The hunt for sustainable biocontrol of oomycete plant pathogens, a case study of Phytophthora infestans

Hashemi, Maryam; Tabet, Dania; Sandroni, Murilo; Benavent-Celma, Clara; Seematti, Jenifer; Andersen, Christian B.; Grenville‐Briggs, Laura J.

doi:10.1016/j.fbr.2021.11.003

Cited by 31 publications

(27 citation statements)

References 97 publications

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“…Indeed, earlier studies have reported inhibition of P. infestans mycelial growth by different Streptomyces strains or their metabolites ( Sinha et al, 2014 ; Bermejo et al, 2020 ; Feng et al, 2021 ). However, in vitro inhibition activities on P. infestans are no warranty for the ability of the strains to restrict disease progress on plant material such as leaf discs or full plants, which in turn do not warrant efficacy in the field ( Guyer et al, 2015 ; Hashemi et al, 2021 ). To the best of our knowledge, only two studies reported protective potential of Actinomycetes against P. infestans in full plant assays, the first on tomato and chili ( Loliam et al, 2012 ), and the second on potato tubers ( Feng et al, 2022 ).…”

Section: Introductionmentioning

confidence: 99%

Evaluating the Antagonistic Potential of Actinomycete Strains Isolated From Sudan’s Soils Against Phytophthora infestans

et al. 2022

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Soil microorganisms play crucial roles in soil fertility, e.g., through decomposing organic matter, cycling nutrients or through beneficial interactions with plants. Actinomycetes are a major component of soil inhabitants; they are prolific producers of specialized metabolites, among which many antibiotics. Here we report the isolation and characterization of 175 Actinomycetes from rhizosphere and bulk soil samples collected in 18 locations in Sudan. We evaluated the strains’ metabolic potential for plant protection by testing their ability to inhibit the mycelial growth of the oomycete Phytophthora infestans, which is one of the most devastating plant pathogens worldwide. Most strains significantly reduced the oomycete’s growth in direct confrontational in vitro assays. A significant proportion of the tested strains (15%) were able to inhibit P. infestans to more than 80%, 23% to 50%–80%, while the remaining 62% had inhibition percentages lesser than 50%. Different morphologies of P. infestans mycelial growth and sporangia formation were observed upon co-inoculation with some of the Actinomycetes isolates, such as the production of fewer, thinner hyphae without sporangia leading to a faint growth morphology, or on the contrary, of clusters of thick-walled hyphae leading to a bushy, or “frozen” morphology. These morphologies were caused by strains differing in activity levels but phylogenetically closely related with each other. To evaluate whether the isolated Actinomycetes could also inhibit the pathogen’s growth in planta, the most active strains were tested for their ability to restrict disease progress in leaf disc and full plant assays. Five of the active strains showed highly significant protection of potato leaves against the pathogen in leaf disc assays, as well as substantial reduction of disease progress in full plants assays. Using cell-free filtrates instead of the bacterial spores also led to full protection against disease on leaf discs, which highlights the strong crop protective potential of the secreted metabolites that could be applied as leaf spray. This study demonstrates the strong anti-oomycete activity of soil- and rhizosphere-borne Actinomycetes and highlights their significant potential for the development of sustainable solutions based on either cell suspensions or cell-free filtrates to safeguard potatoes from their most damaging pathogen.

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Section: Introductionmentioning

confidence: 99%

Evaluating the Antagonistic Potential of Actinomycete Strains Isolated From Sudan’s Soils Against Phytophthora infestans

et al. 2022

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“…Other OGBa strains are currently approved for the control of fungal diseases of plants, in the EU namely Bacillus amyloliquefaciens QST713, AH2, IT45, MBI 600, FZB24 and D747, and Bacillus velezensis RTI301. These are the active ingredients in fungicides like SERENADE Max, TAEGRO, Kodiak and Double Nickel 55 [20,32]. In addition, we found several different M. pulcherrimia yeast strains (#118, #195, #196, #197, #332, #482 and #483) which were highly active against P. cinnamomi in vitro, and which might be interesting candidates for the development of a biocontrol agent.…”

Section: Discussionmentioning

confidence: 73%

Investigating the Biocontrol Potential of the Natural Bacterial Flora of the Apple Blossom

Schnyder¹,

Eberl²,

Agnoli³

2022

Preprint

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Erwinia amylovora, the causative agent of fire blight, leads to important economic losses of apple and pear crops worldwide. This study aimed to investigate the potential of the resident bacterial flora of the apple blossom in combatting plant disease-causing organisms, with a focus on strains that show potential for controlling fire blight. We collected samples of apple blossoms from dif-ferent sites around Canton Zurich, some grown with and some without the use of conventional pesticides, and isolated 538 strains which we tested for activity against Pectobacterium carotovorum and E. amylovora. We also tested the isolates against oomycete and fungal pathogens, to evaluate them for additional potential as biocontrol agents. Nine isolates showed activity against P. ca-rotovorum and eight of these against E. amylovora. Furthermore, 117 showed antifungal and 161 anti-oomycete activity. Five strains showed activity against all classes of pathogen and were tested in a detached apple model for anti-E. amylovora activity. Of these five strains, two were able to antagonise E. amylovora; Bacillus velezensis #124 and Pantoea agglomerans #378. We also show that B. velezensis #124 exhibits strong activity against three different fungi and two oomycetes in vitro, suggesting that this strain might have broad potential for biocontrol. Our results showcase the potential of the natural apple blossom flora. We isolated two candidate biocontrol strains from apple blossoms, suggesting that they can persist at the most common entry point for the causative agent of fire blight. Furthermore, they are probably already part of the human diet, suggesting they are safe for consumption and thus are promising candidates for biocontrol applications.

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“…Whilst pesticides are efficient at controlling this disease, they have certain drawbacks: an environmental and economic burden, food safety problems and human health threats, and the opportunity for drug-resistant strains to emerge [ 7 , 9 , 10 ]. Considering the threat to the environment, the EU has implemented directives on reducing the use of synthetic pesticides and increasing sustainable alternative disease control strategies [ 11 ]. As a result, there is an urgent need to develop alternative methods to reduce the use of pesticides.…”

Section: Introductionmentioning

confidence: 99%

“…Biological control, an alternative to pesticides, can be defined as the application of beneficial microorganisms to counteract plant pathogens, to reduce the symptoms of diseases [ 11 , 12 ]. Endophytes refer to microbes that colonize plant tissues or organs for part or all of their life cycles without causing adverse plant symptoms, including endophytic fungi, bacteria, and actinomyces [ 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Isolation and Screening of Antagonistic Endophytes against Phytophthora infestans and Preliminary Exploration on Anti-oomycete Mechanism of Bacillus velezensis 6-5

Zhang

Huang

Hou

et al. 2023

Plants

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Phytophthora infestans, the notorious pathogen of potato late blight, leads to a severe decline in potato yields and even harvest failure. We isolated 201 endophytic isolates from healthy root tissues of potatoes, among which 41 showed strong antagonistic activity against P. infestans. Further, the tolerance to stress and the potential application against potato late blight of these antagonistic isolates were tested. Most of them were extremely tolerant to stresses such as acid–alkali, temperature, UV, salt, and heavy metal stress. However, some antagonistic isolates with excellent stress tolerance might be pathogenic to potatoes. Combining the screening results, a total of 14 endophytes had excellent comprehensive performance in all the tests. In this paper, the endophyte 6-5 was selected among them for the preliminary exploration of the anti-oomycete mechanism. Analysis of the 16S rDNA sequence revealed that 6-5 had a high homology to the corresponding sequence of Bacillus velezensis (99.72%) from the NCBI database. Endophyte 6-5 significantly inhibited the mycelial growth of P. infestans, with an inhibition rate of over 90% in vitro assays, and deformed the hyphal phenotype of P. infestans. In addition, endophyte 6-5 could secrete protease and cellulase, and produce antagonistic substances with high thermal stability, which might be helpful to its antagonistic activity against P. infestans. Furthermore, it was demonstrated that 6-5 had the ability to improve the resistance of potato tubers to late blight. In short, our study described the process of isolating and screening endophytes with antagonistic activity against P. infestans from potato roots, and further explored the potential of biocontrol candidate strain 6-5 in potato late blight control.

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The hunt for sustainable biocontrol of oomycete plant pathogens, a case study of Phytophthora infestans

Cited by 31 publications

References 97 publications

Evaluating the Antagonistic Potential of Actinomycete Strains Isolated From Sudan’s Soils Against Phytophthora infestans

Evaluating the Antagonistic Potential of Actinomycete Strains Isolated From Sudan’s Soils Against Phytophthora infestans

Investigating the Biocontrol Potential of the Natural Bacterial Flora of the Apple Blossom

Isolation and Screening of Antagonistic Endophytes against Phytophthora infestans and Preliminary Exploration on Anti-oomycete Mechanism of Bacillus velezensis 6-5

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