Asymptomatic weeds are frequently colonised by pathogenic species of Fusarium in cereal‐based crop rotations

Abstract

Summary Several Fusarium species cause harmful cereal diseases, such as fusarium head blight and crown rot, which, during pathogenesis, may result in significant grain yield and quality losses. Several species of agricultural weed are believed to be alternative and reservoir hosts for Fusarium spp.; however, studies have not comprehensively evaluated those weed species in cropping systems that may harbour these fungi. The objective of this study was to determine weed species in cereal‐based crop rotations that are asymptomatically colonised by Fusarium spp. We sampled all species of weed present in fields that were managed under six different crop sequences in 2015 and 2016. The study yielded 2326 single‐spore isolates of Fusarium spp. derived from various organs of asymptomatic weeds. Isolates were identified morphologically and then confirmed using PCR with species‐specific primers and/or sequencing of tef1α gene fragments. Isolates of nine Fusarium spp. were obtained from 689 of the 744 individuals collected that represented 56 weed species. Each weed species harboured at least one species of Fusarium, and >80% were colonised by 3–9 Fusarium spp. In total, we identified 27 dicotyledonous weed species that were previously undocumented as Fusarium hosts and 251 new weed × Fusarium species combinations were revealed. Consequently, there is a greater risk of negative Fusarium impacts on cereal crops than was previously thought. We suggest effective weed management and inversion soil tillage may help mitigate these impacts.

Arable Weeds at the Edges of Kettle Holes as Overwintering Habitat for Phytopathogenic Fungi

“…Moreover, many different weed species have been identified as non-crop hosts for Fusarium spp. [10,21,22,[47][48][49][50] and thus can be taken into consideration as an overwintering habitat and source of infection for the next season's crop.…”

“…Most of them were detected as asymptomatic carriers of Fusarium diseases because they rarely show any visible symptoms of infection. Thus, weeds have the potential to act as reservoirs for fungi, thereby increasing the hazard of an infection of the crops growing simultaneously in the field [10,[19][20][21][22]. However, the importance of weeds in the Fusarium head blight disease cycle is not fully understood [21].…”

“…The diversity of plants at the edges of kettle holes offers different living conditions and microhabitats, such that a wide variety of fungi can find their special structural niche. For example, Suproniene et al [21,22] detected that many arable weeds are alternative and asymptomatic hosts for fungi of the genera Fusarium. Non-crop hosts such as Poa annua L., Viola arvensis L., and Galium aparine L. were frequently and strongly infected by different Fusarium species that rarely caused any visible symptoms.…”

Identification and pathogenicity of Fusarium spp. associated with tuber dry rot and wilt of potato in Algeria

“…Fusarium spp. were recovered from over 92% of sampled weed plants (Suproniene et al 2019). In such a way, fungi can survive in an area and infect the crop, when a suitable host species is sown.…”

An endophytic Fusarium–legume association is partially dependent on the common symbiotic signalling pathway

“…Focusing on plant–microbe co‐evolution, mechanisms that maintain variation for partner quality, a feature essential for the stabilization of symbiosis in evolutionary terms, are not clearly presented as yet, but it is clear that a dynamic frame of interactions is set (Heath & Stinchcombe, ). For example, different plant genotypes may host and respond to the same fungal strain differently, leading either in pathogenicity or benefit (Lofgren et al , ; Nieva et al , ; Suproniene et al , ). FsK is capable of achieving entry in the plant, either by use of the CSSP or by an alternative bypass pathway, which still allows for a less‐successful accommodation of FsK as a beneficial (or at least not harmful) endophyte.…”