Remediation of Phytophthora ramorum-infested soil with Trichoderma asperellum isolate 04-22 under ornamental nursery conditions

Forest decline is nowadays a major challenge for ecosystem sustainability. Dehesas, which consists of savannah-like mediterranean ecosystems, are threatened by the holm oak decline in the south-west of Iberian peninsula. Phytophthora cinnamomi is considered the main agent of holm oak root rot, but little is known about the relationship between diversity of soilborne microbial community and the decline syndrome of holm oak. It would be hypothesized that the changes in the structure and functionality of the soil microbiome might influence tree health status through changes in richness and diversity of beneficial organisms such as mycorrhizal species, or fungal plant pathogens such as Fusarium spp. or Alternaria spp. total DNA of soil samples from declined oak dehesas was extracted and analyzed through metabarcoding techniques, to evaluate the specific composition and diversity of the fungal and oomycete communities and their relationship with the disease symptoms. the fungal community included a wide range of pathogens and abundance of ectomycorrhizal key taxa related with low defoliation degree. Phytophthora cinnamomi and Pythium spiculum did not appear among the most abundant oomycetes, nor were they related directly to defoliation levels. Moreover, a particular taxon belonging to the genus Trichoderma was strongly correlated with the scarcity of pathogenic Phytophthora spp. the diversity and composition of fungal and oomycete communities were related to the severity of the decline symptoms. the metabarcoding study of microbiome represents a powerful tool to develop biocontrol strategies for the management of the holm oak root rot.

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“…have also been proved to be antagonists of diverse Phytophthora spp. 81–85 . The evidence of the multiple effects of Trichoderma spp.…”

Section: Discussionmentioning

confidence: 99%

Assessment of functional and structural changes of soil fungal and oomycete communities in holm oak declined dehesas through metabarcoding analysis

Gómez

Navarro-Cerrillo

Pérez‐de‐Luque

et al. 2019

Sci Rep

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“…Despite some limitations in the experimental design, Widmer and Shishkoff (2017) also reported that the use of Ta 04-22 applied as wheat bran top-dressing reduced the P. ramorum inoculum, while the formulation of Ta 04-22 as a wettable powder and applied as root drench reduced the inoculum better than the commercial product Rootshield® Plus (T. harzianum Rifai strain T-22 and T. virens G-41) [27]. To further investigate the biological control effect of Ta 04-22 in field conditions, Widmer and colleagues [28] formulated the T. asperellum as wheat bran and as a wettable powder (Ta 04-22WP) in several final concentrations and tested it against soil artificially and naturally infected with P. ramorum, but with no plants. They reported that Ta 04-22, in both formulations and without the interference of seasons, reduced P. ramorum to non-detectable levels in the two trials.…”

Section: Eligibility Criteria Study Selection and Data Extraction And...mentioning

confidence: 99%

A systematic review about biological control of phytopathogenic Phytophthora cinnamomi

2022

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which represents a concerning economic problem, mainly in Portugal [2].The current management strategies for P. cinnamomi are limited due to the difficulty in diagnosis, as the plants remain symptomless until the late stages of the infection [3]. The prevention of soil flood and excessive moisture is a control strategy for this oomycete insofar as high soil moisture provides favorable conditions for P. cinnamomi to produce and increase the dispersal of zoospores [3,4]. The use of convenient irrigation and drainage techniques is used to avoid the growth of the soil-borne pathogen; however, they are effective only when the soil is not contaminated with zoospores. In this particular scenario, the soil needs to be cleaned with fumigation and other appropriate agrochemicals, to purge the P. cinnamomi [1,5]. Further management techniques include the use of seed treatments and resistant cultivars in zoospores-free soil and crop rotation. Whereas the first offers some flexibility to the producers, the last one is not widely used due to limitations of planting lands and the long-term survival of P. cinnamomi zoospores [6,7].The most commonly used management strategies for P. cinnamomi are phosphonate-based chemical fungicides (e.g. potassium phosphite) and phenylamide compounds (e.g. mefenoxam) [1,8]. Both of these fungicides are effective Altino Choupina

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“…To date, much research has confirmed the role of Trichoderma spp. In controlling or even reducing Phytophthorarelated diseases [21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Antagonistic Potential of Native Trichoderma spp. against Phytophthora cinnamomi in the Control of Holm Oak Decline in Dehesas Ecosystems

Ruíz-Gómez

Miguel-Rojas

2021

Forests

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Phytophthora root rot caused by the pathogen Phytophthora cinnamomi is one of the main causes of oak mortality in Mediterranean open woodlands, the so-called dehesas. Disease control is challenging; therefore, new alternative measures are needed. This study focused on searching for natural biocontrol agents with the aim of developing integrated pest management (IPM) strategies in dehesas as a part of adaptive forest management (AFM) strategies. Native Trichoderma spp. were selectively isolated from healthy trees growing in damaged areas by P. cinnamomi root rot, using Rose Bengal selective medium. All Trichoderma (n = 95) isolates were evaluated against P. cinnamomi by mycelial growth inhibition (MGI). Forty-three isolates presented an MGI higher than 60%. Twenty-one isolates belonging to the highest categories of MGI were molecularly identified as T. gamsii, T. viridarium, T. hamatum, T. olivascens, T. virens, T. paraviridescens, T. linzhiense, T. hirsutum, T. samuelsii, and T. harzianum. Amongst the identified strains, 10 outstanding Trichoderma isolates were tested for mycoparasitism, showing values on a scale ranging from 3 to 4. As far as we know, this is the first report referring to the antagonistic activity of native Trichoderma spp. over P. cinnamomi strains cohabiting in the same infected dehesas. The analysis of the tree health status and MGI suggest that the presence of Trichoderma spp. might diminish or even avoid the development of P. cinnamomi, protecting trees from the worst effects of P. cinnamomi root rot.

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Remediation of Phytophthora ramorum-infested soil with Trichoderma asperellum isolate 04-22 under ornamental nursery conditions

Cited by 11 publications

References 33 publications

Assessment of functional and structural changes of soil fungal and oomycete communities in holm oak declined dehesas through metabarcoding analysis

Assessment of functional and structural changes of soil fungal and oomycete communities in holm oak declined dehesas through metabarcoding analysis

A systematic review about biological control of phytopathogenic Phytophthora cinnamomi

Antagonistic Potential of Native Trichoderma spp. against Phytophthora cinnamomi in the Control of Holm Oak Decline in Dehesas Ecosystems

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