Biocontrol of Phytophthora xcambivora on Castanea sativa: Selection of Local Trichoderma spp. Isolates for the Management of Ink Disease

Abstract

Ink disease is a devastating disease of chestnut (Castanea sativa) worldwide, caused by Phytophthora species. The only management measures of this disease are chemical and agronomic interventions. This work focuses on the evaluation of the in vitro antagonistic capacity of 20 isolates of Trichoderma spp. selected in a diseased chestnut orchard in Tuscan Apennines (San Godenzo, Italy) for the biocontrol of Phytophthora xcambivora. Each Trichoderma isolate was tested to investigate pathogen inhibition capability by antagonism in dual cultures and antibiosis by secondary metabolites production (diffusible and Volatile Organic Compounds). The six most performing isolates of Trichoderma spp. were further assessed for their aptitude to synthesize chitinase, glucanase and cellulase, and to act as mycoparasite. All six selected isolates displayed the capability to control the pathogen in vitro by synergistically coupling antibiosis and mycoparasitism at different levels regardless of the species they belong to, but rather, in relation to specific features of the single genotypes. In particular, T. hamatum SG18 and T. koningiopsis SG6 displayed the most promising results in pathogen inhibition, thus further investigations are needed to confirm their in vivo efficacy.

Heritage grapevines as sources of biological control agents for Botryosphaeria dieback pathogens

“…This ability has been extensively reported. For example, T. asperellum UDEAGIEM-H01 formed coils around hyphae of F. oxysporum and Macrophomina phaseolina (Díaz-Gutiérrez et al, 2021), T. harzianum KMISO2-2-19A around Fusarium virguliforme hyphae (Pimentel et al, 2020), and T. koningiopsis around hyphe of Phytophthora xcambivora (Frascella et al, 2022). Coiling around hyphae is the first step of Trichoderma mycoparasitic activity, and is followed by production of hydrolytic enzymes that allow Trichoderma to penetrate the hosts and absorb their contents (Rocha-Ramirez et al, 2002).…”

Exploring the antagonist potential of indigenous Trichoderma spp., Bacillus, and Pseudomonas against Phytophthora palmivora of Soe mandarin in East Nusa Tenggara, Indonesia

“…functions as a biocontrol agent by applying four distinctive methods to impede pathogens' growth. These methods include competing for food in the shared growth environment, utilizing antibiosis to release toxic biochemichal compounds to suppress pathogens, employing mycoparasitism by attaching to and binding with pathogenic fungal hyphae, and penetrating pathogenic fungal hyphae while synthesizing cell wall-degrading enzymes [13,14].…”

Characterization of Trichoderma species from forest ecosystems by high-throughput phenotypic microarray

“…Trichoderma isolates analyzed in this study were sampled as described in Venice et al (2021) (Venice et al, 2021) and selected against the target pathogens according to Frascella et al (2022) (Frascella et al, 2022). Briefly, soil samples were collected under the canopies of asymptomatic chestnut and silver fir trees, 1-3 m away from the trunk and 15-20 cm deep, and located close to the core of plants affected by ink disease and root rot, respectively.…”

“…The selection of the most performing Trichoderma isolates was carried out assessing the strategies implemented as antagonist against the target pathogens in vitro (Frascella et al, 2022). In detail, the ability of Trichoderma to form coilings around the pathogen's hyphae (mycoparasitism) was explored by microscope observations (light and SEM).…”

“…Six strains have been isolated in a mature chestnut orchard for fruit production (Castanea sativa Mill.) affected by ink disease and located in the Tuscan Apennines in San Godenzo (Florence, Italy) and showed a promising aptitude in the control (antagonistic activity) of Phytophthora xcambivora (Petri) Buisman (Frascella et al, 2022). Likewise, four strains have been isolated from a coetaneous mature silver fir stand (Abies alba Mill.)…”