First Report of Neopestalotiopsis clavispora causing Leaf Spot on Coconut Seedling in Malaysia.

Coconut (Cocos nucifera) is a high economic value cash crop in Malaysia. In December 2021, irregular spots with dotted rust-like appearance were observed mainly on the tip of the leaves of MATAG variety coconut seedlings at the nursery in Perak state. More than 90% of the coconut seedlings surveyed were infected with leaf spot symptoms. These symptoms could bring huge economic losses due to the downgrade value of the seedlings. 15 symptomatic leaves were obtained from the nursery, 10 mm2 of cut leaves were disinfected with 10% sodium hypochlorite for 10 minutes and rinsed with sterile distilled water before plated on potato dextrose agar (PDA). A total of 4 single-spore isolates were obtained and were observed morphologically. The isolates had white cotton-like appearance with undulate edge. Black acervuli were seen after 7 days of incubation at 26 °C. The conidia were fusiform and contained five cells with four septate and three versicolor cells in between the apical and basal cell. The conidia were 17.2 µm long and 5.9 µm wide (n=30). Conidia consisted of two to three apical appendages and one basal appendage. These morphological characters were consistent with the original description of Neopestalotiopsis clavispora (Santos et al., 2019; Abbas et al., 2022). Species identification was done by amplifying internal transcribed spacer (ITS) region using primers ITS 4 and ITS 5 (White et al., 1990) and beta-tubulin (TUB2) using primers Bt2a and Bt2b (Glass & Donaldson et al., 1995) of the representative isolate LKR1, then sequenced. The 488 bp ITS and 409 bp TUB2 sequences were deposited in GenBank under the accession numbers ON844193 and OP004810, respectively. Isolate LKR1 shares 99.8% identity with the ITS sequence (MH860736.1) of the reference pathogenic N. clavispora strain CBS:447.73 and 100% identity with the TUB2 sequence (KM199443.1) of the reference pathogenic N. clavispora strain CBS 447.73. The phylogenetic analysis confirmed that the isolate LKR1 belonged to N. clavispora when a supported clade is formed with 98% and 94% bootstrap support for ITS and TUB2 respectively with other related N. clavispora. Pathogenicity test was conducted by using five replicates of 8 month old seedlings, they were incubated under greenhouse condition and were watered daily. The leaves of the seedlings were injured with sterile needles and were sprayed with conidial suspension (1 x 10^6 conidia/ml). The control plants were also injured but sprayed with sterile distilled water. After a month, signature symptoms of spots on the leaves appear but none on the control seedling. N. clavispora was successfully re-isolated only from the inoculated symptomatic leaves and identified morphologically. No fungus was re-isolated from the control seedlings. The result was consistent even after repeating the test one more time. N. clavispora has been reported causing leaf spot on Macadamia integrifolia (Santos et al., 2019), Phoenix dactylifera L. (Basavand et al., 2020) and Musa acuminata (Qi et al., 2022). N. clavispora has also been reported causing rust-like appearance of leaves on strawberry (Fragaria × ananassa Duch.) (Obregón et al., 2018). To our knowledge, this is the first report of N. clavispora causing leaf spot disease on coconut seedlings in Malaysia. Through the identification of N. clavispora as the causal agent of leaf spot on coconut, this can help coconut growers to tackle the disease problem earlier thus, preventing the disease from spreading until the adult phase.

Synergism: biocontrol agents and biostimulants in reducing abiotic and biotic stresses in crop.

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.

Identification of drought responsive Elaeis guineensis WRKY transcription factors with sensitivity to other abiotic stresses and hormone treatments.

BACKGROUND: The ability of plants to withstand and thrive in an adverse environment is crucial to ensure their survivability and yield performance. The WRKY transcription factors (TFs) have crucial roles in plant growth, development and stress response, particularly drought stress. In oil palm, drought is recognized as one of the major yield limiting factors. However, the roles of WRKY TFs in the drought response of oil palm is unclear. RESULTS: Herein, we studied the transcriptome of drought treated oil palm leaf and identified 40 differentially expressed genes (DEGs) of WRKY TFs, of which 32 DEGs were upregulated and 8 DEGs were downregulated in response to drought stress in oil palm. They were categorized into Groups I to IV based on the numbers of WRKY domain and the structural difference in the zinc finger domain. Multiple stress- and hormone-responsive cis-regulatory elements were detected in the drought responsive oil palm EgWRKY (Dro-EgWRKY) genes. Fourteen of the 15 selected oil palm WRKY (EgWRKY) genes demonstrated a tissue-specific expression profile except for EgWRKY28 (Group I), which was expressed in all tissues tested. The expression levels of 15 candidate EgWRKYs were upregulated upon salinity and heat treatments, while several genes were also inducible by abscisic acid, methyl jasmonate, salicylic acid and hydrogen peroxide treatments. Members of the Group III WRKY TFs including EgWRKY07, 26, 40, 52, 59, 73 and 81 displayed multiple roles in drought- and salinity-response under the modulation of phytohormones. CONCLUSIONS: EgWRKY TFs of oil palm are involved in phytohormones and abiotic stress responses including drought, salinity and heat. EgWRKY07, 26, 59 and 81 from Group III maybe important regulators in modulating responses of different abiotic stresses. Further functional analysis is required to understand the underlying mechanism of WRKY TFs in the regulatory network of drought stress.

Comparative genomics reveals differences in algal galactan biosynthesis and related pathways in early and late diverging red algae.

Red algae are a major source of marine sulfated galactans. In this study, orthologs and inparalogs from seven red algae were analyzed and compared with the aim to discover differences in algal galactan biosynthesis and related pathways of these algae. Red algal orthologs for putative carbohydrate sulfotransferases were found to be prevalent in Porphyridium purpureum, Florideophytes and Bangiophytes, while red algal orthologs for putative chondroitin sulfate synthases, sulfurylases, and porphyranases /carrageenases were found exclusively in Florideophytes and Bangiophytes. The acquirement of these genes could have happened after the divergence from Cyanidiales red algae. Cyanidiales red algae were found to have more number and types of putative sulfate permeases, suggesting that these genes could have been acquired in adaptation to the environmental stresses and biogeochemistry of respective habitats. The findings of this study shed lights on the evolution of different homeostasis mechanisms by the early and late diverging red algal orders.

EgRBP42 from oil palm enhances adaptation to stress in Arabidopsis through regulation of nucleocytoplasmic transport of stress-responsive mRNAs.

Abiotic stress reduces plant growth and crop productivity. However, the mechanism underlying posttranscriptional regulations of stress response remains elusive. Herein, we report the posttranscriptional mechanism of nucleocytoplasmic RNA transport of stress-responsive transcripts mediated by EgRBP42, a heterogeneous nuclear ribonucleoprotein-like RNA-binding protein from oil palm, which could be necessary for rapid protein translation to confer abiotic stress tolerance in plants. Transgenic Arabidopsis overexpressing EgRBP42 showed early flowering through alteration of gene expression of flowering regulators and exhibited tolerance towards heat, cold, drought, flood, and salinity stresses with enhanced poststress recovery response by increasing the expression of its target stress-responsive genes. EgRBP42 harbours nucleocytoplasmic shuttling activity mediated by the nuclear localization signal and the M9-like domain of EgRBP42 and interacts directly with regulators in the nucleus, membrane, and the cytoplasm. EgRBP42 regulates the nucleocytoplasmic RNA transport of target stress-responsive transcripts through direct binding to their AG-rich motifs. Additionally, EgRBP42 transcript and protein induction by environmental stimuli are regulated at the transcriptional and posttranscriptional levels. Taken together, the posttranscriptional regulation of RNA transport mediated by EgRBP42 may change the stress-responsive protein profiles under abiotic stress conditions leading to a better adaptation of plants to environmental changes.

Unraveling the nuclear and chloroplast genomes of an agar producing red macroalga, Gracilaria changii (Rhodophyta, Gracilariales).

Agar and agarose have wide applications in food and pharmaceutical industries. Knowledge on the genome of red seaweeds that produce them is still lacking. To fill the gap in genome analyses of these red algae, we have sequenced the nuclear and organellar genomes of an agarophyte, Gracilaria changii. The partial nuclear genome sequence of G. changii has a total length of 35.8Mb with 10,912 predicted protein coding sequences. Only 39.4% predicted proteins were found to have significant matches to protein sequences in SwissProt. The chloroplast genome of G. changii is 183,855bp with a total of 201 open reading frames (ORFs), 29 tRNAs and 3 rRNAs predicted. Five genes: ssrA, leuC and leuD CP76_p173 (orf139) and pbsA were absent in the chloroplast genome of G. changii. The genome information is valuable in accelerating functional studies of individual genes and resolving evolutionary relationship of red seaweeds.

Isolation and Characterization of Lactobacillus spp. from Kefir Samples in Malaysia.

Kefir is a homemade, natural fermented product comprised of a probiotic bacteria and yeast complex. Kefir consumption has been associated with many advantageous properties to general health, including as an antioxidative, anti-obesity, anti-inflammatory, anti-microbial, and anti-tumor moiety. This beverage is commonly found and consumed by people in the United States of America, China, France, Brazil, and Japan. Recently, the consumption of kefir has been popularized in other countries including Malaysia. The microflora in kefir from different countries differs due to variations in culture conditions and the starter media. Thus, this study was aimed at isolating and characterizing the lactic acid bacteria that are predominant in Malaysian kefir grains via macroscopic examination and 16S ribosomal RNA gene sequencing. The results revealed that the Malaysian kefir grains are dominated by three different strains of Lactobacillus strains, which are Lactobacillus harbinensis, Lactobacillusparacasei, and Lactobacillus plantarum. The probiotic properties of these strains, such as acid and bile salt tolerances, adherence ability to the intestinal mucosa, antibiotic resistance, and hemolytic test, were subsequently conducted and extensively studied. The isolated Lactobacillus spp. from kefir H maintained its survival rate within 3 h of incubation at pH 3 and pH 4 at 98.0 ± 3.3% and 96.1 ± 1.7% of bacteria growth and exhibited the highest survival at bile salt condition at 0.3% and 0.5%. The same isolate also showed high adherence ability to intestinal cells at 96.3 ± 0.01%, has antibiotic resistance towards ampicillin, penicillin, and tetracycline, and showed no hemolytic activity. In addition, the results of antioxidant activity tests demonstrated that isolated Lactobacillus spp. from kefir G possessed high antioxidant activities for total phenolic content (TPC), total flavonoid content (TFC), ferric reducing ability of plasma (FRAP), and 1,1-diphenyl-2-picryl-hydrazine (DPPH) assay compared to other isolates. From these data, all Lactobacillus spp. isolated from Malaysian kefir serve as promising candidates for probiotics foods and beverage since they exhibit potential probiotic properties and antioxidant activities.

De novo transcriptome analyses of host-fungal interactions in oil palm (Elaeis guineensis Jacq.).

BACKGROUND: Basal stem rot (BSR) is a fungal disease in oil palm (Elaeis guineensis Jacq.) which is caused by hemibiotrophic white rot fungi belonging to the Ganoderma genus. Molecular responses of oil palm to these pathogens are not well known although this information is crucial to strategize effective measures to eradicate BSR. In order to elucidate the molecular interactions between oil palm and G. boninense and its biocontrol fungus Trichoderma harzianum, we compared the root transcriptomes of untreated oil palm seedlings with those inoculated with G. boninense and T. harzianum, respectively. RESULTS: Differential gene expression analyses revealed that jasmonate (JA) and salicylate (SA) may act in an antagonistic manner in affecting the hormone biosynthesis, signaling, and downstream defense responses in G. boninense-treated oil palm roots. In addition, G. boninense may compete with the host to control disease symptom through the transcriptional regulation of ethylene (ET) biosynthesis, reactive oxygen species (ROS) production and scavenging. The strengthening of host cell walls and production of pathogenesis-related proteins as well as antifungal secondary metabolites in host plants, are among the important defense mechanisms deployed by oil palm against G. boninense. Meanwhile, endophytic T. harzianum was shown to improve the of nutrition status and nutrient transportation in host plants. CONCLUSION: The findings of this analysis have enhanced our understanding on the molecular interactions of G. boninense and oil palm, and also the biocontrol mechanisms involving T. harzianum, thus contributing to future formulations of better strategies for prevention and treatment of BSR.

Flavokawain B induced cytotoxicity in two breast cancer cell lines, MCF-7 and MDA-MB231 and inhibited the metastatic potential of MDA-MB231 via the regulation of several tyrosine kinases In vitro.

BACKGROUND: The kava-kava plant (Piper methysticum) is traditionally consumed by the pacific islanders and has been linked to be involved in several biological activities. Flavokawain B is a unique chalcone, which can be found in the roots of the kava-kava plant. In this study, the operational mechanism of the anti-cancer activity of a synthetic Flavokawain B (FKB) on two breast cancer cell lines, MCF-7 and MDA-MB231 was investigated. METHOD: Several in vitro assays were attempted such as MTT, flow cytometry of cell cycle analysis, annexin V analysis, and JC-1 analysis to detect apoptosis. Moreover, in vitro metastasis assays were also performed such as transwell migration assay, invasion assay, rat aorta ring and HUVEC tube formation. Molecular analysis of related genes and proteins were conducted using real-time PCR and proteome profiler analysis. RESULTS: Based on our results, apoptosis was induced when both MCF-7 and MDA-MB231 were treated with FKB. A significant G2/M arrest was seen in MDA-MB231 cells. Additionally, FKB also inhibited the in vitro migration and invasion in MDA-MB231 cells in a dose dependent manner. Moreover, FKB can be a potential inhibitor in angiogenesis as it suppressed the formation of vessels in HUVEC cells as well as in the ex-vivo rat aortic ring assay. CONCLUSION: Our findings suggested that FKB also regulated several receptor tyrosine kinases. Overall, FKB is not only a potential candidate to be an anti-cancer agent, but as an anti-metastatic agent as well.

Vitamin C suppresses cell death in MCF-7 human breast cancer cells induced by tamoxifen.

Vitamin C is generally thought to enhance immunity and is widely taken as a supplement especially during cancer treatment. Tamoxifen (TAM) has both cytostatic and cytotoxic properties for breast cancer. TAM engaged mitochondrial oestrogen receptor beta in MCF-7 cells and induces apoptosis by activation of pro-caspase-8 followed by downstream events, including an increase in reactive oxygen species and the release of pro-apoptotic factors from the mitochondria. In addition to that, TAM binds with high affinity to the microsomal anti-oestrogen-binding site and inhibits cholesterol esterification at therapeutic doses. This study aimed to investigate the role of vitamin C in TAM-mediated apoptosis. Cells were loaded with vitamin C by exposure to dehydroascorbic acid, thereby circumventing in vitro artefacts associated with the poor transport and pro-oxidant effects of ascorbic acid. Pre-treatment with vitamin C caused a dose-dependent attenuation of cytotoxicity, as measured by acridine-orange/propidium iodide (AO/PI) and Annexin V assay after treatment with TAM. Vitamin C dose-dependently protected cancer cells against lipid peroxidation caused by TAM treatment. By real-time PCR analysis, an impressive increase in FasL and tumour necrosis factor-α (TNF-α) mRNA was detected after TAM treatment. In addition, a decrease in mitochondrial transmembrane potential was observed. These results support the hypothesis that vitamin C supplementation during cancer treatment may detrimentally affect therapeutic response.

Anti-Diabetic Effect of Lactobacillus Paracasei Isolated from Malaysian Water Kefir Grains.

The prevalence of type 2 diabetes mellitus (T2DM) is alarming because it is always linked to the increase in chronic diseases, mortality, and socioeconomic burden. Water kefir has a wide range of functional and probiotic characteristics attributed to the microorganisms present in the kefir grains. The present study aims to evaluate the in vivo anti-diabetic potential of the isolated Lactobacillus paracasei from Malaysian water kefir grains (MWKG) which was reported to have excellent probiotic properties and high antioxidant activities as reported previously. High-fat diet/streptozotocin (HFD/STZ) induction was used to obtain a T2DM model followed by treatment with the isolated L. paracasei from MWKG. The levels of glucose, insulin, and in vivo liver antioxidants were quantified after 14 weeks. Gene expression analysis of the liver was also carried out using microarray analysis, and several genes were selected for validation using quantitative real-time PCR. Insulin tolerance test demonstrated that the L. paracasei isolated from the MWKG alleviated T2DM by improving the area under the curve of the insulin tolerance test whereby low-dose and high-dose concentrations treated groups showed 2424.50 ± 437.02 mmol/L·min and 2017.50 ± 347.09 mmol/L·min, respectively, compared to untreated diabetic mice which was 3884.50 ± 39.36 mmol/L·min. Additionally, treatment with the isolated L. paracasei from MWKG regulated the expression of several genes related to glucose homeostasis and lipid metabolism in diabetic mice. These results suggested that the isolated L. paracasei from MWKG could be a potential dietary supplement for T2DM.

Functional characterization of the MSP-C6 promoter as a potential tool for mesocarp-preferential expression of transgenes.

Modification of lipid composition in the mesocarp tissue of oil palm involves genetic manipulation of multiple genes. More than one mesocarp-preferential promoter is necessary for the expression of individual transgenes in the same plant to obviate transcriptional gene silencing. This study aimed to identify genes that are preferentially expressed in the mesocarp tissue and characterize selected candidate mesocarp-preferential promoters. Ten transcripts that were preferentially expressed in the mesocarp tissue were identified from the analysis of 82 transcriptome datasets of 12 different oil palm tissues. The expression of two candidate genes, MSP-C1 and MSP-C6, was verified to be preferentially expressed in the mesocarp tissues and shown to have a low expression level in non-mesocarp tissues by reverse transcription quantitative real-time PCR (RT-qPCR). MSP-C6 promoter fragments of different lengths were transformed into tomato plants for further characterization. Both unripe and ripe fruits of transgenic tomato plants transformed with a construct harboring the MSP-C6-F1 (2014 bp) promoter were shown to have high beta-glucuronidase (GUS) activities. The findings of this study suggest the potential applications of the MSP-C6 promoter as a molecular tool for genetic engineering of novel traits in fruit crops.

Isolation and characterization of two ABRE-binding proteins: EABF and EABF1 from the oil palm.

Abscisic acid (ABA) is an important phytohormone involved in the abiotic stress resistance in plants. The ABA-responsive element (ABRE) binding factors play significant roles in the plant development and response to abiotic stresses, but none so far have been isolated and characterized from the oil palm. Two ABA-responsive cDNA clones, named EABF and EABF1, were isolated from the oil palm fruits using yeast one-hybrid system. The EABF had a conserved AP2/EREBP DNA-binding domain (DNA-BD) and a potential nuclear localization sequence (NLS). No previously known DNA-BD was identified from the EABF1 sequence. The EABF and EABF1 proteins were classified as DREB/CBF and bZIP family members based on the multiple sequence alignment and phylogenetic analysis. Both proteins showed ABRE-binding and transcriptional activation properties in yeast. Furthermore, both proteins were able to trans-activate the down-stream expression of the LacZ reporter gene in yeast. An electrophoretic mobility shift assay revealed that in addition to the ABRE sequence, both proteins could bind to the DRE sequence as well. Transcriptional analysis revealed that the expression of EABF was induced in response to the ABA in the oil palm fruits and leaves, but not in roots, while the EABF1 was constitutively induced in all tissues. The expressions of both genes were strongly induced in fruits in response to the ABA, ethylene, methyl jasmonate, drought, cold and high-salinity treatments, indicating that the EABF and EABF1 might act as connectors among different stress signal transduction pathways. Our results indicate that the EABF and EABF1 are novel stress-responsive transcription factors, which are involved in the abiotic stress response and ABA signaling in the oil palm and could be used for production of stress-tolerant transgenic crops.

EgRBP42 encoding an hnRNP-like RNA-binding protein from Elaeis guineensis Jacq. is responsive to abiotic stresses.

RNA-binding proteins (RBPs) have been implicated as regulatory proteins involved in the post-transcriptional processes of gene expression in plants under various stress conditions. In this study, we report the cloning and characterization of a gene, designated as EgRBP42, encoding a member of the plant heterogeneous nuclear ribonucleoprotein (hnRNP)-like RBP family from oil palm (Elaeis guineensis Jacq.). EgRBP42 consists of two N-terminal RNA recognition motifs and a glycine-rich domain at the C-terminus. The upstream region of EgRBP42 has multiple light-responsive, stress-responsive regulatory elements and regulatory elements associated with flower development. Real-time RT-PCR analysis of EgRBP42 showed that EgRBP42 was expressed in oil palm tissues tested, including leaf, shoot apical meristem, root, female inflorescence, male inflorescence and mesocarp with the lowest transcript level in the roots. EgRBP42 protein interacted with transcripts associated with transcription, translation and stress responses using pull-down assay and electrophoretic mobility shift assay. The accumulation of EgRBP42 and its interacting transcripts were induced by abiotic stresses, including salinity, drought, submergence, cold and heat stresses in leaf discs. Collectively, the data suggested that EgRBP42 is a RBP, which responds to various abiotic stresses and could be advantageous for oil palm under stress conditions. Key message EgRBP42 may be involved in the post-transcriptional regulation of stress-related genes important for plant stress response and adaptation.

Hepatoprotective Activity of Elephantopus scaber on Alcohol-Induced Liver Damage in Mice.

Elephantopus scaber has been traditionally used as liver tonic. However, the protective effect of E. scaber on ethanol-induced liver damage is still unclear. In this study, we have compared the in vivo hepatoprotective effect of E. scaber with Phyllanthus niruri on the ethanol-induced liver damage in mice. The total phenolic and total flavanoid content of E. scaber ethanol extract were determined in this study. Accelerating serum biochemical profiles (including AST, ALT, ALP, triglyceride, and total bilirubin) associated with fat drop and necrotic body in the liver section were observed in the mice treated with ethanol. Low concentration of E. scaber was able to reduce serum biochemical profiles and the fat accumulation in the liver. Furthermore, high concentration of E. scaber and positive control P. niruri were able to revert the liver damage, which is comparable to the normal control. Added to this, E. scaber did not possess any oral acute toxicity on mice. These results suggest the potential effect of this extract as a hepatoprotective agent towards-ethanol induced liver damage without any oral acute toxicity effect. These activities might be contributed, or at least in part, by its high total phenolic and flavonoid contents.

mRNA expression of EgCHI1, EgCHI2, and EgCHI3 in oil palm leaves (Elaeis guineesis Jacq.) after treatment with Ganoderma boninense pat. and Trichoderma harzianum Rifai.

BACKGROUND: Basal stem rot (BSR) disease caused by the fungus Ganoderma boninense is the most serious disease affecting the oil palm; this is because the disease escapes the early disease detection. The biocontrol agent Trichoderma harzianum can protect the disease only at the early stage of the disease. In the present study, the expression levels of three oil palm (Elaeis guineensis Jacq.) chitinases encoding EgCHI1, EgCHI2, and EgCHI3 at 2, 5, and 8 weeks inoculation were measured in oil palm leaves from plants treated with G. boninense or T. harzianum alone or both. METHODS: The five-month-old oil palm seedlings were treated with Gano-wood blocks inoculum and trichomulch. Expression of EgCHI1, EgCHI2, and EgCHI3 in treated leaves tissue was determined by real-time PCR. RESULTS: Oil palm chitinases were not strongly expressed in oil palm leaves of plants treated with G. boninense alone compared to other treatments. Throughout the 8-week experiment, expression of EgCHI1 increased more than 3-fold in leaves of plants treated with T. harzianum and G. boninense when compared to those of control and other treated plants. CONCLUSION: The data illustrated that chitinase cDNA expression varied depending on tissue and the type of treatment.

Ecological and evolutionary diversification of sulphated polysaccharides in diverse photosynthetic lineages: A review.

Sulphated polysaccharides (SPs) are carbohydrate macromolecules with sulphate esters that are found among marine algae, seagrasses, mangroves and some terrestrial plants. The sulphate concentration in the ocean (28 mM) since ancient time could have driven the production of SPs in marine algae. SPs have a gelatinous property that can protect marine algae against desiccation and salinity stress. Agar and carrageenan are red algal SPs that are widely used as gelling agents in the food and pharmaceutical industries. The information on the SPs from freshwater and land plants are limited. In this review, we reviewed the taxonomic distribution and composition of SPs in different photosynthetic lineages, and explored the association of SP production in these diversified photosynthetic organisms with evolution history and environmental stresses. We also reviewed the genes/proteins involved in SP biosynthesis. Insights into SP biosynthetic machinery may shed light on the evolution that accompanied adaptation to life on earth.

Identification of non-ribosomal peptide synthetase in Ganoderma boninense Pat. that was expressed during the interaction with oil palm.

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.

Comparative transcriptome analysis reveals novel insights into transcriptional responses to phosphorus starvation in oil palm (Elaeis guineensis) root.

BACKGROUND: Phosphorus (P), in its orthophosphate form (Pi) is an essential macronutrient for oil palm early growth development in which Pi deficiency could later on be reflected in lower biomass production. Application of phosphate rock, a non-renewable resource has been the common practice to increase Pi accessibility and maintain crop productivity in Malaysia. However, high fixation rate of Pi in the native acidic tropical soils has led to excessive utilization of P fertilizers. This has caused serious environmental pollutions and cost increment. Even so, the Pi deficiency response mechanism in oil palm as one of the basic prerequisites for crop improvement remains largely unknown. RESULTS: Using total RNA extracted from young roots as template, we performed a comparative transcriptome analysis on oil palm responding to 14d and 28d of Pi deprivation treatment and under adequate Pi supply. By using Illumina HiSeq4000 platform, RNA-Seq analysis was successfully conducted on 12 paired-end RNA-Seq libraries and generated more than 1.2 billion of clean reads in total. Transcript abundance estimated by fragments per kilobase per million fragments (FPKM) and differential expression analysis revealed 36 and 252 genes that are differentially regulated in Pi-starved roots at 14d and 28d, respectively. Genes possibly involved in regulating Pi homeostasis, nutrient uptake and transport, hormonal signaling and gene transcription were found among the differentially expressed genes. CONCLUSIONS: Our results showed that the molecular response mechanism underlying Pi starvation in oil palm is complexed and involved multilevel regulation of various sensing and signaling components. This contribution would generate valuable genomic resources in the effort to develop oil palm planting materials that possess Pi-use efficient trait through molecular manipulation and breeding programs.

The oil palm metallothionein promoter contains a novel AGTTAGG motif conferring its fruit-specific expression and is inducible by abiotic factors.

The 1,053-bp promoter of the oil palm metallothionein gene (so-called MSP1) and its 5' deletions were fused to the GUS reporter gene, and analysed in transiently transformed oil palm tissues. The full length promoter showed sevenfold higher activity in the mesocarp than in leaves and 1.5-fold more activity than the CaMV35S promoter in the mesocarp. The 1,053-bp region containing the 5' untranslated region (UTR) gave the highest activity in the mesocarp, while the 148-bp region was required for minimal promoter activity. Two positive regulatory regions were identified at nucleotides (nt) -953 to -619 and -420 to -256 regions. Fine-tune deletion of the -619 to -420 nt region led to the identification of a 21-bp negative regulatory sequence in the -598 to -577 nt region, which is involved in mesocarp-specific expression. Gel mobility shift assay revealed a strong interaction of the leaf nuclear extract with the 21-bp region. An AGTTAGG core-sequence within this region was identified as a novel negative regulatory element controlling fruit-specificity of the MSP1 promoter. Abscisic acid (ABA) and copper (Cu(2+)) induced the activity of the promoter and its 5' deletions more effectively than methyl jasmonate (MeJa) and ethylene. In the mesocarp, the full length promoter showed stronger inducibility in response to ABA and Cu(2+) than its 5' deletions, while in leaves, the -420 nt fragment was the most inducible by ABA and Cu(2+). These results suggest that the MSP1 promoter and its regulatory regions are potentially useful for engineering fruit-specific and inducible gene expression in oil palm.