, over 20 % had been redistributed through-out the plant. Mevalocidin is a unique phytotoxin based on its chemistry, with the uncommon attribute of demonstrating both xylem and phloem mobility in grass and broadleaf plants.

Natural products: a strategic lead generation approach in crop protection discovery

“…Conventional biology has assumed that biodiversity is distributed unevenly, with an abundance of observable species in tropical and marine environments and in natural, as opposed to urban, landscapes. To sample diversity for NP discovery, approximately 90% of the inputs to the DAS NP program over the past 30 years were the result of collaborations with more than 50 private, academic and governmental entities . This third‐party sourcing enabled sampling of biodiversity from a wide range of geographic, environmental and taxonomic sources.…”

“…The fractions are re‐assessed for unique structural features, subsequently purified, and tested for bioactivity . At CAS, the focus on a bioactivity‐based tactic has proven fruitful, albeit lengthy, in identifying agrochemically relevant NPs of interest . The specific workflow and screening cascade utilized currently is illustrated in Fig.…”

“…). In the course of screening a large collection of fungal extracts from Mycosynthetix, mevalocidin was discovered at DAS from static cultures of two fungal isolates of Coniolariella spp. MSX92917 (DA092917) and MSX56446 (DA056446) .…”

“…MSX92917 (DA092917) and MSX56446 (DA056446) . Mevalocidin demonstrated broad‐spectrum post‐emergence activity on grasses and broadleaves . Symptoms of plants treated with mevalocidin suggest a novel MoA and ambi‐mobility in grass as well as in broadleaf weeds.…”

“…academic and governmental entities. [39][40][41][42][43][44] This third-party sourcing enabled sampling of biodiversity from a wide range of geographic, environmental and taxonomic sources. Third-party sources for DAS NP discovery over the past 25 years included more than 850 000 NP extracts and more than 2500 pure NPs.…”