Abstract
Soil-borne fungal diseases are a major problem in agriculture. A century ago, the Dutch plant pathologist Johanna Westerdijk recognized the importance of linking fungal biology with ecology to understand plant disease dynamics. To explore new ways to manage soil-borne fungal disease in agriculture by ‘learning from nature’, we follow in her footsteps: we link below ground plant-fungal pathogen interactions to ecological settings, i.e. natural grasslands. Ecological research hypothesised that the build-up of ‘enemies’ is reduced in species-rich vegetation compared to monocultures. To understand how plant diversity can suppress soil-borne fungal pathogens, we first need to identify fungal actors in species-rich grasslands. Next-generation sequencing revealed a first glimpse of the potential fungal actors, but their ecological functions often remain elusive. Databases are becoming available to predict the ecological fungal guild, but classic phytopathology studies that isolate and characterize – taxonomically and functionally -, remain essential. Secondly, we need to set-up experiments that reveal ecological mechanisms underlying the complex below ground interactions between plant diversity and fungal pathogens. Several studies suggested that disease incidence of (host-specific) pathogens is related to abundance of the host plant species. However, recent studies suggest that next to host species density, presence of heterospecific species additionally affects disease dynamics. We explore the direct and indirect ways of these neighboring plants diluting pathogen pressure. We argue that combining the expertise of plant pathologists and ecologists will improve our understanding of belowground plant-fungal pathogen interactions in natural grasslands and contribute to the design of sustainable and productive intercropping strategies in agriculture.
Highlights
Termorshuizen Aad Termorshuizen Consultancy, Kabeljauwallee 11, 6865 BL Doorwerth, The Netherlands. In her search for the causal agent of the disease that caused major die-back of Elm trees, Johanna Westerdijk did not just focus on the interaction between the pathogenic fungus and the tree alone. She and her team studied the ecology of the European elm bark beetle (Scolytus multistriatus), which acted as the vector of the fungal pathogen Graphium ulmi ( Ophiostoma ulmi) on elm trees
Westerdijk recognized the important role of complex species interactions in explaining plant disease dynamics
There is interest in the role of fungal pathogens to explain the maintenance of biodiversity (Bever et al 2015; Gilbert 2002), but in this review we focus on the other way around: the role of plant species diversity to reduce the build-up of soilborne fungal disease (Latz et al 2012; Mommer et al 2018; Yang et al 2015)
Summary
In her search for the causal agent of the disease that caused major die-back of Elm trees, Johanna Westerdijk did not just focus on the interaction between the pathogenic fungus and the tree alone. Main agricultural soil-borne fungal diseases include Fusarium wilt (Fusarium oxysporum), Verticillium wilt (Verticillium dahliae) and damping-off diseases induced by e.g. Rhizoctonia solani and Pythium spp These are well-studied because of their widespread occurrence in many crops worldwide. On golf courses (turfgrass), grassland species, such as Poa pratensis and Festuca rubra, are known to suffer from several of the same soil-borne pathogens found in agricultural monocot crops (e.g. brown patch disease (R. solani), damping-off disease (Fusarium, Pythium, and Rhizoctonia spp.), and take-all disease (Gaeumannomyces graminis) (Smiley et al 2005). R. solani and Fusarium spp. were found in Plantago lanceolata (ribwort plantain) and Fusarium solani in Hypericum perforatum (St John’s Wort) commercial plantings (Gaetán et al 2004; Zimowska 2013) This evidence stems from forb species, these have been cropped as monocultures and such insights may, not directly be translated to plantpathogen associations in species-rich grasslands. These studies and others (see Table 1) show that the most commonly documented fungal pathogenic effect on the host plants under controlled conditions is a reduction in (total) biomass
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
