ITS-PCR-RFLP analysis of Ganoderma sp. infecting industrial crops

Ganoderma is a disastrous pathogen that has been causing tremendous losses to economically important crops in many countries. Vast genetic variations have been observed among several Ganoderma species, even from the same host. In this study, genetic variation was assessed among 44 isolates of Ganoderma sp. isolated from the basidiocarps of four different hosts (oil palm, rubber, tea, and forest trees) collected from selected areas of Peninsular Malaysia. Restriction Fragment Length Polymorphism (RFLP) technique, using ITS1 and ITS4 primers, was used to amplify Internal Transcribed Spacer (ITS) regions. Amplified products were further digested using Bsu 151, Hind III and Taq I restriction enzymes. Cluster analysis with UPGMA using genetic distances clustered all the isolates studied into four main groups. Generally, Ganoderma isolates from the same host were clustered together. The isolates from tea and rubber were more closely related compared to oil palm and forest trees. Similarly, the Ganoderma isolates from the same host were also clustered together, and three species were identified, namely, G. boninense (from oil palm and coconut stumps), G. philippii (rubber) and G. australe (forest trees). The results obtained from the analysis showed that host preference was a possible factor in the differentiation of Ganoderma species

Fungi associated with the blighted leaf symptoms of Hevea brasiliensis in Malaysia

This article describes the fungi isolated from the blighted leaf of rubber (Hevea brasiliensis) tree in Malaysia. Previously, Neofusicoccum ribis (Family Botryosphaeriaceae) was reported as the causal agent of rubber leaf blight in Malaysia. To date, there are limited studies on this particular disease in Malaysia and worldwide. The current study was carried out on rubber leaves displaying leaf blight symptoms caused by N. ribis from different locations to discover the fungi that reside in the blighted leaves. Rubber leaf samples with blight symptoms were collected from two different locations in Malaysia. The fungal isolates were isolated following the agar plate method and subjected to cultural and morphological characterization. Based on the cultural and morphological characterization, eight fungal isolates were further subjected to molecular identification. Five fungal isolates namely SBI, SB2, SB3, SB6 and SPKT1 were identified as N. ribis, one fungus (SB4) as Diaporthe drenthii, and another two fungi namely SB5 and SPKT2 were identified as Lasiodiplodia pseudotheobromae. Based on the morphological and molecular identification, all the N. ribis isolates demonstrated similar characteristics of the rubber leaf blight pathogen as documented in a previous study

Proficiency of biocontrol agents as plant growth promoters and hydrolytic enzyme producers in Ganoderma boninense infected oil palm seedlings

Basal stem rot (BSR) is a major disease encountered by Malaysian oil palm caused by Ganoderma species. Pseudomonas aeruginosa has been shown to improve plant growth and is classified as a Plant Growth Promoter Bacterium (PGPB) while Trichoderma species has been reported as the most common biocontrol agents (BCAs) of oil palm rhizosphere. Therefore, based on preliminary trials P. aeruginosa (UPM P3) and Trichoderma asperellum (UPM29) were selected as BCAs to control Ganoderma infection in oil palm. Both BCAs were screened for their antagonistic properties against G. boninense (UPM13), plant growth promoting traits and enzymatic activities. The result of dual culture test demonstrated that P. aeruginosa and T. asperellum were able to inhibit G. boninense growth with the percentage of inhibition radial growth (PIRG) values of 71.42% and 76.85%, respectively. Besides that, both showed positive results for phosphate solubilizing activity and indole acetic acid (IAA) production. However for siderophore production test, only T. asperellum exhibited positive siderophore production. These BCAs were also tested for their ability inproducing hydrolytic enzymes such as chitinase, cellulose, and 1, 3, β-glucanase

Antagonistic efficacy of Trichoderma harzianum and Bacillus cereus against Ganoderma disease of oil palm via dip, place and drench (DPD) artificial inoculation technique

Sustainability of the oil palm industry is crucial to ensure Malaysia's gross domestic product (GDP) by the agricultural sector. It is crucial to discover a sustainable and eco-friendly remedy for the most devastating Ganoderma disease of oil palm. The effects of pre-inoculation of oil palm seedlings with either Trichoderma harzianum and/or Bacillus cereus on their vegetative growth and the suppression of Ganoderma boninense were investigated. The dip, place and drench (DPD) artificial inoculation method was used to assure disease development. Disease severity was assessed based on the root symptoms (DS), disease incidence (DI) and disease reduction (DR). Application of a mixture of T. harzianum and B. cereus had the highest contribution to the vegetative growth of oil palm seedlings. However, single application of B. cereus was found to be the most effective treatment in suppressing Ganoderma disease of oil palm with a disease reduction of 94.75% followed by single applications of T. harzianum (78.98%) and mixture of both T. harzianum and B. cereus (68.49%)

Relationship between Ganoderma ergosterol concentration and Basal stem rot disease progress on Elaeis guineensis

Basal stem rot (BSR) is a devastating disease to Malaysian oil palm. Current techniques employed for BSR disease detection on oil palm are laborious, time consuming, costly, and subjected to accuracy limitations. An ergosterol detection method was developed, whereby it correlated well with the degree of infection in oil palm. This current study was designed to study the relationship between Ganoderma biomass, ergosterol concentration, BSR disease progress and to validate the efficiency of microwave assisted extraction (MAE) method for extraction of ergosterol compound. In addition, testing on the sensitivity of thin layer chromatography (TLC) analysis for detection of ergosterol was also the aim of this study. The optimised procedure involved extracting a small amount of Ganoderma-infected oil palm root tissues suspended in low volumes of solvent followed by irradiation in a conventional microwave oven at 70°C and medium high power for 30 s, resulting in simultaneous extraction and saponification. Based on the results obtained, MAE method may be effective in extracting low to high yields of ergosterol from infected oil palm roots demonstrating disease scale 2, 3 and 4. Positive relationship was observed between ergosterol content and inoculation period starting day 3 in the inoculated oil palm seedlings and hour 6 in germinated seeds. TLC analysis demonstrated a good correlation with high performance liquid chromatography (HPLC) quantification. Therefore, a semi-quantitative TLC analysis may be applied for handling a large amount of samples during onset field survey

Significant oil palm diseases impeding global industry : a review

Oil palm is the most well-known high yielding and versatile oil crop grown. In 2019, Malaysia ranked as the world’s second largest producer of palm oil products (28%) after Indonesia (57%), contributing around USD 9.07 billion to the country’s Gross Domestic Product (GDP) and has been the main economic contributor in the agriculture sector. In recent years, increase in demand has paralleled production. However, pests and diseases have been the major constraints in production causing reduction in palm oil quality and yield. This paper reviews a current status of oil palm diseases of significant economic importance affecting the global oil palm industry. Plant diseases such as basal stem rot (BSR), Fusarium wilt, Phytophthora bud rot, Pestalotiopsis leaf spot, common spear rot, orange spotting and upper stem rot (USR) have been classified as the major diseases of oil palm in terms of economic importance. This paper discusses on the damages caused by the diseases, the causal pathogens and pathogenicity, symptoms as well as treatments or control in the view of developing measures to manage occurrences

First report on the fungal pathogens associated with leaf tip blight of oil palm at nursery stage in Malaysia

Oil palm has been contributing to the economic growth and gross national income (GNI) of Malaysia. On that note, supply of disease-free oil palm seedlings to field is crucial. At present many nurseries encounter disease infestations of the seedlings at nursery stages. One of the most common diseases identified was leaf tip blight. The disease incidences cause critical quality, quantity loss of the seedlings and draw other pathogens in the field to infect the initially infected host. Till to date, no study has been conducted to diagnose leaf tip blight disease of oil palm at nursery stage in Malaysia. Molecular identification was conducted by using 3 specific primers namely actin gene (ACT), β-tubulin-2 (Bt2), glyceraldehyde-3-phosphate dehydrogenase (GD) gene and complete rDNA-ITS (ITS) to confirm the isolates. All the isolated fungi matched 98% to 100% similarity with GenBank database. Thus, the isolated isolates were identified as Nigrosporasp., Colletotrichumgloeosporioides andPhoma sp. In vitro pathogenicity test demonstrated that,the three-isolates produced similar leaf tip blight symptoms as the infested seedlings at the nursery. As a conclusion, Nigrosporasp., C. gloeosporioidesand Phomasp.were identified as the causal pathogen of leaf tip blight of oil palm with different levels of virulence

Morphological and molecular characterization of fungal pathogen, Magnaphorthe oryzae

Rice is arguably the most crucial food crops supplying quarter of calories intake. Fungal pathogen, Magnaphorthe oryzae promotes blast disease unconditionally to gramineous host including rice species. This disease spurred an outbreaks and constant threat to cereal production. Global rice yield declining almost 10-30% including Malaysia. As Magnaphorthe oryzae and its host is model in disease plant study, the rice blast pathosystem has been the subject of intense interest to overcome the importance of the disease to world agriculture. Therefore, in this study, our prime objective was to isolate samples of Magnaphorthe oryzae from diseased leaf obtained from MARDI Seberang Perai, Penang, Malaysia. Molecular identification was performed by sequences analysis from internal transcribed spacer (ITS) region of nuclear ribosomal RNA genes. Phylogenetic affiliation of the isolated samples were analyzed by comparing the ITS sequences with those deposited in the GenBank database. The sequence of the isolate demonstrated at least 99% nucleotide identity with the corresponding sequence in GenBank for Magnaphorthe oryzae. Morphological observed under microscope demonstrated that the structure of conidia followed similar characteristic as M. oryzae. Finding in this study provide useful information for breeding programs, epidemiology studies and improved disease management

Assessment of Variability and Genetic Diversity Study in an Advanced Segregating Population in Rice with Blast Resistance Genes Introgression

Blast disease caused by a pathogenic fungus, Magnaphorthe oryzae, is the most destructive disease and has resulted in more than 50% of crop losses worldwide, including in Malaysia. The present study was conducted to investigate genetic variability among 36 advanced lines of MR264 × PS2 rice with blast resistance genes introduced at the Faculty of Applied Sciences, Universiti Teknologi MARA, Malaysia. Traits such as days of maturity, plant height, grain width, and seed setting rate exhibited negative skewness in this study, indicating a doubling of gene effects. Seed setting rate and 1000 grain weight showed positive kurtosis, indicating gene interactions. The phenotypic coefficient of variation (PCV) was slightly higher than the genotypic coefficient of variation (GCV) for all traits, indicating that environmental influences affect the expression of these traits. High heritability associated with high genetic advance as a percentage of the mean was observed for filled grains per panicle. In addition, the second-highest value for high heritability and the high genetic advance was observed for the number of tillers. Cluster and principal component analysis revealed that 36 advanced lines were grouped into four clusters based on ten agromorphological traits. Clusters A and C had higher mean values for most of the traits studied than clusters B and D. Desirable recombinants for higher yields with a broad genetic base can be generated by using cross lines from different clusters

Cross-infectivity of oil palm by Phytophthora spp. isolated from perennial crops in Malaysia

Bud rot disease or “Pudricion del cogollo” (PC) of oil palm is a major constraint on production in Colombia and neighbouring countries such as Brazil, Costa Rica, Ecuador, Nicaragua, Panama, Peru and Surinam. To date, there are no documented reports of Phytophthora disease of oil palm in South-East Asia. This research, therefore, was conducted to determine the pathogenic potential of Phytophthora palmivora and Phytophthora nicotianae on oil palm using both in vitro and nursery inoculation experiments. In vitro inoculation of both P. palmivora and P. nicotianae on immature oil palm leaflets caused discoloration within 2 days of inoculation and incubation at 25 ± 1.5°C, 100% RH. Similarly, in nursery trials, lesions formed on the buds (unopened leaflets) 3 days after inoculation with P. palmivora or P. nicotianae zoospore suspensions. No lesions developed on untreated leaflets in either in vitro or nursery inoculation experiments. Phytophthora spp. were re-isolated from leaflet lesions and confirmed as the inoculated pathogens