In Vitro Interactions between Eutypella parasitica and Some Frequently Isolated Fungi from the Wood of the Dead Branches of Young Sycamore Maple (Acer pseudoplatanus)

Abstract

The ten most frequently isolated fungi from the wood of the dead branches of Acer pseudoplatanus L. were tested in dual cultures to evaluate their in vitro antagonistic activity against Eutypella parasitica R.W. Davidson and R.C. Lorenz, the causative agent of a destructive disease of maples in Europe and North America. The tested fungi, treated also as challenge isolates, were Diaporthe sp., Eutypa sp., Eu. maura, E. parasitica, Fusarium avenaceum, Neocucurbitaria acerina, Neonectria sp., Peniophora incarnata, Petrakia irregularis, and Phomopsis pustulata. The antagonistic ability of each challenge isolate was evaluated by calculating an index of antagonism (AI) based on the interaction type in the dual cultures. The results of competition between the fungal isolates were quantified after re-isolations from the interaction zone (s). The dual cultures revealed two main types of competitive interactions: Deadlock, consisting of mutual inhibition after mycelial contact or at a distance, and replacement, reflecting in the inhibition of E. parasitica, followed by partial overgrowth by the replacing fungus. Statistical analysis showed significant differences in average AI and s of challenge isolates between different dual culture assays. Based on the results of the antagonism index, Eutypa sp., Eu. maura, Neonectria sp., and P. incarnata had the highest inhibitory effect on E. parasitica growth and were recognized as the most promising candidates for further biocontrol studies of E. parasitica. The mycelium of E. parasitica at the interaction zones remained mostly viable, except in dual cultures with Eutypa sp., F. avenaceum, and Neonectria sp., where re-isolations did not yield any colony of the E. parasitica isolate. Based on the results, we assume that E. parasitica is a weak competitor, which invests less energy in direct mycelial competition. We discuss the potential of the observed antagonists as a possible biocontrol of Eutypella canker of maple. Nevertheless, additional experiments should be performed for a solid conclusion about competitive ability of E. parasitica and usefulness of antagonists as biocontrol.

New Potential Biological Limiters of the Main Esca-Associated Fungi in Grapevine

“…In the other combinations, the pathogenic organism was replaced by the biological limiter. The outcomes of these experiments allowed us to assume the weak competitive capacity of FM, PM, and PC, as hypothesized for Scleroconidioma sphagnicola [ 45 ] and Eutypella parasitica [ 46 ]. A similar re-isolation result after deadlock at a distance (interaction type B) was reported by Koukol et al [ 45 ], which was not recorded in our study.…”

“…The estimated value of s ranges between +1.79 and −1.79. Higher values of s indicate greater re-isolation success [ 45 , 46 ].…”

Terpenoids and other secondary metabolites produced by the Eutypella fungi and their bioactivities

“…Eutypella are cosmopolite and diverse fungi, which are included in phylum Diatrypaceae, subclass Xylariomycetidae, and genus Eutypella (Acero et al, 2017). They are commonly isolated from various terrestrial and marine environments (Da Silva et al, 2008;Moyo et al, 2016;Zhang, 2019) and play an important ecological role as a decomposer (Lee et al, 2011;Deng et al, 2019;Brglez et al, 2020). Meanwhile, the fungi Eutypella are reported to be valuable biological resources due to their ability to produce bioactive secondary metabolites such as terpenoids, alkaloids, and polyketides (Sun et al, 2011;Liu et al, 2014b;Niu et al, 2017a;Zhang et al, 2020;Zhang et al, 2021b).…”

The Biodiversity of Microfungi Isolated from the Bark of the Sugar Maple (Acer saccharum)

“…N. acerina has only been reported from Europe, where it commonly grows on wood and bark of Acer campestre and A. pseudoplatanus. , Brglez et al 2020). This study suggests that North American maples species such as A.…”