Effects of Lactarius deliciosus and Rhizopogon roseolus ectomycorrhyzal fungi on seeds and seedlings of Scots and stone pines inoculated with Fusarium oxysporum and Fusarium verticillioides

Abstract

Two isolates of the edible ectomycorrhizal fungi (ECM), Lactarius deliciosus and Rhizopogon roseolus, were tested against Fusarium oxysporum and F. verticillioides, causal agents of damping-off on seeds and seedlings of Scots pine (Pinus sylvestris) and stone pine (Pinus pinea). The effects of ECM on Fusarium spp. in the rhizosphere of Scots and stone pines were evaluated by: (1) co-inoculating ECM and Fusarium when seeding (seed test) and (2) co-inoculating eight-week-old seedlings (seedling test). The seed tests showed significant reduction of Scots pine seed germination when treated with F. verticillioides, but this effect was absent when co-inoculated with R. roseolus. Higher germination rates were observed in stone pine when F. oxysporum was co-inoculated with L. deliciosus than the pathogen inoculation alone. In the seedling test, Scots and stone pines were not apparently affected by Fusarium spp. No obvious changes in plant growth-related variables were observed in either assay. Root colonization of Scots and stone pine seedlings by R. roseolus was 15.5% and 12% for the seed assay, as well as 21.6% and 11% for the seedling assay. Lactarius deliciosus mycorrhizal roots were found only in Scots pine seedlings (10%). Rhizopogon roseolus and L. deliciosus are two promising fungi for pine seedling protection against Fusarium damping-off at nurseries.Keywords: biological control, ectomycorrhizal fungi, nursery diseases, Pinus sylvestris, Pinus pinea. RÉSUMÉOn a testé deux isolats des champignons ectomycorhiziens comestibles (ECM) Lactarius deliciosus et Rhizopogon roseolus pour lutter contre Fusarium oxysporum et F. verticillioides, qui provoquent la fonte des graines et des semis chez le pin sylvestre (Pinus sylvestris) et le pin parasol (Pinus pinea). L' expérience consistait à évaluer l' effet de l'ECM dans la rhizosphère des pins sylvestre et parasol en (1) inoculant à la fois l'ECM et Fusarium au moment de l' ensemencement (essai sur les semences) et (2) en les inoculant aussi à des semis âgés de huit semaines (essai sur des semis). Les essais sur les semences ont montré une réduction significative de la germination chez les semences de pin sylvestre traitées avec F. verticillioides, mais cet effet disparaissait lorsqu' on inoculait aussi R. roseolus aux semences. On a aussi obtenu un taux de germination plus élevé chez le pin parasol en inoculant à la fois F. Oxysporum et L. deliciosus qu' en n'inoculant que le pathogène. Dans l' essai sur les semis, le pin sylvestre et le pin parasol n' ont pas semblé affectés par Fusarium spp. On n'a pas observé non plus d' effet sur les paramètres de croissance de la plante dans les deux essais. Dans l' essai sur les semences, le pourcentage de colonisation des racines par R. Roseolus a atteint 15,5 % chez le pin sylvestre et 12 % chez le parasol ainsi que 21,6 % et 11 % respectivement dans l' essai sur les semis. Seules les racines du pin sylvestre ont été colonisées par Lactarius deliciosus (10 %). Rhizopogon roseolus et L. deliciosus sont deux champignons pr...

Epiphytic and Endophytic Fungi Colonizing Seeds of Two Poaceae Weed Species and Fusarium spp. Seed Degradation Potential In Vitro

“…For example, seeds of Pseudotsuga menziesii were shown to carry numerous Fusarium species that mostly caused no disease of either seeds or plants [ 13 ]. At the same time, F. oxysporum significantly reduced the germination of Pinus sylvestris and P. pinea , while F. verticillioides ( F. fujikuroi ) only reduced the germination of P. sylvestris [ 14 ]. The genus Fusarium includes species and strains that are pathogenic to seeds of different species of Poaceae .…”

Using Microorganismal Consortium and Bioactive Substances to Treat Seeds of Two Scots Pine Ecotypes as a Technique to Increase Re-Afforestation Efficiency on Chalk Outcrops

“…A cutting-edge research trend is to study the impact of biopreparations on Pinus species' capacity for survival and establishment [43][44][45].…”

Soil mycobiome in sustainable agriculture

“…Few studies have documented the microbial changes that occur after the emergence of a plant pathogen, especially in forest ecosystems ( Stewart et al, 2021 ). Some species (e.g., Laccaria laccata , Hebeloma crustuliniforme , Paxillus involutus , Trichoderma harzianum , Pisolithus tinctorius , Tricholoma pessundatum ) have been shown to play an essential role in decreasing the severity of disease caused by root pathogens ( Chakravarty and Hwang, 1991 ; Suárez et al, 2018 ; Stewart et al, 2021 ; Zaki et al, 2021 ). However, some fungal pathogens can deactivate genes in non-pathogenic species; they are involved in antimicrobial production and further weaken tree symbionts by releasing secondary metabolites ( Stewart et al, 2021 ).…”