Bud Rot Disease Research Articles

The Dynamic Interaction between Oil Palm and Phytophthora palmivora in Bud Rot Disease: Insights from Transcriptomic Analysis and Network Modelling.

Bud Rot, caused by Phytophthora palmivora, is considered one of the main diseases affecting African oil palm (Elaeis guineensis). In this study, we investigated the in vitro molecular dynamics of the pathogen-host interaction by analyzing gene expression profiles from oil palm genotypes that were either susceptible or resistant to the disease. We observed distinct interactions of P. palmivora with resistant and susceptible oil palms through co-expression network analysis. When interacting with susceptible genotypes, P. palmivora exhibited upregulation of carbohydrate and sulfate transport genes. These genes demonstrated co-expression with apoplastic and cytoplasmic effectors, including cell wall degrading enzymes, elicitins, and RxLR motif effectors. The pathogen manipulated susceptible oil palm materials, exacerbating the response and compromising the phenylpropanoid pathway, ultimately leading to susceptibility. In contrast, resistant materials exhibited control over their response through putative Heat Shock Proteins (HSP) that maintained homeostasis between primary metabolism and biotic defense. Co-expressed genes related to flavonoids, WRKY transcripts, lectin-type receptors, and LRR receptors may play important roles in pathogen control. Overall, the study provides new knowledge of the molecular mechanisms underlying the interaction between E. guineensis and P. palmivora, which can contribute to controlling Bud Rot in oil palms and gives new insights into the interactions of P. palmivora with their hosts.

Cross-pathogenicity of Phytophthora palmivora associated with bud rot disease of oil palm and development of biomarkers for detection.

Phytophthora palmivora has caused disease in many crops including oil palm in the South America region. The pathogen has had a significant economic impact on oil palm cultivation in Colombia, and therefore poses a threat to oil palm cultivation in other regions of the World, especially in Southeast Asia, the largest producer of the crop. This study aimed to look at the ability of isolates from Malaysia, Colombia, and other regions to cross-infect Malaysian oil palm, durian, and cocoa and to develop specific biomarkers and assays for identification, detection, and diagnosis of P. palmivora as a key component for the oil palm biosecurity continuum in order to contain the disease especially at the ports of entry. We have developed specific molecular biomarkers to identify and detect Phytophthora palmivora using polymerase chain reaction (PCR) and real-time loop mediated isothermal amplification (rt-LAMP) in various sample types such as soil and plants. The limit of detection (DNA template, pure culture assay) for the PCR assay is 5.94 × 10-2 ng µl-1 and for rt-LAMP is 9.28 × 10-4 ng µl-1. Diagnosis using rt-LAMP can be achieved within 30min of incubation. In addition, PCR primer pair AV3F/AV3R developed successfully distinguished the Colombian and Malaysian P. palmivora isolates.

Biocontrol agents for Sustainable Management of Bud Rot Disease in Coconut Nursery

Biocontrol agents for Sustainable Management of Bud Rot Disease in Coconut Nursery

Sustainable management of bud rot disease of coconut

Sustainable management of bud rot disease of coconut

The Fungal, Nutritional, and Metabolomic Diagnostics of the Oil Palm Elaeis guineensis Affected by Bud Rot Disease in Esmeraldas, Ecuador.

The oil palm Elaeis guineensis represents one of the most important crops in Ecuador. Considering that bud rot disease is deadly in Ecuador, more attention has been given to identifying possible causes for palm debility from this disease. We studied the involvement of fungi and nutrients in triggering bud rot disease in E. guineensis. Special emphasis was given to the molecules synthesized by the plant to protect against this devastating disease. Techniques like Diagnosis and Recommendation Integrated System (DRIS) and metagenomic analysis were used to understand the possible implications of biotic and abiotic factors in the development of bud rot disease in oil palm in Ecuador. Liquid chromatography-mass spectrometry (LC-MS) analysis was used to identify the phenolic protection barrier of the palm facing the disease. Our results indicate that fungi from Ascomyceta phylum were found in the tested samples. The species directly involved are different in soil compared with plants. The results indicate a deficiency of chemical elements, such as Ca, Mn, Mg, and Fe, which are responsible for palm debility from bud rot disease. More than 30 compounds with protective roles were identified in the leaves of symptomatic plants from the first stage of the infection.

Pest and Disease Challenges, Control Strategies as Well as Policy Support for The IPM Program on Coconut

Coconut played an important role in humans as an estate commodity. Many efforts have been made to increase coconut production through intensification, extensification, and diversification but those efforts have not given maximum results yet, likewise, assembling superior coconut varieties also have been carried out, to produce superior coconut varieties such as Tall coconut, Dwarf coconut, Hybrid coconut, but this is also not been able to increase coconut production optimally. On the other hand, several factors can cause the decline in coconut production, such as severe damage caused by major pests and diseases. The list of highlighted major pests in this article was as follows, Rhynchophorus spp., Cyrtotrachelus sp., Oryctes rhinoceros, Amblypelta sp., and Opisina arenosella. Three species of it were categorized as new emerging pests in Indonesia: Cyrtotrachelus sp., Amblypelta sp., and O. arenosella. Cyrtotrachelus sp. has been reported to cause damage, and mortality of coconut plants reached 10.63%, as well as Amblypelta sp., as reported in North Sulawesi Province, while the O. arenosella has been reported to caused severe damage to coconut plantations in West Java. For diseases, are Bud Rot Disease and Nut Fall Disease caused by Phytophthora palmivora. In 2022, Nias Yellow Dwarf coconuts in Tiniawangko Village, South Minahasa, North Sulawesi, infected with Bud Rot disease by 31.53%, causing coconut plants to die, and Nut Fall Disease causing a decrease in production by 25.00%. In addition, it was found that coconut plants died due to infection with an Unknown Disease. Integrated Pest Management (IPM) is an effective approach to control all pests and diseass, where possible. This is a combination of methods (pesticides, physical controls such as site hygiene, and biological controls) to minimize the use of pesticides and the cost of control. The IPM program can run well if there is policy support from the government.

Variation of the Antioxidative Defense in Elaeis guineensis Jacq. Facing Bud Rot Disease in the Coastal Area of Ecuador.

Elaeis guineensis Jacq. has gained a reputation in the food industry as an incredible crop capable of supplying the world's largest edible oil production. In Ecuador, an important oil palm-producing country, this crop is affected in a high percentage by the bud rot disease, which is responsible for palm death. The main objective of the investigation was dedicated to understanding the palm defense mechanism facing bud rot disease, translated in the induction of reactive oxygen species, activation of defensive machinery comprising enzymatic and non-enzymatic antioxidative components, secondary metabolites, carotenoids accumulation in the palm during all stages of disease infection. For this, a survey was conducted in different oil palm plantations in the Esmeraldas province, one of the most representative for its highest incidence of bud rot disease. The survey completed DPPH, FRAP, ABTS, and other spectrophotometric analyses to underline the biochemical, biological, and physiological palm response front of bud rot incidence. The palm defense strategy in each disease stage could be represented by the phenolic compound's involvement, an increment of antioxidant activity, and the high enzymatic activity of phenylalanine ammonia-lyase (PAL). The results of the investigation made understandable the palm defense strategy front of this disease, respectively, the antioxidative defense and the palm secondary compounds involved.

ADVANCEMENT IN OIL PALM PLANTING MATERIALS IN THE FUTURE

The development of shorter planting materials based on MPOB Nigerian population 12 and E.oleifera x E.guineensis inter-specific hybrids is highlighted in this paper. The progeny test results of Nigerian Population 12 with selected Deli duras showed that the DxP oil yield ranges from 8.1-8.5 tonnes per hectare per year. The height increment of DxP is 33-39 cm per year. In comparison, the height increment of Deli x AVROS is about 60 cm per annum. In Colombia where DxP commercial plantations are devastated by bud rot disease, Cinepalma demonstrated that application of naphthalene acetic acid (NAA) increased the oil yield of inter-specific hybrids which are tolerant to the disease. It was demonstrated in commercial plantations that applying NAA can produce more than 40 tonnes fresh fruit bunch (FFB) per hectare per year, with an extraction rate of about 27 per cent giving >10 tonnes oleic oil per hectare. The tissue culture labs in Kuala Lumpur-Kepong (KLK) and Asian Agri are also cloning their elite Deli duras and pisiferas to create semi- and bi- seeds. Applied Agricultural Resources (AAR) is the largest semi-clonal seed producer in Malaysia, and produces about 8 million per year and sells the seeds at a premium. A number of plantation companies in Malaysia and Indonesia have initiated programmes to produce Ganoderma tolerant planting material. Companies have adopted an integrated disease management (IDM) approach, covering land preparation, planting tolerant varieties, use bioagents, early detection, and removal of infected materials. Asian Agri AA TOPAZ GT variety, partially tolerant to Ganoderma, has an average oil yield potential of 9.2 tonnes crude palm oil (CPO) per hectare per year. Digitalisation refers to the process of integrating advanced digital technologies such as artificial intelligence (AI), big data, robotics, unmanned aerial vehicle (UAV), sensors, and communication networks, all connected through Internet of Things (IoT) into farm production system. A major breakthrough was achieved by the oil palm Genome Programme at the Malaysian Palm Oil Board (MPOB), where the identification of the gene controlling Shell has made it possible to identify and differentiate dura, tenera and pisifera at the nursery stage. This led to the first molecular diagnostic assay known as SureSawitTMSHELL, which the breeders can use to identify and isolate dura, tenera and pisifera seedlings from TxT and TxP breeding crosses. The kit can be used for identification of dura and pisifera contaminants in the nursery and more recently at the seed production facility. The planter has an important role to help realise the full potential of planting materials. The planter’s role starts from receipt of germinated seeds to field planting. The planter is assigned to monitor ripeness standard, harvesting, loose fruit collection and managing of workers, all of which are major tasks to ensure productivity. Climate change is real and we have to confront drought and floods more frequently. In order to minimise the impact of drought, it is advisable to plant planting materials with high bunch number. MPOB has collected oil palm germplasm in the dry areas of Nigeria. This germplasm has attributes such as high bunch number, low bunch weight and high chlorophyll content in the leaves. These traits are useful to develop drought tolerant planting materials.

Towards Phytopathogen Diagnostics? Coconut Bud Rot Pathogen Phytophthora palmivora Mycelial Proteome Analysis Informs Genome Annotation.

Planetary agriculture stands to benefit immensely from phytopathogen diagnostics, which would enable early detection of pathogens with harmful effects on crops. For example, Phytophthora palmivora is one of the most destructive phytopathogens affecting many economically important tropical crops such as coconut. P. palmivora causes diseases in over 200 host plants, and notably, the bud rot disease in coconut and oil palm, which is often lethal because it is usually detected at advanced stages of infection. Limited availability of large-scale omics datasets for P. palmivora is an important barrier for progress toward phytopathogen diagnostics. We report here the mycelial proteome of P. palmivora using high-resolution mass spectrometry analysis. We identified 8073 proteins in the mycelium. Gene Ontology-based functional classification of detected proteins revealed 4884, 4981, and 3044 proteins, respectively, with roles in biological processes, molecular functions, and cellular components. Proteins such as P-loop, NTPase, and WD40 domains with key roles in signal transduction pathways were identified. KEGG pathway analysis annotated 2467 proteins to various signaling pathways, such as phosphatidylinositol, Ca2+, and mitogen-activated protein kinase, and autophagy and cell cycle. These molecular substrates might possess vital roles in filamentous growth, sporangia formation, degradation of damaged cellular content, and recycling of nutrients in P. palmivora. This large-scale proteomics data and analyses pave the way for new insights on biology, genome annotation, and vegetative growth of the important plant pathogen P. palmivora. They also can help accelerate research on future phytopathogen diagnostics and preventive interventions.

Coconut’s Bud Rot by Phytophthora palmivora: A Destructive Disease

Phytophthora palmivora (Butler) is a cosmopolitan hemibiotrophic oomycete that may infect over 200 plant species, including cocos nucifera, one of the world’s most valuable crops which is commonly called as Coconut. Coconut is a key economic commodity in India, plays an important role in contributing to India’s GDP of about 15,000 crore rupees and 72% of worlds total production is from India and productivity is also high in India. Bud rot disease caused by Phytophthora palmivora grounds a significant amount of crop loss each year. Phytophthora palmivora infects many parts of the coconut plant including the buds, causing bud rot disease. This review focuses on the overview of Coconut production in India and Phytophthora palmivora infection to bud of coconut plant. We highlight some current findings on the bud rot disease of coconut caused by Phytophthora palmivora. This review examines the identification of Phytophthora palmivora as a cause of bud rot disease of coconut in India, its isolation, inhibition and discuss the importance of Phytophthora palmivora as a major threat to coconut palm plantings globally.

Assessment of the Spatial Distribution and Risk Associated with Fruit Rot Disease in Areca catechu L.

Phytophthora meadii (McRae) is a hemibiotrophic oomycete fungus that infects tender nuts, growing buds, and crown regions, resulting in fruit, bud, and crown rot diseases in arecanut (Areca catechu L.), respectively. Among them, fruit rot disease (FRD) causes serious economic losses that are borne by the growers, making it the greatest yield-limiting factor in arecanut crops. FRD has been known to occur in traditional growing areas since 1910, particularly in Malnad and coastal tracts of Karnataka. Systemic surveys were conducted on the disease several decades ago. The design of appropriate management approaches to curtail the impacts of the disease requires information on the spatial distribution of the risks posed by the disease. In this study, we used exploratory survey data to determine areas that are most at risk. Point pattern (spatial autocorrelation and Ripley’s K function) analyses confirmed the existence of moderate clustering across sampling points and optimized hotspots of FRD were determined. Geospatial techniques such as inverse distance weighting (IDW), ordinary kriging (OK), and indicator kriging (IK) were performed to predict the percent severity rates at unsampled sites. IDW and OK generated identical maps, whereby the FRD severity rates were higher in areas adjacent to the Western Ghats and the seashore. Additionally, IK was used to identify both disease-prone and disease-free areas in Karnataka. After fitting the semivariograms with different models, the exponential model showed the best fit with the semivariogram. Using this model information, OK and IK maps were generated. The identified FRD risk areas in our study, which showed higher disease probability rates (>20%) exceeding the threshold level, need to be monitored with the utmost care to contain and reduce the further spread of the disease in Karnataka.

Physicochemical characterization of bunches and oil composition in a backcross progeny (caiaué x oil palm) x oil palm

Hybrids between caiaué and oil palm (IEH OxG) are explored in genetic improvement with the main objective of associating the high palm oil productivity of oil palm with resistance of caiaué to Bud Rot disease. In addition, caiaué has better oil quality and greater resistance to some pests and diseases than oil palm and these characteristics are transmitted to the hybrid between species. Due to fertility problems, IEH OxG plantations require assisted pollination, which raises the production costs. Backcrossings using oil palm as recurrent parent (BC OGxG) are being evaluated as a solution to restore the fertility of IEH OxG, however, the species contrast to physicochemical characteristics of the bunch and to oil composition, therefore, there is a need to observe how these characteristics vary in BC OGxG. Physicochemical characteristics of the bunch and fatty acid composition of the oil produced by 90 plants from an BC OGxG progeny were analysed. A large variation was observed in the progeny, with mean values of 9.0 kg for bunch weight, 46.0% of parthenocarpic fruits in the bunch weight, 72.2% of mesocarp in normal fruit and 86.5% in parthenocarpic fruit, 37.6% of oil in the humid mesocarp of normal fruits and 35.9% in parthenocarpic fruits and 16.4% of oil content in the freshfruits bunch (FFB). The unsaturated fatty acids oleic (52.5%) and linoleic (10.8%) and the saturated fatty acids palmitic (30.7%) and stearic (4.4 %) stood out in the oil composition. In the progeny BC OGxG is possible to select individuals for high OCB and for a greater or lesser percentage of saturated or unsaturated fatty acids in the oil composition.

Morphological and molecular characterization of an Elaeis oleifera (H.B.K) Cortes germplasm collection located in Ucayali, Peru.

The African oil palm (Elaeis guineensis Jacq) is a crop that is widely distributed in tropical regions around the world; however, this crop is subject to limitations such as rapid trunk growth and susceptibility to bud rot and red ring diseases particularly in South America. To overcome these limitations, national breeding and conservation programs have been established, and there is a need to identify parental palms from natural populations of the American oil palm (E. oleifera H.B.K. Cortes) with desirable yield and morphological traits (i.e., yield production and bunch number) and with high genetic diversity. However, in Peru the morphological and genetic data related to this important crop is limited. In this study, we characterized the morphological and yield and estimated the genetic diversity using 12 neutral microsatellite markers (simple sequence repeats, SSRs) across 72 oil palm individuals belonging to the E. oleifera germplasm collection located in the tropical region of Ucayali, Peru. Our results showed that morphological and yield traits explained approximately 40.39% of the variability within the Peruvian germplasm. Furthermore, Yield Production was highly correlated with two yield traits: Bunch Number (0.67) and Average weight per bunch (0.78). Based on the yield and morphological traits, a clustering analysis was performed and three phenotypic groups were identified (1, 2 and 3) in which groups 1 and 3 showed high scores associated primarily with yield traits. Microsatellite markers revealed 143 alleles, 11.92 ± 4.72 alleles per locus (A) and an expected heterozygosity (He) of 0.69 ± 0.045. A structural analysis identified three populations (k = 3), that were not related to the phenotypic groups. Interestingly, a multiple allele background was identified within the groups using multilocus and phylogenetic relationship analyses. This is the first Peruvian report regarding E. oleifera that shows preliminary data of the morphological and yield traits and genetic data, and highlight the importance of this information to set up future steps to national breeding strategies and improve the conservation of genetic material of E. oleifera. Overall, these novel findings could contribute to the development of the local oil palm industry in Peru.

High-Oleic Palm Oil (HOPO) Production from Parthenocarpic Fruits in Oil Palm Interspecific Hybrids Using Naphthalene Acetic Acid

Interspecific OxG hybrids of African palm Elaeis guineensis Jacq. and the American palm Elaeis oleifera Cortes produce high-oleic palm oil (HOPO) with low saturated fatty acid content. OxG hybrids are highly productive, grow slowly, and are resistant to bud rot disease. However, OxG hybrid pollen presents low viability and germinability, so assisted pollination is a must. Hybrids can produce parthenocarpic or seedless fruits, with the exogenous application of plant growth regulators. Thus, naphthalene acetic acid (NAA) effects on parthenocarpic fruits induction, bunch formation, and oil quality were evaluated. The OxG hybrid Coari x La Mé was used. NAA doses, frequency, number of applications, and the phenological stages for the treatments were defined. A total dose of 1200 mg L−1 NAA applied three or four times produced bunches with better fruit set, similar average bunch weight, and oil to dry mesocarp than those obtained with assisted pollination. At a semi-commercial scale, 1200 mg L−1 NAA induced bunches that consisted of 93% or more of seedless fruits. Bunch number (2208 ± 84 versus 1690 ± 129) and oil to bunch (32.2 ± 0.7 versus 25.3 ± 0.8) were higher in the NAA induced bunches than in the assisted pollination. However, the average bunch weight was lower (12.2 ± 0.4 versus 14.9 ± 0.6). NAA increased oil to bunch in 36% (8.7 ± 0.1 versus 6.4 ± 0.3). Thus, with this technology, it is plausible to reach more than 10 tons per hectare per year of HOPO. Potentially, without increasing the planted oil palm area, OxG hybrids and NAA applications could alone meet the world’s fats and oil demands.

Isolation, Identification and Molecular Characterization of Pathogenic Fungus causing bud Rot Disease to Coconut: Its Inhibition using Silkworm Fecal Matter Mediated Synthesized Silver and Copper Nanoparticles

Coconut is one the major economic crop in India; a considerable amount of crop will be lost every year due to bud rot disease. Phytophthora palmivora is an omnipresent pathogen which causes many different diseases on a wide range of plants including bud rot of coconut. In the present investigation, we have successfully isolated bud rot disease causing fungus from the infected coconut plant samples. The isolated fungus was primarily identified by observing in microscopy further the same sample was sent for molecular identification. The presence of Phytophthora palmivora was confirmed in 18s rRNA sequencing. The growth of isolated fungus was effectively inhibited using biosynthesized Silver and Copper nanoparticles. The inhibition effects of nanoparticles against Phytophthora palmivora were observed excellent in dose-dependent manner. The silver nanoparticles synthesized using Silkworm fecal matter was shown superior inhibition activity towards Phytophthora palmivora compare to standard fungicide Fluconazole. Hence, these silver Nano particles could be successfully used in inhibiting the pathogenic fungus causing bud rot disease to coconut.

Association of the soil insect Scaptocoris minor Berg (Heteroptera, Cydnidae) with foci of bud-rot diseases of oil palm in eastern Ecuador

The bud-rot fatal diseases represent a threat to the economically important oil palm (Elaeis guineensis Jacq.) through all Latin America. The etiology in Ecuador is still unknown. It is assumed that insect transmission of an unknown pathogen is possible but there is a lack of evidence for transmission by an aerial insect. Therefore it was interesting to dedicate some observations to the piercing-sucking insect living on the roots of the oil palm in Eastern Ecuador which had been identified as Scaptocoris sp. The observations took place in the highly affected plantation Palmeras del Ecuador, Sucumbios province, in 1999. Collected specimens on the oil palm roots were identified as Scaptocoris minor Berg (Heteroptera, Cydnidae). S. minor presence on the roots of palms was more frequent inside the bud-rot foci than in less affected areas (borders of the foci and in younger plots without foci). It is important to consider S. minor as a potential vector of bud-rot diseases of the oil palm in Ecuador and it should be tested.

Development of a system based on aerial images for the morphological patterns classification using support vector machine

Oil palm cultivation is one of the major agricultural activities in Colombia. Production performance is related to the good practices in the plantation, mainly regarding the management of phytosanitary conditions. Bud rot disease is the one with the greatest impact in Colombia. The most commonly used technique for its detection is from routine visual inspection on each palm, being costly and inefficient. For this reason, the aim of this study is the development of a classification algorithm based on binary support vector machines for the detection of Bud Rot. The model was obtained from 798 aerial images acquired by unmanned aerial vehicles. Each image was tagged by an expert palm grower based on the presence or absence of the disease. These images were described by 531 morphological features extracted using the concatenation of uniform binary local pattern vectors. Bootstrapping was used to balance the classes, obtaining 507 observations per class. To evaluate the performance metrics of the classifier, an 8-fold Monte Carlo cross-validation was implemented by randomly splitting the data set into training (80%), validation (10%), and test (10%) sets with balanced classes. Finally, the model achieved a performance greater than 96.0%. This indicates that the model developed could be a great technique to automate bud rot detection with high reliability, increasing the efficiency in the recognition. All these thanks to the fusion of Machine Learning techniques with the phenomena of optical physics.

Generating the Baseline in the Early Detection of Bud Rot and Red Ring Disease in Oil Palms by Geospatial Technologies

Oil palm cultivation in Ecuador is important for the agricultural sector. As a result of it, the country generates sources of employment in some of the most vulnerable zones; it contributes 0.89% of the gross domestic product and 4.35% of the agricultural gross domestic product. In 2017, a value of USD $252 million was generated by exports, and palm contributed 4.53% of the agricultural gross domestic product (GDP). It is estimated that 125,000 hectares of palm were lost in the Republic of Ecuador due to Red Ring Disease (RRD) and specifically Bud Rot (BR). The current study aimed to generate an early detection of BR and RRD in oil palm. Image acquisition has been performed using Remotely Piloted Aircraft System (RPAS) with Red, Green, and Blue (RGB) cannons, and multispectral cameras, in study areas with and without the presence of the given disease. Hereby, we proposed two phases. In phase A, a drone flight has been conducted for processing and georeferencing. This allowed to obtain an orthomosaic that serves as input for obtaining several vegetation indices of the healthy crop. The data and products obtained from this phase served as a baseline to perform comparisons with plantations affected by BR and RRD and to differentiate the palm varieties that are used by palm growers. In phase B, the same process has been applied three times with an interval of 15 days in an affected plot, in order to identify the symptoms and the progress of them. A validation for the diseases detection has been performed in the field, by taking Global Positioning System (GPS) points of the palms that presented symptoms of BR and RRD, through direct observation by field experts. The inputs obtained in each monitoring allowed to analyze the spatial behavior of the diseases. The values of the vegetation indices obtained from Phase A and B aimed to establish the differences between healthy and diseased palms, with the purpose of generating the baseline of early responses of BR and RRD conditions. However, the best vegetation index to detect the BR was the Visible Atmospherically Resistant Index (VARI).

Genomic Variability of Phytophthora palmivora Isolates from Different Oil Palm Cultivation Regions in Colombia.

Palm oil is the most consumed vegetable oil globally, and Colombia is the largest palm oil producer in South America and fourth worldwide. However, oil palm plantations in Colombia are affected by bud rot disease caused by the oomycete Phytophthora palmivora, leading to significant economic losses. Infection processes by plant pathogens involve the secretion of effector molecules, which alter the functioning or structure of host cells. Current long-read sequencing technologies provide the information needed to produce high-quality genome assemblies, enabling a comprehensive annotation of effectors. Here, we describe the development of genomic resources for P. palmivora, including a high-quality genome assembly based on long and short-read sequencing data, intraspecies variability for 12 isolates from different oil palm cultivation regions in Colombia, and a catalog of over 1,000 candidate effector proteins. A total of 45,416 genes were annotated from the new genome assembled in 2,322 contigs adding to 165.5 Mbp, which represents an improvement of two times more gene models, 33 times better contiguity, and 11 times less fragmentation compared with currently available genomic resources for the species. Analysis of nucleotide evolution in paralogs suggests a recent whole-genome duplication event. Genetic differences were identified among isolates showing variable virulence levels. We expect that these novel genomic resources contribute to the characterization of the species and the understanding of the interaction of P. palmivora with oil palm and could be further exploited as tools for the development of effective strategies for disease control.

RESPON EMPAT KELAPA HIBRIDA HARAPAN TERHADAP PENYAKIT BUSUK PUCUK DAN GUGUR BUAH

<p><strong>Response of four new coconut hybrids to bud rot and premature nutfull diseases</strong></p><p>The objective of Ihe experiment was to find out Ihe resistance of four new coconut hybrids GRA x DMT. GKB x DMT, GKN x DTE. GKB x DTE against bud rol and premature nutfall diseases due lo Phytophthora palmivora. The field observation on bud rot was conducted in coconut trial plots at Kima Atas experimental garden. Minahasa District, North Sulawesi Province for 4 years (1995-1998). The field trial was arranged in a randomized block design with 6 treatments (4 coconut hybrids. 2 control) and 60 replicates The experiment under laboratory condilion was conducted to know the artificial infection development of P palmivora on coconut nut The experiment was arranged in a completely randomized design with 6 treatments (4 coconut hybrids, 2 control) and 10 replicates. The result of the field observation showed that percentage of coconut infection by bud rot per cultivar were PB-121 (23.33%) as the highest and then followed by GKN x DTE (8.33%), KHINA-1 (5.0%) and GKB x DMT (3.33%) while cultivars of GKB x DTE and GRA x DMT unlil 4 years observation were not infected by bud rot In laboratory trial, Ihe growth rate of pathogen was very high on KHINA-1 (12.62 mm2/day). The growth rate of pathogen in GKB x DIE and GRA x DMT were slowest (8 9 mm'/day) while those in PB- 121, GKN x Dll and GKB x DMT were moderate (9-10.2 mm2/day).</p>