Phytophthora Palmivora Research Articles

Effect of secondary metabolites of Trichoderma spp. in inhibiting Phytophthora palmivora growth in cacao (Theobroma cacao L.)

Secondary metabolites are organic compounds produced by microorganisms or plants which are not directly involved to development and reproduction. The secondary metabolites produced by Trichoderma spp. are antibiotic compounds, enzymes, toxins, and hormones that inhibit the growth of plant pathogens. Phytophthora palmivora is a pathogen that causes black pod, leaf blight, and stem canker in cacao, which potentially reduce production up to 40%. This study was aimed to determine the inhibitory effect of Trichoderma spp. secondary metabolites against P. palmivora. Isolates of Trichoderma spp., i.e. T. virens LP1, T. hamatum LP2, T. amazonicum LP3, T. atroviride JB2, and T. viride PRD were cultured on vegetative and generative medium, then their secondary metabolites was extracted using butanol and ethyl acetate. Analysis of the extracts of secondary metabolite was performed using HPLC to determine their chromatogram profile. The secondary metabolites obtained were tested against P. palmivora using poisoned-medium method and cacao seedlings. In vitro inhibition activity, disease severity, and growth of cacao seedlings were observed. The results showed that extraction of the secondary metabolite using butanol produces more metabolites than those using ethyl acetate. Secondary metabolites of T. virens LP1 and T. amazonicum LP3, significantly inhibited P. palmivora growth up to 90.98%. In general, secondary metabolites of Trichoderma spp. can suppress P. palmivora infection (60.02%–70.00%) in cacao seedlings.

A secreted protein of 15\u2009kDa plays an important role in Phytophthora palmivora development and pathogenicity

Phytophthora palmivora is a destructive oomycete plant pathogen with a wide host range. So far, little is known about the factors governing its infection structure development and pathogenicity. From the culture filtrate of a P. palmivora strain isolated from papaya, we identified a secreted glycoprotein of 15 kDa, designated as Ppal15kDa, using liquid chromatography tandem mass spectrometry. Two gene variants, Ppal15kDaA and Ppal15kDaB were amplified from a P. palmivora papaya isolate. Transient expression of both variants in Nicotiana benthamiana by agroinfiltration enhanced P. palmivora infection. Six Ppal15kDa mutants with diverse mutations were generated via CRISPR/Cas9-mediated gene editing. All mutants were compromised in infectivity on N. benthamiana and papaya. Two mutants with all Ppal15kDa copies mutated almost completely lost pathogenicity. The pathogenicity of the other four containing at least one wild-type copy of Ppal15kDa was compromised at varying levels. The mutants were also affected in development as they produced smaller sporangia, shorter germ tubes, and fewer appressoria. The affected levels in development corresponded to the levels of reduction in pathogenicity, suggesting that Ppal15kDa plays an important role in normal development of P. palmivora infection structures. Consistent with its role in infection structure development and pathogenicity, Ppal15kDa was found to be highly induced during appressorium formation. In addition, Ppal15kDa homologs are broadly present in Phytophthora spp., but none were characterized. Altogether, this study identified a novel component involved in development and pathogenicity of P. palmivora and possibly other Phytophthora spp. known to contain a Ppal15kDa homolog.

Evaluation of the Epidemiological Factors Responsible for the Appearance of Phytophthora Palmivora and Phytophthora Megakarya, Causal Agent of Black Pods Disease in the Department of Méagui, Southwestern Côte D'ivoire

The cocoa black pod disease is caused by a fungus Phytophthora sp, which comprises two main species (Phytophthora palmivora and Phytophthora megakarya) commonly found in Ivorian cocoa plots and which cause significant damage. Despite numerous studies, this disease continues to spread and even more so Phytophthora megakarya, which did not exist in Côte d'Ivoire, is beginning to spread significantly. This study focused on the evaluation of the epidemiological factors responsible for the progression of Phytophthora megakarya and Phytophthora palmivora in the Department of Méagui, southwestern Cote d'Ivoire. To this end, a prospective survey was conducted in three cocoa plots in Méagui, which collected epidemiological data on

Control of Conopomorpha cramerella, Helopeltis sp., and Phytophthora palmivora using botanical and biological pesticides

Control of main pests and diseases of cocoa using biopesticides has been carried out on a 10 ha farmer land in the village of Liliariawang, South Sulawesi. The aim is to determine the effectiveness of α-elaeostearic acid and Citronellal formulas of botanical pesticides, and Beauveria bassiana of biological pesticide on pod borer (Conopomorpha cramerella), fruit suckers (Helopeltis spp.), and fruit rot (Phytophthora palmivora) of cocoa. The treatments were arranged in a randomized group. Sampling was carried out systematically as much as 120 healthy cocoa fruits <8 cm long from about 40 sample plants in each treatment to observe the extent of damage. The sample fruits are sprayed treatments every 2 weeks until harvest. Observations were made on the degree of damage to the fruits and their effects on non-target organisms such as natural enemies of pests. The results shows that both of botanical pesticides and biological pesticide can reduce the intensity attacks of the cocoa pests and diseases. Yield loss in all treatments were below 10%, lower and significantly different compared to control which reach 36,5%. In addition to reducing damage caused by pests, the quality and weight of the cocoa beans produced was better than the control.

Effect of Trichoderma spp. and potassium fertilizer on Phytophthora palmivora infection in cacao seedlings

Phytophthora palmivora is a pathogen that causes black pod, leaf blight, and stem cancer on cacao, that cause yield loss up to 40%. Control of P. palmivora is intended to make plants healthy, by using Trichoderma spp. and potassium fertilizer. The study was aimed to determine the effect of Trichoderma spp. and potassium fertilizer application against P. palmivora infection in cacao seedlings. The study used a randomized block design consisting of 13 treatments with 5 replications. The treatments were Trichoderma spp. (T. atroviride JB2, T. amazonicum LP3, T. hamatum LP2), and potassium fertilizers dosages (1, 2 and 3 g), chemical fungicides (mancozeb) for comparison, and control. Cacao seedlings were treated with Trichoderma spp. and potassium fertilizer, then the plants were inoculated with P. palmivora. Observations were on attack symptoms, incubation period, disease severity, growth of cacao seedlings, and lignin content. The results showed that the application of Trichoderma spp. and potassium fertilizer prolonged the incubation period and reduced the number of leaves spots (48.95–75.37%). T. amazonicum + 3 g of potassium fertilizer and T. hamatum + 2 g of potassium fertilizer suppressed the number of spots up to 75.37% and 71.36% respectively, higher than chemical fungicides that were 70.86%.

Analysis of Liquid Volatile Matters from Coconut Shell Pyrolysis by GC-MS and Its Potential as Antifungal Agent

Indonesia is one of the highest producers of coconut in the world and at the same time coconut shell waste is also high. This study used gas chromatography-mass spectrometric (GC-MS) analysis for the liquid volatile matter (LVM) generated from coconut shell pyrolysis and to examine its potential as an antifungal agent. Pyrolysis was performed at 600 ºC. The LVM was 29% (v/w) and had pH 3 and 1.087 g mL-1 density. To determine chemical constituents using GC-MS, the standard NIST MS software was used. The spectrogram analysis of LVM revealed five main compounds, namely phenol (21.92%); (Z)-4-methyl-5-(2-oxopropylidene)-5H-furan-2-one (13.06%); 2,6-dimethoxyphenol (11.54%); 2-methoxyphenol (9.07%) and 2-hydroxy-3-methyl-2-cyclopenten-1-one (7.66%). The LVM showed a excellent fungicidal activity against Phytophthora palmivora at a concentration of 0.125% (v/v).

Chlorophyll a fluorescence and leaf temperature are early indicators of oil palm diseases

Bud rot (BR) caused by Phytophthora palmivora and lethal wilt (LW) whose causal agent is unknown, are two diseases currently posing a threat to the oil palm ( Elaeis guineensis . Jacq) industry. BR, first reported in 1964, has destroyed more than 85,000 ha. LW, first reported in 1994 in the Llanos Orientales in Colombia, has destroyed more than 5,000 ha. Chlorophyll a fluorescence is useful as a provider of information about the efficiency of the photosynthetic process when plants are subjected to biotic or abiotic stresses. Oil palms affected by BR and LW showed anomalies in the photosynthetic system, manifested by reductions in Fv / F M and ΦPSII. Changes in ΦPSII, variable fluorescence yield ( Fv ) and maximum fluorescence in light-adapted leaves ( F M ’ ) were observed from the start of BR infection. The most sensitive and early indicators of LW disease were leaf temperature and basal fluorescence ( F 0 ). Fv/F 0 significantly changed in diseased palms, indicating problems with movement of electrons through the electron transport chain. Leaf temperature changed in response to both diseases, but variation was greater in LW. We concluded that damage to the photochemical system caused by the diseases affected the processes by which the plant captures and transports energy, causing a physiological imbalance in the plant reflected in the observed variations in chlorophyll a fluorescence and leaf temperature. The two parameters began to change early in the onset of BR and before visual symptoms appeared in LW, which is very important to the management of both diseases, the foundation of which is early detection.

Phytophthora sp a causal agent of leaf soft rot disease of nutmeg in Indonesia

Leaf soft rot symptom has been found in nutmeg germplasm collection of Indonesian Spices and Medicinal Crop Research Institute (ISMCRI), Sukabumi, West Java. The research was aimed to identify a causal agent of leaf soft rot disease and the effectiveness assay of fungicides on colonies growth. Based on morphological observations, Phytophthora was found consistently from the infected leaf samples and the fungus characteristic was identic to Phytophthora palmivora. Host range test showed the ability of the fungus to infect pepper and rubber plants. The effect of temperature on fungal growth was tested by planting the fungus on Carrot Agar Medium (CAM), and incubated at 25°C, 28°C, 31°C and 34°C. The efficacy of propineb and mancozeb on inhibiting the growth of fungal colonies was tested by food poisoning technique. Koch’s postulate test showed that the first soft rot symptom on the inoculated leaves appeared on the second day and the infected leaves began to fall on the fourth day after inoculation. The optimum temperature for the fungus to grow is 28°C. The result of the efficacy test showed that mancozeb was more suppressing the growth of the Phytophthora than propineb

PENGAMATAN GEJALA INFEKSI Phytophthora palmivora PENYEBAB PENYAKIT BUSUK BUAH PADA KAKAO

Phytophthora palmivora is a patogen fungi causing pod rot disease in cacao plants. Thr researchof effectivity examination of biopesticide (active ingredient Aspergillus sp.) againts the growth of P. Palmivora in cacao pod (Theobroma cacao L.) by in vivo state was conducted from March 2018 to September 2018. This research was carried out in Sidondo Village, Dolo Subdistrict, Sigi Biromaru District, Central Sulawesi Province and Laboratory of Biotechnology, Faculity of Mathematics and Natural Sciences, Tadulako University. This study was aimed to determine an effective biopesticide (active ingredient Aspergillus sp.) which suppresses the growth of P. Palmivora in cacao pod by in vivo state and to stipulate the most affective biopesticide concentration (active ingredient Aspergillus sp.) in suppressing the growth of of P. Palmivora in cacao pod by in vivo state. This This research was by using the methods of Group Random Design (GRD) or Rancangan Acak Kelompok (RAK) consisting of six treatmentsand four repetitions. The observation parameters consist of symptoms of disease, the lenght of infection spots, the infection persentage of P. Palmivora, microscopic observations, in the microscopic of P. Palmivora. The results showed that the biopesticide (active ingredient Aspergillus sp.) was varified as effective in controlling P. Palmivora drawing the rot disease bin cacao plants, by the absent of any symptoms of infection P1,P2,P3,P4 dan P5 treatments. The only treatments in which was infected by P. Palmivora , drawing the rot disease in cacao plants, was P0 with the occurence time of infection symptoms was in the third day after inoculation, the average lenght of infection spots was 8,65 cm and the average infection persentage was 11,60%.

Widely distributed variation in tolerance to Phytophthora palmivora in four genetic groups of cacao

The tropical tree Theobroma cacao is the source of chocolate, and its seeds are a major export from many producing countries in Central and South America, Africa, and Asia. Every year, 30–40% of pre-harvest yield is lost due to disease damage. Host plant resistance is the most efficient and environmentally friendly approach for disease management. Historically, cacao germplasm resources have been underutilized in efforts to introduce novel sources of disease tolerance into breeding programs. Maintenance of cacao germplasm also relies on clonally propagated live collections, as cacao seeds do not exhibit dormancy and cannot be stored for more than a few weeks. In this study, we use a 90 SNP array to verify genetic identity of a set of clones in the International Cocoa Collection at CATIE, Costa Rica, and assign the clones into known genetic groups. We also used a detached leaf inoculation technique to measure the susceptibility of 60 genotypes to Phytophthora palmivora, a major cacao pathogen with global importance. We identified 24 genotypes with disease tolerance statistically similar to a standard tolerant variety (SCA6) and another 24 which performed similarly to a standard susceptible variety (ICS1). Our results indicate that each of the four included genetic groups show variability for quantitative resistance to P. palmivora. These results provide a foundation for future genomic and transcriptomic analysis of disease tolerance and susceptibility in the field at CATIE and provide guidelines for breeders searching for novel sources of tolerance that can be introduced into breeding programs.

Antifungal Efficacy of Crude Aqueous Weed Extracts Against Pathogen of Cocoa Black Pod Rot

Black pod rot is the most economically important disease of cocoa in Malaysia which is mainly caused by a highly polyphagous Phytophthora species, called Phytophthora palmivora. The fungus could attack all parts of the cocoa plant organs and caused various diseases at any growth stage from seedling until the mature stages, especially during raining season. The application of synthetic fungicides has been widely recommended to manage the disease but their repeated use had led to other problems such as environmental, human health and development of fungicide resistance issues. This study isolated and identified Phytopththora isolate from a cocoa pod sample based on micro-morphological characters. Besides, the present investigation was undertaken to screen for the antifungal potency of different weed extracts against the Phytophthora pathogen using poisoned food technique. The fungal isolate was successfully recovered from pod tissues of clone PBC123 on 20% tomato juice agar culture (20T). Only one out of ten weed extracts tested showed a significant in vitro inhibitory effect towards mycelial growth of Phytophthora isolate, which was aqueous crude leaf extract of Solanum torvum (42.68%). This study indicated that the potential of weed extracts in the management of Phytophthora diseases, and may offer more natural, effective and economical control methods.

N-acetyltransferase AAC(3)-I confers gentamicin resistance to Phytophthora palmivora and Phytophthora infestans

BackgroundOomycetes are pathogens of mammals, fish, insects and plants, and the potato late blight agent Phytophthora infestans and the oil palm and cocoa infecting pathogen Phytophthora palmivora cause economically impacting diseases on a wide range of crop plants. Increasing genomic and transcriptomic resources and recent advances in oomycete biology demand new strategies for genetic modification of oomycetes. Most oomycete transformation procedures rely on geneticin-based selection of transgenic strains.ResultsWe established N-acetyltransferase AAC(3)-I as a gentamicin-based selectable marker for oomycete transformation without interference with existing geneticin resistance. Strains carrying gentamicin resistance are fully infectious in plants. We further demonstrate the usefulness of this new antibiotic selection to super-transform well-characterized, already fluorescently-labelled P. palmivora strains and provide a comprehensive protocol for maintenance and zoospore electro-transformation of Phytophthora strains to aid in plant-pathogen research.ConclusionsN-acetyltransferase AAC(3)-I is functional in Phytophthora oomycetes. In addition, the substrate specificity of the AAC(3)-I enzyme allows for re-transformation of geneticin-resistant strains. Our findings and resources widen the possibilities to study oomycete cell biology and plant-oomycete interactions.

Renewable sources: applications in personal care formulations.

A global tendency for products considered environmentally sustainable, and ecologically obtained led the industry related to personal care formulations to fund the research and the development of personal care/cosmetics containing ingredients from natural resources. Furthermore, consumers are aware of environmental and sustainability issueans, thus not harming the environment represents a key consideration when developing a new cosmetic ingredient. In this study we review some examples of active ingredients or raw materials used in cosmetics/personal care/biomedical products that are coming from either through biotechnological systems, or as byproducts of several industries. A skin formulation containing biosynthetic actives, prepared by us and the study regarding its dermocosmetic properties are also described. The need for the standardization processes, the safety assessment tools, the improvement of the exploitation methods of these renewable sources in order the production to be ecologically and economically better are also discussed.

A new approach for identifying antagonism among fungi species and antifungal activity

New antifungals are increasingly needed due to the emergence of resistant fungal strains. Traditional antifungal assays are laborious and require significant amounts of samples. The present work presents a new proposal to evaluate antifungal activity and antagonism among fungal species, based on experiments of fungal culture and co-culture, 1H NMR profile of fungal culture extracts and chemometrics. In order to develop the work, six axenic cultures of fungi that infested fruits (Fusarium guttiforme, Pestalotiopsis diospyri, Phoma caricae-papayae, Colletotrichum horii, Phytophthora palmivora, and C. gloeosporioides), and co-cultures of all possible combination among them were performed (totalizing 63 experiments). All fungal extracts were evaluated by 1H NMR followed by Principal Component Analyses (PCA) in order to determine spectral dissimilarity among the extracts. Results showed that 1H NMR data evaluated by PCA were capable to predict both antagonism and antifungal activity. Traditional antifungal in vitro assays of active and inactive extracts were also performed in order to prove the prediction made by PCA. The obtained data showed that the approach is an outstanding tool to simultaneously obtain and evaluate bioactive compounds because: it was able to predict the activity of five different extracts in a collection of sixty-three, which would be much more difficult and time consuming if applied randomly; most important antifungal extracts are indicated by PCA; hundreds of traditional in vitro assays are avoid; and, the method is very time and money saving.

ORGANIC FERTILIZER AMENDMENTS REDUCE DISEASE SEVERITY OF Phytophthora palmivora ROOT ROT OF DUKU (Lansium domesticum) SEEDLING

Phytophthora palmivora, is a deadly pathogen of duku, causing serious problem in the main production area, especially in Jambi Province, Indonesia. The pathogen can infect duku plant in all stage of growth including seedlings. Organic amended media might become a potential alternative option for this disease management. These studies were performed in soil media containing organic fertilizer of 0%, 10%, 20%, 30% (v/v), served as treatment, and subjected to completely randomized design with 5 replications. This research found that incorporating 20% of organic fertilizer into media was able to lower disease severity by 23%. The ability of organic fertilizer to increase media bacterial and maintain fungal density and increase chemicals of C-org, P, K, Ca, Mg and Zn played important roles in reducing disease development.

Cocoa Clone Resistance to Phytophthora Pod Rot (PPR) and Cocoa Pod Borer (CPB) in South Sulawesi

This research aimed find out the resistant of some superior cocoa clones to Phytophthora palmivora in South Sulawesi. This research covers several stages ranging from selection and sampling of cocoa clones, pathogen exploration to cocoa clone’s resistant test with various methods that is attaching the cocoa pod part to the healthy cocoa pod, applying P. palmivora suspension to the cocoa surface and sticking P. Palmivora isolates to the healthy cocoa pod section. The results showed that the resistance of cocoa clones to the three inoculation methods showed different areas of spotting on each observation day. The three application methods show that different applications can affect the difference in infection rates in each cocoa pod clone so that the spots that arise from infection can occur in various ways.

Relationship between soil microbes and plant pathogens of Ziziphus zizyphus in Nokrek biosphere reserve of Garo hills of Meghalaya

Wild Indian plum (Ziziphus zizyphus), locally known as ‘angkil’, is a rich source of vitamin C and contains minerals and proteins. The ripe fruits are mostly consumed fresh. Processed products like candy, pickle, chutney and jelly are also prepared from fruits. The young plants are used for making hedges and leaves are used as fodder. The objective of the study was to identify the disease causing pathogens in Z. zizyphus and soil microbes inhabiting the rhizosphere of this plant in the three zones of Nokrek Biosphere Reserve, as well as to assess the relationship between soil microbes and occurrence of plant pathogens. Eight diseases caused by fungal pathogens and one disease caused by algae were observed. Change in zone showed significant influence on occurrence of plant pathogens. Occurrence of soil microbes in the rhizosphere was significantly influenced by change in soil depth and season. Soil microbes were found to be more in top soil than subsoil. Soil microbes Fusarium oxysporum and Phytophthora palmivora inhabiting the rhizosphere of Z. zizyphus at 0–15 cm soil depth had a significant positive association with plant pathogens, Colletotrichum acutatum, Cercospora ziziphii and Cladosporium ziziphii while exerting an antagonistic effect on pathogens like Oidium erysiphoides, Colletotrichum gloeosporioides and Alternaria alternata. Soil microbe Penicillium terrestre at 0–15 cm soil depth showed significant association with pathogens O. erysiphoides and C. gloeosporioides. Soil microbes at 15–30 cm soil depth had no significant influence on occurrence of plant pathogens.

Simultaneous transcriptome analysis of oil palm clones and Phytophthora palmivora reveals oil palm defense strategies.

Phytophthora palmivora is an oomycete that causes oil palm bud rot disease. To understand the molecular mechanisms of this disease, palm clones with contrasting responses (Ortet 34, resistant and Ortet 57, susceptible) were inoculated with P. palmivora, and RNAseq gene expression analysis was performed. The transcriptome was obtained by sequencing using Illumina HiSeq2500 technology during the asymptomatic phase (24, 72 and 120 hours postinfection, hpi). A simultaneous analysis of differentially expressed gene (DEG) profiles in palm and P. palmivora was carried out. Additionally, Gene Ontology (GO) and gene network analysis revealed differences in the transcriptional profile of the two ortets, where a high specificity of the pathogen to colonize the susceptible ortet was found. The transcriptional analysis provided an overview of the genes involved in the recognition and signaling of this pathosystem, where different transcription factors, phytohormones, proteins associated with cell wall hardening and nitrogen metabolism contribute to the resistance of oil palm to P. palmivora. This research provides a description of the molecular response of oil palm to P. palmivora, thus becoming an important source of molecular markers for the study of genotypes resistant to bud rot disease.

Pathogenicity of Malaysian Phytophthora palmivora on cocoa, durian, rubber and oil palm determines the threat of bud rot disease

AbstractThe epidemic of bud rot disease affecting oil palm in Colombia is primarily caused by Phytophthora palmivora. The pathogen has a cosmopolitan presence that includes Southeast Asia, but to date, bud rot has not been reported in this region. This study provides an overview of the potential risk of Malaysian P. palmivora isolates cross‐infecting other host species, including cocoa, durian, rubber and Malaysian oil palm planting materials (Dura × Pisifera, D × P). On cocoa pods, the durian isolate PP7 caused dark brown necrotic lesions. Detached leaf bioassays showed that P. palmivora isolates PP3 and PP7 infected different hosts, except rubber foliage without wounding. Inoculation tests on cocoa, durian and rubber seedlings caused brown necrotic lesions when stems were wounded, with 10% mortality in cocoa and durian at 17 days post‐inoculation (dpi). However, no further infection was observed, and lesions closed within 14–28 dpi on the non‐wounded seedlings. Pathogenicity tests of oil palm seedlings inoculated with isolates PP3 and PP7 indicated that Malaysian P. palmivora isolates were not pathogenic to oil palms based on localized infection observed only through wounding. Overall, the work demonstrated that Malaysian P. palmivora isolates were able to cross‐infect multiple hosts but did not show severe infections on oil palms.

Pseudomonas chlororaphis CP07 strain reduces disease severity caused by Phytophthora palmivora in genotypes of Theobroma cacao

Black pod rot is the most important disease affecting Theobroma cacao in Cuba. Plant growth promoting bacteria (PGPB) are considered an alternative for controlling plant disease in the context of the integrated management. The present work was aimed to evaluate Pseudomonas chlororaphis strain CP07, isolated from T. cacao rhizosphere, as potential PGPB against P. palmivora in cacao plants cultivated under controlled conditions. Three genotypes of Cuban traditional cacao of the group Trinitario and the genotype UF 677 were used. The effect of CP07 was evaluated by using detached leaf tests and in planta assays with plants obtained in vitro from both seeds and micrografting. Inoculation of P. palmivora in control plants showed that genotypes EICB-371, EICB-384 and UF 677 were highly susceptible to the disease (71.4 to 99% disease severity) while EICB-385 was significantly less susceptible (39 to 54.5%). In EICB-371 and EICB-385 genotypes, disease symptoms were significantly reduced in presence of CP07 compared to the control plants in all assays. In contrast, for EICB-384 and UF 677 genotypes, there was not reduction of disease severity in plants pre-treated with CP07. Results show the protective effect of treating cacao plants with CP07 against P. palmivora. Plant genotype significantly influenced the protective ability of bacteria affecting the CP07-mediated disease control. Results suggest that depending on cacao genotype, CP07 has a potential for inducing plant defense against P. palmivora which can be used in the control of black pod rot.