In vitro Antagonism of Phytophthora cinnamomi and P. citricola by Isolates of Trichoderma spp. and Gliocladium virens

ABSTRACT Despite the favorable edaphoclimatic conditions for avocado production in Brazil, diseases such as root rot caused by the pathogen Phytophthora cinnamomi compromise the crop. With the aim of managing root rot in avocado, the present study aimed to evaluate chemical and biological control with isolates of Trichoderma spp. and Pseudomonas fluorescens. Thus, three assays were conducted to assess: (i) mycelial inhibition of P. cinnamomi by isolates of Trichoderma spp. and P. fluorescens from different crop systems; (ii) effect of autoclaved and non-autoclaved metabolites of P. fluorescens, and (iii) chemical or biological treatment of avocado seedlings on the control of root rot under field conditions. The isolates of Trichoderma spp. from maize cultivation soil and the commercial products formulated with Trichoderma presented greater antagonism (p <0.05) to the pathogen P. cinnamomi in the in vitro tests. Similarly, non-autoclaved metabolites of P. fluorescens presented antagonistic potential to control P. cinnamomi. Under field conditions, the fungicide metalaxyl and the bioagents showed effectiveness in controlling P. cinnamomi, as well as greater root length and mass. Results demonstrated potential for the biological control of avocado root rot with Trichoderma spp. and P. fluorescens.

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Evaluación de la capacidad antagónica in vitro de cepas de Trichoderma spp frente a Phytophthora cinnamomi, fitopatógeno de Persea americana (Palta)

Ciencia e Investigación ◽

10.15381/ci.v23i1.18754 ◽

2020 ◽

Vol 23 (1) ◽

pp. 65-70

Author(s):

Ebeling M. Morales T. ◽

Mirko D. Lino N. ◽

Eddy Ortega R. ◽

Pedro L. Castellanos S.

Keyword(s):

Phytophthora Cinnamomi ◽

Persea Americana ◽

Trichoderma Asperellum ◽

Trichoderma Spp

Phytophthora cinnamomi es un fitopatógeno reportado como el agente causal de la pudrición radicular del palto en el Perú. En este estudio se evaluó la capacidad antagónica de cepas nativas de Trichoderma spp aisladas de la rizósfera de un cultivo de paltos del distrito de Quilmaná, Cañete. Para la evaluación in vitro de la capacidad antagónica de las cepas aisladas se utilizó la técnica de cultivo dual en donde se midió los porcentajes de inhibición del crecimiento radial (PICR) de P. cinnamomi. Del total de cepas aisladas, 3 (P1.1, P4.9 y P5.3) presentaron mayores PICR con 53.86, 56,24 y 60,49 % respectivamente. La identificación molecular indicó que la cepas P4.9 y P1.1 presentan un 99,66 y 100% de similitud con Trichoderma asperellum mientras que la cepa P5.3 un 98,17% de similitud con Trichoderma spp, según el análisis BLAST. En base a los resultados obtenidos estas cepas de Trichoderma asperellum representan un potencial para ser utilizadas como agentes biocontroladores de P. cinnamomi. por lo que se recomienda realizar ensayo en campo.

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Endophytic Trichoderma Species Isolated from Persea americana and Cinnamomum verum Roots Reduce Symptoms Caused by Phytophthora cinnamomi in Avocado

Plants ◽

10.3390/plants9091220 ◽

2020 ◽

Vol 9 (9) ◽

pp. 1220

Author(s):

Petra Andrade-Hoyos ◽

Hilda Victoria Silva-Rojas ◽

Omar Romero-Arenas

Keyword(s):

Root Rot ◽

Phytophthora Cinnamomi ◽

Disease Incidence ◽

Persea Americana ◽

Dual Culture ◽

Internal Transcribed Spacer Region ◽

Trichoderma Spp ◽

Trichoderma Species ◽

Potato Dextrose Agar Medium

Avocado root rot caused by the oomycete Phytophthora cinnamomi is a severe disease that affects avocado production in Mexico and worldwide. The use of biological control agents such as Trichoderma species isolated from places where the disease is always present, represents an efficient alternative to reduce losses. Thus, the objective of this research was to evaluate the biocontrol ability of 10 endophytic Trichoderma spp. strains against P. cinnamomi tested both in vitro and in the greenhouse. The endophytic Trichoderma spp. were recovered from Persea americana and Cinnamomum verum roots, isolated and purified on potato–dextrose–agar medium. Ten strains were identified by phylogenetic reconstruction of the internal transcribed spacer region of rDNA sequences as T. asperellum (T-AS1, T-AS2, T-AS6, and T-AS7), T. harzianum (T-H3, T-H4, and T-H5), T. hamatum (T-A12), T. koningiopsis (T-K8 and T-K11), and P. cinnamomi (CPO-PCU). In vitro dual-culture assay, the percentage of inhibition of radial growth (PIRG) between Trichoderma spp. and P. cinnamomi strains was measured according to the Bell’s scale. PIRG results indicated that T-AS2 reached the highest value of 78.32%, and T-H5 reached the lowest value of 38.66%. In the greenhouse, the infection was evaluated according to the percentage of disease incidence. Plants with the lowest incidence of dead by avocado root rot were those whose seedlings were inoculated with T-AS2 and T-AS7, resulting in only 5% death by root rot caused by P. cinnamomi. The disease incidence of seedlings with wilt symptoms and death decreased more than 50% in the presence of Trichoderma spp. Relying on the results, we conclude that T. asperellum and T. harzianum contribute to the biocontrol of soil-borne pathogenic oomycete P. cinnamomi.

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An Attempt at Biological Control of Blossom Blight of Rose Caused by Botrytis cinerea Using some Local Trichoderma spp. Strains

Acta Phytopathologica et Entomologica Hungarica ◽

10.1556/038.55.2020.010 ◽

2020 ◽

Vol 55 (1) ◽

pp. 27-34

Author(s):

G. Zadehdabagh ◽

K. Karimi ◽

M. Rezabaigi ◽

F. Ajamgard

Keyword(s):

Botrytis Cinerea ◽

Mycelial Growth ◽

Limiting Factor ◽

Dual Culture ◽

Trichoderma Spp ◽

Khuzestan Province ◽

Inhibitory Potential ◽

Cut Rose

The northern of Khuzestan province in Iran is mainly considered as one of the major areas of miniature rose production. Blossom blight caused by Botrytis cinerea has recently become a serious limiting factor in rose production in pre and post-harvest. In current study, an attempt was made to evaluate the inhibitory potential of some local Trichoderma spp. strains against B. cinerea under in vitro and in vivo conditions. The in vitro results showed that all Trichoderma spp. strains were significantly able to reduce the mycelial growth of the pathogen in dual culture, volatile and non-volatile compounds tests compared with control, with superiority of T. atroviride Tsafi than others. Under in vivo condition, the selected strain of T. atroviride Tsafi had much better performance than T. harzianum IRAN 523C in reduction of disease severity compared with the untreated control. Overall, the findings of this study showed that the application of Trichoderma-based biocontrol agents such as T. atroviride Tsafi can be effective to protect cut rose flowers against blossom blight.

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ANTAGONISMO in vitro DE Trichoderma spp. A PATÓGENOS DO CACAUEIRO

Agrotrópica (Itabuna) ◽

10.21757/0103-3816.2013v25n2p117-120 ◽

2013 ◽

Vol 25 (2) ◽

pp. 117-120 ◽

Cited By ~ 1

Author(s):

Bruno Ferreira de Oliveira ◽

Stela Dalva Vieira Midlej Silva ◽

Marcos Vinícius Oliveira dos Santos

Keyword(s):

Trichoderma Spp

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Management of collar rot disease in chickpea by Trichoderma species

Journal of AgriSearch ◽

10.21921/jas.v7i03.18694 ◽

2020 ◽

Vol 7 (03) ◽

Author(s):

PREM PANDEY ◽

G. C. SAGAR ◽

SUNDARMAN SHRESTHA2 ◽

HIRAKAJI MANANDHAR ◽

RITESH K. YADAV ◽

...

Keyword(s):

Growth Inhibition ◽

Mycelial Growth ◽

Sclerotium Rolfsii ◽

Maximum Growth ◽

Pot Experiment ◽

Trichoderma Spp ◽

Trichoderma Species ◽

Collar Rot ◽

Rot Disease

Nine isolates of Trichoderma spp. were isolated from different agro- ecological regions of Nepal viz; Jumla, Palpa, Chitwan, Tarahara, Banke, Illam and Salyan and screened against Sclerotium rolfsii Sacc. Adreded soil borne phytopathogen causing collar rot of chickpea in chickpea; In-vitro efficacy of nine fungal antagonist (Trichoderma spp.) against Sclerotium rolfsii were screened. Pot experiment was done to find out the effective management of S. rolfsi through Tricoderma using different methods i.e. Seed treatment, soil drenching and soil application. All the tested isolates of Trichoderma spp. were found effective on mycelial growth inhibition and sclerotial parasitization of S. rolfsii. Trichoderma isolated from Palpa district showed maximum growth inhibition (%) of pathogen periodically after 48(93.78%), 72(96.00%), 96(97.96%) and 120(100.00%) hours of inoculation. Parasitized sclerotium showed minimum sclerotial germination on agar plates. Moreover, Trichoderma species isolated from Palpa districts showed second best percent mycelial growth inhibition periodically at 72(25.00%), 120(29.16%), 168(29.16%) and 216(29.16%).In pot experiment at 40 days after sowing, Seedling height was maximum in soil drenching with 30g per 100ml of water (22.27cm) and Mortality percentage of seedlings was least or highest disease control was observed in seed treated with 109cfu/ml (0.000%).

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Cellulase Activity as a Mechanism for Suppression of Phytophthora Root Rot in Mulches

Phytopathology ◽

10.1094/phyto-04-10-0125 ◽

2011 ◽

Vol 101 (2) ◽

pp. 223-230 ◽

Cited By ~ 16

Author(s):

Brantlee Spakes Richter ◽

Kelly Ivors ◽

Wei Shi ◽

D. M. Benson

Keyword(s):

Root Rot ◽

Phytophthora Cinnamomi ◽

Cellulase Activity ◽

Enzyme Concentration ◽

Disease Suppression ◽

In Vitro Assays ◽

Infested Soil ◽

Phytophthora Root Rot ◽

Standard Curve

Wood-based mulches are used in avocado production and are being tested on Fraser fir for reduction of Phytophthora root rot, caused by Phytophthora cinnamomi. Research with avocado has suggested a role of microbial cellulase enzymes in pathogen suppression through effects on the cellulosic cell walls of Phytophthora. This work was conducted to determine whether cellulase activity could account for disease suppression in mulch systems. A standard curve was developed to correlate cellulase activity in mulches with concentrations of a cellulase product. Based on this curve, cellulase activity in mulch samples was equivalent to a cellulase enzyme concentration of 25 U ml–1 or greater of product. Sustained exposure of P. cinnamomi to cellulase at 10 to 50 U ml–1 significantly reduced sporangia production, but biomass was only reduced with concentrations over 100 U ml–1. In a lupine bioassay, cellulase was applied to infested soil at 100 or 1,000 U ml–1 with three timings. Cellulase activity diminished by 47% between 1 and 15 days after application. Cellulase applied at 100 U ml–1 2 weeks before planting yielded activity of 20.08 μmol glucose equivalents per gram of soil water (GE g–1 aq) at planting, a level equivalent to mulch samples. Cellulase activity at planting ranged from 3.35 to 48.67 μmol GE g–1 aq, but no treatment significantly affected disease progress. Based on in vitro assays, cellulase activity in mulch was sufficient to impair sporangia production of P. cinnamomi, but not always sufficient to impact vegetative biomass.

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Allelopathic Effects of Three Herb Species on Phytophthora cinnamomi, a Pathogen Causing Severe Oak Decline in Mediterranean Wood Pastures

Forests ◽

10.3390/f12030285 ◽

2021 ◽

Vol 12 (3) ◽

pp. 285

Author(s):

Manuela Rodríguez-Romero ◽

Belén Godoy-Cancho ◽

Isabel M. Calha ◽

José António Passarinho ◽

Ana Cristina Moreira

Keyword(s):

Phytophthora Cinnamomi ◽

Raphanus Raphanistrum ◽

Inhibitory Capacity ◽

Pathogen Suppression ◽

Pathogen Populations ◽

Defensive Chemical ◽

Chemical Response ◽

Herb Species

The ability of three herbaceous plants (Diplotaxis tenuifolia (L.) DC., Eruca vesicaria L. and Raphanus raphanistrum L.) from Iberian wood pastures to reduce Phytophthora cinnamomi Rands pathogen populations through allelopathic relationships is studied. The inhibitory capacity of their aqueous root extracts (AREs) on mycelial growth and production of P. cinnamomi reproductive structures is analysed in vitro. In addition, Quercus seedlings were grown in infested by P. cinnamomi-soils and with the presence or absence of allelopathic and susceptible herb species to the pathogen to assess the defensive chemical response of Quercus seedlings through their leaf phenolic compounds. Results show a strong inhibitory capacity of AREs on P. cinnamomi activity in vitro and a protective effect of these herb species on Quercus plants against P. cinnamomi in vivo. D. tenuifolia would be especially suited for biological control in the pathogen suppression.

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Control of lettuce bottom rot by isolates of Trichoderma spp

Summa Phytopathologica ◽

10.1590/0100-5405/1968 ◽

2014 ◽

Vol 40 (2) ◽

pp. 141-146 ◽

Cited By ~ 4

Author(s):

Zayame Vegette Pinto ◽

Matheus Aparecido Pereira Cipriano ◽

Amaury da Silva dos Santos ◽

Ludwig Heinrich Pfenning ◽

Flávia Rodrigues Alves Patrício

Keyword(s):

Mycelial Growth ◽

High Capacity ◽

Dry Weight ◽

Second Step ◽

Trichoderma Spp ◽

In Vivo Experiments ◽

Bottom Rot ◽

Trichoderma Isolates

Bottom rot, caused by Rhizoctonia solani AG 1-IB, is an important disease affecting lettuce in Brazil, where its biological control with Trichoderma was not developed yet. The present study was carried out with the aim of selecting Trichoderma isolates to be used in the control of lettuce bottom rot. Forty-six Trichoderma isolates, obtained with baits containing mycelia of the pathogen, were evaluated in experiments carried out in vitro and in vivo in a greenhouse in two steps. In the laboratory, the isolates were evaluated for their capabilities of parasitizing and producing toxic metabolic substances that could inhibit the pathogen mycelial growth. In the first step of the in vivo experiments, the number and the dry weight of lettuce seedlings of the cultivar White Boston were evaluated. In the second step, 12 isolates that were efficient in the first step and showed rapid growth and abundant sporulation in the laboratory were tested for their capability of controlling bottom rot in two repeated experiments, and had their species identified. The majority of the isolates of Trichoderma spp. (76%) showed high capacity for parasitism and 50% of them produced toxic metabolites capable of inhibiting 60-100% of R. solani AG1-IB mycelial growth. Twenty-four isolates increased the number and 23 isolates increased the dry weight of lettuce seedlings inoculated with the pathogen in the first step of the in vivo experiments.In both experiments of the second step, two isolates of T. virens, IBLF 04 and IBLF 50, reduced the severity of bottom rot and increased the number and the dry weight of lettuce seedlings inoculated with R. solani AG1-IB. These isolates had shown a high capacity for parasitism and production of toxic metabolic substances, indicating that the in vitro and in vivo steps employed in the present study were efficient in selecting antagonists to be used for the control of lettuce bottom rot.

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Cuticular disruption and mortality of Caenorhabditis elegans exposed to culture filtrate of Byssochlamys nivea Westling

Nematology ◽

10.1163/156854101317020277 ◽

2001 ◽

Vol 3 (4) ◽

pp. 355-363 ◽

Cited By ~ 3

Author(s):

Ja-On Park ◽

Krishnapillai Sivasithamparam ◽

Emile Ghisalberti ◽

Jaih Hargreaves ◽

Walter Gams ◽

...

Keyword(s):

Caenorhabditis Elegans ◽

Culture Filtrate ◽

Structural Changes ◽

Phytophthora Cinnamomi ◽

Pathogenic Fungi ◽

Gaeumannomyces Graminis ◽

Pythium Irregulare ◽

Potato Dextrose Broth ◽

C Elegans

AbstractA strain of a Byssochlamys nivea, isolated from saline mud in Western Australia as a part of statewide survey of soil fungi for nematophagous activity, was evaluated for its effect on nematodes. Culture filtrate of the fungus grown on potato dextrose broth for 7 days caused structural changes in the cuticle, aggregation of individuals, and mortality of Caenorhabditis elegans. In addition, the culture filtrate completely inhibited hatching of C. elegans eggs. Exudates from agar colonies also caused cuticular disruption and mortality of C. elegans. The cuticular disruption observed, not reported in nematodes before, was initiated in the labial region and spread towards the posterior region of the nematode within 10 min of application. This reaction occurred only in live nematodes. Cuticular disruption and mortality caused by the culture filtrate varied according to growth conditions. The active compound(s) in the culture filtrate were thermostable (100°C for 1 h); however freezing the culture filtrate (-20°C for 2 days) eliminated the activities, as did dialysis (<14 000 molecular weight). Cuticular disruption and mortality were also observed when the nematode was exposed to culture filtrates of two other strains of B. nivea supplied by CBS, The Netherlands. The culture filtrate also inhibited in vitro growth of the plant-pathogenic fungi Fusarium oxysporum, Gaeumannomyces graminis var. tritici, Phytophthora cinnamomi, Pythium irregulare and Rhizoctonia solani.

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