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The rubber tree (Hevea brasiliensis) is vulnerable to infections by various fungal pathogens. White root disease infection is one of the most prevalent diseases of rubber in Malaysia. This disease is caused by the fungus Rigidoporus microporus. Delayed management of this disease can cause considerable reduction in total tree stand and ultimately decreased land productivity. The utilisation of elicitor proteins to heighten host plant resistance represents a sustainable approach to disease control by reducing the use of chemical fungicides. The cerato-platanin protein family is the most widely reported class of elicitor proteins. This study isolated a member of the cerato-platanin family from R. microporus and evaluated its expression during H. brasiliensis infection. Total RNA was extracted from the mycelial sample of R. microporus followed by cDNA synthesis, isolation and cloning of the cerato-platanin transcript referred to as rmcp. In silico characterisation of the obtained sequence was then conducted and the relative expression of the gene was evaluated using RT-qPCR. A transcript of 438 bp encoding 145 amino acids protein, denoted as RmCP, was isolated and cloned. RmCP is composed of a cerato-platanin domain and a predicted N-terminal signal peptide. Phylogenetic analysis grouped RmCP into a cluster together with cerato-platanin proteins originating from basidiomycetes. The expression of rmcp gene was consistent throughout the study period and was not significantly different from axenic culture. This suggests the gene to have a fundamental function in the life cycle of R. microporus. [ABSTRACT FROM AUTHOR]

In today's fast-shifting climate change scenario, crops are exposed to environmental pressures, abiotic and biotic stress. Hence, these will affect the production of agricultural products and give rise to a worldwide economic crisis. The increase in world population has exacerbated the situation with increasing food demand. The use of chemical agents is no longer recommended due to adverse effects towards the environment and health. Biocontrol agents (BCAs) and biostimulants, are feasible options for dealing with yield losses induced by plant stresses, which are becoming more intense due to climate change. BCAs and biostimulants have been recommended due to their dual action in reducing both stresses simultaneously. Although protection against biotic stresses falls outside the generally accepted definition of biostimulant, some microbial and non-microbial biostimulants possess the biocontrol function, which helps reduce biotic pressure on crops. The application of synergisms using BCAs and biostimulants to control crop stresses is rarely explored. Currently, a combined application using both agents offer a great alternative to increase the yield and growth of crops while managing stresses. This article provides an overview of crop stresses and plant stress responses, a general knowledge on synergism, mathematical modelling used for synergy evaluation and type of in vitro and in vivo synergy testing, as well as the application of synergism using BCAs and biostimulants in reducing crop stresses. This review will facilitate an understanding of the combined effect of both agents on improving crop yield and growth and reducing stress while also providing an eco-friendly alternative to agroecosystems. [ABSTRACT FROM AUTHOR]

Background: The basidiomycete fungus, Ganoderma boninense is the main contributor to oil palm Basal Stem Rot (BSR) in Malaysia and Indonesia. Lanosterol 14α-Demethylase (ERG11) is a key enzyme involved in biosynthesis of ergosterol, which is an important component in the fungal cell membrane. The Azole group fungicides are effective against pathogenic fungi including G. boninense by inhibiting the ERG11 activity. However, the work on molecular characterization of G. boninense ERG11 is still unavailable today. Methods and results: This study aimed to isolate and characterize the full-length cDNA encoding ERG11 from G. boninense. The G. boninense ERG11 gene expression during interaction with oil palm was also studied. A full-length 1860 bp cDNA encoding ERG11 was successfully isolated from G. boninense. The G. boninense ERG11 shared 91% similarity to ERG11 from other basidiomycete fungi. The protein structure homology modeling of GbERG11 was analyzed using the SWISS-MODEL workspace. Southern blot and genome data analyses showed that there is only a single copy of ERG11 gene in the G. boninense genome. Based on the in-vitro inoculation study, the ERG11 gene expression in G. boninense has shown almost 2-fold upregulation with the presence of oil palm. Conclusion: This study provided molecular information and characterization study on the G. boninense ERG11 and this knowledge could be used to design effective control measures to tackle the BSR disease of oil palm. [ABSTRACT FROM AUTHOR]

Rice brown spot (BS) exerts devastating agronomic effects on grain quality and overall productivity. In Peninsular Malaysia, BS disease incidence is fairly prevalent and little is known about the diversity of BS pathogens in the local granaries. Fifteen isolates from BS symptomatic rice plants were identified at five different rice granaries across Peninsular Malaysia. Based on the morphological and molecular analyses, two isolates were confirmed as Bipolaris oryzae while the rest were identified as Exserohilum rostratum. Phylogenetic tree analysis revealed that BS incidence in rice granaries in Peninsular Malaysia is caused by a pair of closely related fungal pathogens, E. rostratum and B. oryzae, with the former being more predominant. Cultural characterization of E. rostratum isolate KT831962 showed the best growth and sporulation activity on corn meal agar plates incubated in complete darkness. The effects of calcium silicate (CaSiO3) and rice husk ash (RHA) soil amendment against MR219 and MR253 rice varieties were evaluated during rice-E. rostratum interaction. Results showed that soil amelioration using CaSiO3 and RHA singly and in combination with manganese (Mn) significantly reduced rice BS disease severity. The BS disease index was reduced significantly to less than 31.6% in the silicon-treated rice plants relative to the control plants at 41.2%. Likewise, the grain yield at the harvest stage showed significantly higher yield in the Si-treated rice plants in comparison to the control, non-Si treated rice plants. The findings highlight the potential of RHA agro-waste as Si fertilizer in a sustainable rice production system. [ABSTRACT FROM AUTHOR]

Microbial agents present in soil rhizosphere play a key role in reducing intensive use of inorganic fertilizers, which cause environmental pollution and negatively affect soil fertility. To improve plant growth, microbial agents with silicon (Si) can be used in combination with chemical fertilizers. In this glasshouse study, co-inoculants Enterobacter sp. UPMSSB7, mycorrhizae (Glomus mosseae) and addition of Si were evaluated for growth improvement of rubber seedlings. Results of this study indicated that co-inoculation significantly (P < 0.01) improved stem height, chlorophyll content, leaf area, root and shoot dry weight, total root length, root surface area, and root volume as compared to control treatment. The co-inoculation significantly (P < 0.01) increased Si content in shoot and root as well as leaf nutrients content (N, P, and K) as compared to control treatment. Si alone had no effect on seedling growth and nutrients content. The population of Enterobacter sp. UPMSSB7 in rhizosphere of seedlings as a result of co-inoculation, was not significantly different from Enterobacter sp. UPMSSB7 with Si treatment. The mycorrhizae root colonization and spore density were significantly (P < 0.01) increased in co-inoculation, compared to control and single inoculations with Si. Thus, our results suggested that co-inoculants Enterobacter sp. and mycorrhizae could be an eco-friendly approach for growth promotion of rubber seedlings. [ABSTRACT FROM AUTHOR]

Basal stem rot (BSR) of oil palm is a disastrous disease caused by a white-rot fungus Ganoderma boninense Pat. Non-ribosomal peptides (NRPs) synthesized by non-ribosomal peptide synthetases (NRPSs) are a group of secondary metabolites that act as fungal virulent factors during pathogenesis in the host. In this study, we aimed to isolate NRPS gene of G. boninense strain UPMGB001 and investigate the role of this gene during G. boninense-oil palm interaction. The isolated NRPS DNA fragment of 8322 bp was used to predict the putative peptide sequence of different domains and showed similarity with G. sinense (85%) at conserved motifs of three main NRPS domains. Phylogenetic analysis of NRPS peptide sequences demonstrated that NRPS of G. boninense belongs to the type VI siderophore family. The roots of 6-month-old oil palm seedlings were artificially inoculated for studying NRPS gene expression and disease severity in the greenhouse. The correlation between high disease severity (50%) and high expression (67-fold) of G. boninense NRPS gene at 4 months after inoculation and above indicated that this gene played a significant role in the advancement of BSR disease. Overall, these findings increase our knowledge on the gene structure of NRPS in G. boninense and its involvement in BSR pathogenesis as an effector gene. [ABSTRACT FROM AUTHOR]

The basidiomycete fungus, Ganoderma boninense, has been identified as the main causal agent of oil palm basal stem rot (BSR) disease which has caused significant economic losses to the industry especially in Malaysia and Indonesia. Various efforts have been initiated to understand the disease and this plant pathogen especially at the molecular level. This is the first study of its kind on the development of a polyethylene glycol (PEG)–mediated protoplast transformation system for G. boninense. Based on the minimal inhibitory concentration study, 60 µg/mL and above of hygromycin were effective to completely inhibit G. boninense growth. Approximately 5.145 × 107 cells/mL of protoplasts with the viability of 97.24% was successfully obtained from G. boninense mycelium tissue. The PEG-mediated G. boninense protoplast transformation using 1 µg of transformation vector, 25% of PEG solution, 10 min of pre-transformation incubation, and 30 min of post-transformation incubation has improved the transformation rate as compared with the previous reported protocols for other basidiomycete fungi. Optimization of four transformation parameters has improved the transformation efficiency of G. boninense from an average of 2 to 67 putative transformants. The presence of hygromycin phosphotransferase (hpt) and enhanced green fluorescent protein (eGFP) genes in the putative transformants was detected by PCR and verified by gene sequence analysis. Southern hybridization result further confirmed the integration of hpt gene in G. boninense transformants, and the green fluorescent signal was detected in the G. boninense transformants under the microscopic analysis. The establishment of this transformation system will accelerate the gene function studies of G. boninense especially those genes that may contribute to the pathogenesis of this fungus in oil palm. [ABSTRACT FROM AUTHOR]

The global agricultural direct yield loss is estimated up to 40% and minimizing such loss is therefore crucial for future sustainability of global crop production. The discovery of RNA-mediated gene silencing mechanism has improved our understanding on gene expression and their regulation. The mechanism was later found applicable for controlling various plant pathogens. Recent discoveries indicated that plant small RNAs are involved in plant defence not only against viruses but also extended to other pathogens, such as insect pests and fungi. This finding showed that RNA-mediated gene silencing is a conserved strategy employed by plant as a defence mechanism and will boost the application of RNA-mediated gene silencing to improve crop resistance against various pests and diseases. This review provided summaries of the application of RNA-mediated gene silencing in the plant protection against various pests and diseases including from nematodes, insects, fungi, and viruses. The strategies used and significant findings were also discussed and this information can be considered for future planning of similar study. This review also provided the latest trends and potential applications of dsRNA via non-transgenic approach to control pests and diseases, namely spray-induced gene silencing. The advantages and disadvantages of application of RNA-mediated gene silencing in plant protection via transgenic and non-transgenic approaches were also discussed. The application of RNA-mediated gene silencing could offer a promising solution for plant protection against pests and diseases. [ABSTRACT FROM AUTHOR]

Rigidoporus microporus is a causal agent of white root rot disease of rubber trees. Chemical control is commonly used against this disease but it is expensive, causes environmental pollution and fungal resistance. Silicon is a beneficial element which enhances plant growth and disease resistance but mostly present in insoluble forms. Silicate solubilizing bacteria (SSB) can solubilize the insoluble forms of silicates. This study aimed to screen and evaluate potential SSB with solubilizing activity, plant growth promoting traits and antagonistic activity against R. microporus. Bacteria were isolated from healthy rubber plantation area. Five out of 26 bacterial isolates which showed the ability to solubilize silicate on magnesium trisilicate media were screened in vitro for growth promoting traits and production of indole-3-acetic acid (IAA), siderophores and hydrolytic enzymes. The investigation of antagonistic activity against R. microporus was conducted using dual culture test. The potential SSB isolates were identified by 16S rRNA gene sequencing. The isolate UPMSSB7 showed the highest solubilization of silicate, phosphate (P) and potassium (K) (solubilizing index 4.67, 2.52 and 2.61, respectively). It also showed highest silicate solubilization at 5 and 10 days (9.76 and 11.55 mg L−1, respectively) in liquid assay. It strongly inhibited the growth of R. microporus with percent inhibition of radial growth of 57.24% and produced highest IAA (19.96 µg mL−1). All the isolates produced siderophores. Two isolates, UPMSSB7 and UPMSSB10, were able to secrete cellulase enzyme, but pectinase was produced by UPMSSB7 only. The isolate UPMSSB7 was identified as Enterobacter sp. This isolate was found to be the most potent antagonistic isolate against R. microporus and simultaneously the most efficient one in solubilizing insoluble silicates, as well as P and K. [ABSTRACT FROM AUTHOR]

In contrast, the smallholders, are not seeing the same margins as the downstream sector the latex product makers. To stimulate the increment latex yield in the mature rubber trees, Huan, Xiuhan, Congcong, Huicha, and Jiaquan performed ethephon treatment and observed the increased latex production in the stem while simultaneously studying the physiological responses of rubber leaves in terms of photosynthetic rate, sugar and starch content as well as sugar metabolism. The COVID-19 pandemic has cast the spotlight on the rubber industry on the downstream latex players such as glove makers, which have seen a surge in demand for their products. [Extracted from the article]

African oil palm ( Elaeis guineensis) is an important oil bearing tree commercially cultivated in Malaysia. Palm oil is an important product for local consumption, provides enormous socio-economic benefits of trade and employment opportunities, and fulfilling the growing global demand for vegetable oils. The monoculture system has fostered the outbreak of basal stem rot (BSR) disease caused by the fungus Ganoderma boninense. Quantitative real-time PCR (qRT-PCR) is a widely used molecular technique to examine the infection effect on gene expression in oil palm. The selection of appropriate reference genes is vital for accurate data normalization. In this study, the expression stability of six housekeeping genes- β-actin, cyclophilin, GAPDH, MSD, NAD and ubiquitin were validated in oil palm root tissue after fungal infection. NormFinder and BestKeeper algorithms were used to cross-validate the expression stability of the candidate reference genes. MSD, NAD and ubiquitin were shown to exhibit the highest expression stability. These genes were recommended as reference genes for gene expression studies of oil palm root tissue at early fungal infection stage. [ABSTRACT FROM AUTHOR]

EgT2RIP is a type 2 ribosome-inactivating protein isolated from oil palm ( Elaeis guineensis Jacq.). Its transcript abundance was reported to be up-regulated in oil palm roots upon inoculation of pathogenic fungus Ganoderma boninense in a recent study. This study aims to produce an active recombinant EgT2RIP protein for biological studies. The DNA fragments encoding Chain A (CA) and Chain B (CB) of EgT2RIP were cloned individually in an expression vector. Soluble CA and partially soluble CB were expressed in Escherichia coli Rosetta-gami 2 (DE3). Purified recombinant CA and CB were associated in a cysteine/cystine reduced/oxidized system, yielding a heterodimer protein (AB). The AB protein showed growth inhibitory activity against breast cancer cell lines (MCF-7) as well as non-tumorigenic breast epithelial cell line (MCF-10A) at IC = 1.4 and 10.9 μg mL, respectively. The active protein produced from this study may have the potential to be used for treatment in medical and agricultural fields. [ABSTRACT FROM AUTHOR]

The first record of Ganoderma can be traced back to the Pharmacopoeia written by Chinese scientists in first century B.C. Several Ganoderma species are known as 'white rot' fungi, which cause the display of the white cellulose on wood by degrading the lignin component. Ganoderma boninense is the main agent of basal stem rot (BSR) disease, as a persistent problem in the oil palm ( Elaeis guineensis, Jacq.) cultivation that needs to be controlled. Oil palm, which is the main host of this pathogen, is an economically important crop grown in Southeast Asia, Africa, and America. Due to the negative effects of Ganoderma on the plants, especially on oil palm, this review focuses on the mechanisms of Ganoderma infection and its control, the importance of lignin and silicon (Si) to plant defense. This review also explores different methods for Ganoderma control and techniques for producing less susceptible oil palm. Genetic manipulation of oil palm for enhancing resistance to Ganoderma is also discussed. [ABSTRACT FROM AUTHOR]

Stemphylium lycopersici (Enjoji) W. Yamam was initially described from tomato and has been reported to infect different hosts worldwide. Sequence analyses of the internal transcribed spacer (ITS) regions 1 and 2, including 5.8S rDNA (ITS-5.8S rDNA) and glyceraldehyde-3-phosphate dehydrogenase ( gpd) gene, random amplified polymorphic DNA (RAPD) and inter-simple sequence repeat (ISSR), as well as virulence studies were conducted to analyze 46 S. lycopersici isolates. Stemphylium lycopersici isolates used in this study were obtained from diseased tomato ( Solanum lycopersicum L.), eggplant ( Solanum melongena L.), pepper ( Capsicum annuum L.) and lettuce ( Lactuca sativa L.) from major vegetable growing regions of Malaysia, including the three states of Pahang, Johor and Selangor between 2011 and 2012. Phylogenetic analysis of a combined dataset of the ITS-5.8S rDNA and gpd regions indicated that all isolates were clustered in the sub-cluster that comprised S. lycopersici, and were distinguished from other Stemphylium species. Cluster analyses using the UPGMA method for both RAPD and ISSR markers grouped S. lycopersici isolates into three main clusters with similarity index values of 67 and 68 %. The genetic diversity data confirmed that isolates of S. lycopersici are in concordance to host plants, and not geographical origin of the isolates. All S. lycopersici isolates were pathogenic on their original host plants and showed leaf spot symptoms; however, virulence variability was observed among the isolates. In cross-inoculation assays, the representative isolates were able to cause leaf spot symptoms on eggplant, pepper, lettuce and tomato, but not on cabbage. [ABSTRACT FROM AUTHOR]

Pseudomonas aeruginosa developed its biocontrol agent property through the production of antifungal derivatives, with the phenazine among them. In this study, the applications of crude phenazine synthesized by Pseudomonas aeruginosa UPMP3 and hexaconazole were comparatively evaluated for their effectiveness to suppress basal stem rot infection in artificially G. boninense-challenged oil palm seedlings. A glasshouse experiment under the randomized completely block design was set with the following treatments: non-inoculated seedlings, G. boninense inoculated seedlings, G. boninense inoculated seedlings with 1 mg/ml phenazine application, G. boninense inoculated seedlings with 2 mg/ml phenazine application and G. boninense inoculated seedlings with 0.048 mg/ml hexaconazole application. Seedlings were screened for disease parameters and plant vigour traits (plant height, plant fresh weight, root fresh, and dry weight, stem diameter, and total chlorophyll) at 1-to-4 month post-inoculation (mpi). The application of 2 mg/ml phenazine significantly reduced disease severity (DS) at 44% in comparison to fungicide application (DS = 67%). Plant vigour improved from 1 to 4 mpi and the rate of disease reduction in seedlings with phenazine application (2 mg/ml) was twofold greater than hexaconazole. At 4, 6 and 8 wpi, an up-regulation of chitinase and β-1,3 glucanase genes in seedlings treated with phenazine suggests the involvement of induced resistance in G. boninense-oil palm pathosystem. [ABSTRACT FROM AUTHOR]