Displaying publications 61 - 80 of 109 in total

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  1. Fulltext Genetic diversity of Pantoea stewartii subspecies stewartii causing jackfruit-bronzing disease in Malaysia
    Abidin N, Ismail SI, Vadamalai G, Yusof MT, Hakiman M, Karam DS, et al.
    PLoS One, 2020;15(6):e0234350.
    PMID: 32530926 DOI: 10.1371/journal.pone.0234350
    Jackfruit-bronzing is caused by bacteria Pantoea stewartii subspecies stewartii (P. stewartii subsp. stewartii), showing symptoms of yellowish-orange to reddish discolouration and rusty specks on pulps and rags of jackfruit. Twenty-eight pure bacterial strains were collected from four different jackfruit outbreak collection areas in Peninsular Malaysia (Jenderam, Maran, Muadzam Shah and Ipoh). Positive P. stewartii subsp. stewartii verification obtained in the study was based on the phenotypic, hypersensitivity, pathogenicity and molecular tests. Multilocus sequence analysis (MLSA) was performed using four housekeeping genes (gyrB, rpoB, atpD and infB) on all 28 bacterial strains. Single gyrB, rpoB, atpD and infB phylogenetic trees analyses revealed the bootstrap value of 99-100% between our bacterial strains with P. stewartii subsp. stewartii reference strains and P. stewartii subsp. indologenes reference strains. On the other hand, phylogenetic tree of the concatenated sequences of the four housekeeping genes revealed that our 28 bacterial strains were more closely related to P. stewartii subsp. stewartii (99% similarities) compared to its close relative P. stewartii subsp. indologenes, although sequence similarity between these two subspecies were up to 100%. All the strains collected from the four collection areas clustered together, pointing to no variation among the bacterial strains. This study improves our understanding and provided new insight on the genetic diversity of P. stewartii subsp. stewartii associated with jackfruit-bronzing in Malaysia.
    Matched MeSH terms: Plant Diseases/microbiology*
  2. Fulltext Analysis of the leaf transcriptome of Musa acuminata during interaction with Mycosphaerella musicola: gene assembly, annotation and marker development
    Passos MA, de Cruz VO, Emediato FL, de Teixeira CC, Azevedo VC, Brasileiro AC, et al.
    BMC Genomics, 2013 Feb 05;14:78.
    PMID: 23379821 DOI: 10.1186/1471-2164-14-78
    BACKGROUND: Although banana (Musa sp.) is an important edible crop, contributing towards poverty alleviation and food security, limited transcriptome datasets are available for use in accelerated molecular-based breeding in this genus. 454 GS-FLX Titanium technology was employed to determine the sequence of gene transcripts in genotypes of Musa acuminata ssp. burmannicoides Calcutta 4 and M. acuminata subgroup Cavendish cv. Grande Naine, contrasting in resistance to the fungal pathogen Mycosphaerella musicola, causal organism of Sigatoka leaf spot disease. To enrich for transcripts under biotic stress responses, full length-enriched cDNA libraries were prepared from whole plant leaf materials, both uninfected and artificially challenged with pathogen conidiospores.

    RESULTS: The study generated 846,762 high quality sequence reads, with an average length of 334 bp and totalling 283 Mbp. De novo assembly generated 36,384 and 35,269 unigene sequences for M. acuminata Calcutta 4 and Cavendish Grande Naine, respectively. A total of 64.4% of the unigenes were annotated through Basic Local Alignment Search Tool (BLAST) similarity analyses against public databases.Assembled sequences were functionally mapped to Gene Ontology (GO) terms, with unigene functions covering a diverse range of molecular functions, biological processes and cellular components. Genes from a number of defense-related pathways were observed in transcripts from each cDNA library. Over 99% of contig unigenes mapped to exon regions in the reference M. acuminata DH Pahang whole genome sequence. A total of 4068 genic-SSR loci were identified in Calcutta 4 and 4095 in Cavendish Grande Naine. A subset of 95 potential defense-related gene-derived simple sequence repeat (SSR) loci were validated for specific amplification and polymorphism across M. acuminata accessions. Fourteen loci were polymorphic, with alleles per polymorphic locus ranging from 3 to 8 and polymorphism information content ranging from 0.34 to 0.82.

    CONCLUSIONS: A large set of unigenes were characterized in this study for both M. acuminata Calcutta 4 and Cavendish Grande Naine, increasing the number of public domain Musa ESTs. This transcriptome is an invaluable resource for furthering our understanding of biological processes elicited during biotic stresses in Musa. Gene-based markers will facilitate molecular breeding strategies, forming the basis of genetic linkage mapping and analysis of quantitative trait loci.

    Matched MeSH terms: Plant Diseases/microbiology
  3. Fulltext Population genomics reveals additive and replacing horizontal gene transfers in the emerging pathogen Dickeya solani
    Khayi S, Blin P, Pédron J, Chong TM, Chan KG, Moumni M, et al.
    BMC Genomics, 2015;16:788.
    PMID: 26467299 DOI: 10.1186/s12864-015-1997-z
    Dickeya solani is an emerging pathogen that causes soft rot and blackleg diseases in several crops including Solanum tuberosum, but little is known about its genomic diversity and evolution.
    Matched MeSH terms: Plant Diseases/microbiology
  4. Morphological and molecular characterization of Fusarium. solani and F. oxysporum associated with crown disease of oil palm
    Hafizi R, Salleh B, Latiffah Z
    Braz J Microbiol, 2013;44(3):959-68.
    PMID: 24516465
    Crown disease (CD) is infecting oil palm in the early stages of the crop development. Previous studies showed that Fusarium species were commonly associated with CD. However, the identity of the species has not been resolved. This study was carried out to identify and characterize through morphological approaches and to determine the genetic diversity of the Fusarium species. 51 isolates (39%) of Fusarium solani and 40 isolates (31%) of Fusarium oxysporum were recovered from oil palm with typical CD symptoms collected from nine states in Malaysia, together with samples from Padang and Medan, Indonesia. Based on morphological characteristics, isolates in both Fusarium species were classified into two distinct morphotypes; Morphotypes I and II. Molecular characterization based on IGS-RFLP analysis produced 27 haplotypes among the F. solani isolates and 33 haplotypes for F. oxysporum isolates, which indicated high levels of intraspecific variations. From UPGMA cluster analysis, the isolates in both Fusarium species were divided into two main clusters with the percentage of similarity from 87% to 100% for F. solani, and 89% to 100% for F. oxysporum isolates, which was in accordance with the Morphotypes I and II. The results of the present study indicated that F. solani and F. oxysporum associated with CD of oil palm in Malaysia and Indonesia were highly variable.
    Matched MeSH terms: Plant Diseases/microbiology*
  5. Application of lemongrass oil in vapour phase for the effective control of anthracnose of 'Sekaki' papaya
    Ali A, Wee Pheng T, Mustafa MA
    J Appl Microbiol, 2015 Jun;118(6):1456-64.
    PMID: 25727701 DOI: 10.1111/jam.12782
    To evaluate the potential use of lemongrass essential oil vapour as an alternative for synthetic fungicides in controlling anthracnose of papaya.
    Matched MeSH terms: Plant Diseases/microbiology*
  6. Rapid detection of Ganoderma-infected oil palms by microwave ergosterol extraction with HPLC and TLC
    Muniroh MS, Sariah M, Zainal Abidin MA, Lima N, Paterson RR
    J Microbiol Methods, 2014 May;100:143-7.
    PMID: 24681306 DOI: 10.1016/j.mimet.2014.03.005
    Detection of basal stem rot (BSR) by Ganoderma of oil palms was based on foliar symptoms and production of basidiomata. Enzyme-Linked Immunosorbent Assays-Polyclonal Antibody (ELISA-PAB) and PCR have been proposed as early detection methods for the disease. These techniques are complex, time consuming and have accuracy limitations. An ergosterol method was developed which correlated well with the degree of infection in oil palms, including samples growing in plantations. However, the method was capable of being optimised. This current study was designed to develop a simpler, more rapid and efficient ergosterol method with utility in the field that involved the use of microwave extraction. The optimised procedure involved extracting a small amount of Ganoderma, or Ganoderma-infected oil palm suspended in low volumes of solvent followed by irradiation in a conventional microwave oven at 70°C and medium high power for 30s, resulting in simultaneous extraction and saponification. Ergosterol was detected by thin layer chromatography (TLC) and quantified using high performance liquid chromatography with diode array detection. The TLC method was novel and provided a simple, inexpensive method with utility in the field. The new method was particularly effective at extracting high yields of ergosterol from infected oil palm and enables rapid analysis of field samples on site, allowing infected oil palms to be treated or culled very rapidly. Some limitations of the method are discussed herein. The procedures lend themselves to controlling the disease more effectively and allowing more effective use of land currently employed to grow oil palms, thereby reducing pressure to develop new plantations.
    Matched MeSH terms: Plant Diseases/microbiology*
  7. Diversity of the cassiicolin gene in Corynespora cassiicola and relation with the pathogenicity in Hevea brasiliensis
    Déon M, Fumanal B, Gimenez S, Bieysse D, Oliveira RR, Shuib SS, et al.
    Fungal Biol, 2014 Jan;118(1):32-47.
    PMID: 24433675 DOI: 10.1016/j.funbio.2013.10.011
    Corynespora cassiicola is an important plant pathogenic Ascomycete causing the damaging Corynespora Leaf Fall (CLF) disease in rubber tree (Hevea brasiliensis). A small secreted glycoprotein named cassiicolin was previously described as an important effector of C. cassiicola. In this study, the diversity of the cassiicolin-encoding gene was analysed in C. cassiicola isolates sampled from various hosts and geographical origins. A cassiicolin gene was detected in 47 % of the isolates, encoding up to six distinct protein isoforms. In three isolates, two gene variants encoding cassiicolin isoforms Cas2 and Cas6 were found in the same isolate. A phylogenetic tree based on four combined loci and elucidating the diversity of the whole collection was strongly structured by the toxin class, as defined by the cassiicolin isoform. The isolates carrying the Cas1 gene (toxin class Cas1), all grouped in the same highly supported clade, were found the most aggressive on two rubber tree cultivars. Some isolates in which no Cas gene was detected could nevertheless generate moderate symptoms, suggesting the existence of other yet uncharacterized effectors. This study provides a useful base for future studies of C. cassiicola population biology and epidemiological surveys in various host plants.
    Matched MeSH terms: Plant Diseases/microbiology*
  8. Fulltext Identification of quantitative trait loci for blast resistance in BC₂F₃ and BC₂F5 advanced backcross families of rice
    Rahim HA, Bhuiyan MA, Lim LS, Sabu KK, Saad A, Azhar M, et al.
    Genet. Mol. Res., 2012;11(3):3277-89.
    PMID: 23079822 DOI: 10.4238/2012.September.12.11
    Advanced backcross families derived from Oryza sativa cv MR219/O. rufipogon IRGC105491 were utilized for identification of quantitative trait loci (QTL) for blast resistance using simple sequence repeat markers. Two hundred and sixty-one BC(2)F(3) families were used to construct a linkage map, using 87 markers, which covered 2375.2 cM of 12 rice chromosomes, with a mean density of 27.3 cM. The families were evaluated in a greenhouse for resistance to blast disease caused by pathotypes P7.2 and P5.0 of Magnaporthe oryzae. Five QTLs (qBL5.1, qBL5.2, qBL6.1, qBL8.1, and qBL10.1) for pathotype P5.0 and four QTLs (qBL5.3, qBL5.4, qBL7.1, and qBL8.2) for pathotype P7.2 were identified using the BC(2)F(3) families. Another linkage map was also constructed based on 31 BC(2)F(5) families, using 63 SSR markers, which covered 474.9 cM of 9 rice chromosomes, with a mean density of 8.01 cM. Five suggestive QTLs (qBL11.2, qBL11.3, qBL12.1, qBL12.2, qBL12.3) and one putative QTL (qBL2.1) were identified for pathotype P7.2. Also, seven suggestive QTLs (qBL1.1, qBL2.2, qBL4.1, qBL4.2, qBL5.3, qBL8.3, and qBL11.1) were detected for pathotype P5.0. We conclude that there is a non-race-specific resistance spectrum of O. rufipogon against M. oryzae pathotypes.
    Matched MeSH terms: Plant Diseases/microbiology
  9. Microsatellite and minisatellite markers based DNA fingerprinting and genetic diversity of blast and ufra resistant genotypes
    Latif MA, Rafii Yusop M, Motiur Rahman M, Bashar Talukdar MR
    C. R. Biol., 2011 Apr;334(4):282-9.
    PMID: 21513897 DOI: 10.1016/j.crvi.2011.02.003
    A total of 78 alleles and 29 loci were detected from nine microsatellite and three minisatellite markers, respectively across 26 blast and ufra disease resistant genotypes. For blast resistant genotypes, the Polymorphic Information Content (PIC) values ranged from 0.280 to 0.726 and RM21 was considered as the best marker. PIC values ranged from 0.5953 to 0.8296 for ufra resistant genotypes and RM23 was the best marker for characterization of ufra resistant genotypes. The genetic similarity analysis using UPGMA clustering generated nine clusters with coefficient of 0.66 for blast resistant genotypes while five genetic clusters with similarity coefficient of 0.42 for ufra resistant genotypes. In order to develop resistant varieties of two major diseases of rice, hybridisation should be made using the parents, BR29 and NJ70507, BR36 and NJ70507 for blast, while BR11 and Aokazi, BR3 and Aokazi, Rayda and BR3 and Rayda and BR11 for ufra.
    Matched MeSH terms: Plant Diseases/microbiology
  10. Effects of fusaric acid treatment on the protocorm-like bodies of Dendrobium sonia-28
    Dehgahi R, Zakaria L, Mohamad A, Joniyas A, Subramaniam S
    Protoplasma, 2016 Sep;253(5):1373-83.
    PMID: 26471909 DOI: 10.1007/s00709-015-0895-1
    Dendrobium sonia-28 is a popular orchid hybrid due to its flowering recurrence and dense inflorescences. Unfortunately, it is being decimated by fungal diseases, especially those caused by Fusarium proliferatum. In this study, selection of F. proliferatum-tolerant protocorm-like bodies (PLBs) was carried out by assessing the effects of differing concentrations of fusaric acid (FA). PLBs were cultured on Murashige and Skoog (MS) medium supplemented with 0.05 to 0.2 millimolar (mM) concentrations of FA. Higher concentrations of FA increased mortality of PLBs and reduced their growth. The survival rate for 0.05 mM FA was 20 % but only 1 % at the highest dose of 0.2 mM. Additionally, two different size ranges of PLBs were investigated, and growth increased more at lower FA concentrations for larger PLBs, whilst the growth rate of smaller PLBs was inhibited at an FA concentration of 0.2 mM. Histological examination using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) analyses disclosed severe cell wall and organelle damage, as well as stomatal closure in PLBs treated with the high FA concentrations. Reductions in plantlet growth were much greater at the highest concentrations of FA. Some randomly amplified polymorphic DNA (RAPD) markers clearly discriminated between selected and non-selected variants of Dendrobium sonia-28, showing different banding patterns for each FA concentration and specific bands for selected and control plants.
    Matched MeSH terms: Plant Diseases/microbiology
  11. Fulltext Preparation of Chitosan-Hexaconazole Nanoparticles as Fungicide Nanodelivery System for Combating Ganoderma Disease in Oil Palm
    Maluin FN, Hussein MZ, Yusof NA, Fakurazi S, Idris AS, Zainol Hilmi NH, et al.
    Molecules, 2019 Jul 08;24(13).
    PMID: 31288497 DOI: 10.3390/molecules24132498
    Fungicide is used to control fungal disease by destroying and inhibiting the fungus or fungal spores that cause the disease. However, failure to deliver fungicide to the disease region leads to ineffectiveness in the disease control. Hence, in the present study, nanotechnology has enabled the fungicide active agents (hexaconazole) to be encapsulated into chitosan nanoparticles with the aim of developing a fungicide nanodelivery system that can transport them more effectively to the target cells (Ganoderma fungus). A pathogenic fungus, Ganoderma boninense (G. boninense), is destructive to oil palm whereby it can cause significant loss to oil palm plantations located in the Southeast Asian countries, especially Malaysia and Indonesia. In regard to this matter, a series of chitosan nanoparticles loaded with the fungicide, hexaconazole, was prepared using various concentrations of crosslinking agent sodium tripolyphosphate (TPP). The resulting particle size revealed that the increase of the TPP concentration produced smaller particles. In addition, the in vitro fungicide released at pH 5.5 demonstrated that the fungicide from the nanoparticles was released in a sustainable manner with a prolonged release time up to 86 h. On another note, the in vitro antifungal studies established that smaller particle size leads to lower half maximum effective concentration (EC50) value, which indicates higher antifungal activity against G. boninense.
    Matched MeSH terms: Plant Diseases/microbiology*
  12. Sheath blight of rice: a review and identification of priorities for future research
    Singh P, Mazumdar P, Harikrishna JA, Babu S
    Planta, 2019 Nov;250(5):1387-1407.
    PMID: 31346804 DOI: 10.1007/s00425-019-03246-8
    MAIN CONCLUSION: Rice sheath blight research should prioritise optimising biological control approaches, identification of resistance gene mechanisms and application in genetic improvement and smart farming for early disease detection. Rice sheath blight, caused by Rhizoctonia solani AG1-1A, is one of the most devasting diseases of the crop. To move forward with effective crop protection against sheath blight, it is important to review the published information related to pathogenicity and disease management and to determine areas of research that require deeper study. While progress has been made in the identification of pathogenesis-related genes both in rice and in the pathogen, the mechanisms remain unclear. Research related to disease management practices has addressed the use of agronomic practices, chemical control, biological control and genetic improvement: Optimising nitrogen fertiliser use in conjunction with plant spacing can reduce spread of infection while smart agriculture technologies such as crop monitoring with Unmanned Aerial Systems assist in early detection and management of sheath blight disease. Replacing older fungicides with natural fungicides and use of biological agents can provide effective sheath blight control, also minimising environmental impact. Genetic approaches that show promise for the control of sheath blight include treatment with exogenous dsRNA to silence pathogen gene expression, genome editing to develop rice lines with lower susceptibility to sheath blight and development of transgenic rice lines overexpressing or silencing pathogenesis related genes. The main challenges that were identified for effective crop protection against sheath blight are the adaptive flexibility of the pathogen, lack of resistant rice varieties, abscence of single resistance genes for use in breeding and low access of farmers to awareness programmes for optimal management practices.
    Matched MeSH terms: Plant Diseases/microbiology
  13. Fulltext RNA-seq data of Ganoderma boninense at axenic culture condition and under in planta pathogen-oil palm (Elaeis guineensis Jacq.) interaction
    Wong MY, Govender NT, Ong CS
    BMC Res Notes, 2019 Sep 24;12(1):631.
    PMID: 31551084 DOI: 10.1186/s13104-019-4652-y
    OBJECTIVE: Basal stem rot disease causes severe economic losses to oil palm production in South-east Asia and little is known on the pathogenicity of the pathogen, the basidiomyceteous Ganoderma boninense. Our data presented here aims to identify both the house-keeping and pathogenicity genes of G. boninense using Illumina sequencing reads.

    DESCRIPTION: The hemibiotroph G. boninense establishes via root contact during early stage of colonization and subsequently kills the host tissue as the disease progresses. Information on the pathogenicity factors/genes that causes BSR remain poorly understood. In addition, the molecular expressions corresponding to G. boninense growth and pathogenicity are not reported. Here, six transcriptome datasets of G. boninense from two contrasting conditions (three biological replicates per condition) are presented. The first datasets, collected from a 7-day-old axenic condition provide an insight onto genes responsible for sustenance, growth and development of G. boninense while datasets of the infecting G. boninense collected from oil palm-G. boninense pathosystem (in planta condition) at 1 month post-inoculation offer a comprehensive avenue to understand G. boninense pathogenesis and infection especially in regard to molecular mechanisms and pathways. Raw sequences deposited in Sequence Read Archive (SRA) are available at NCBI SRA portal with PRJNA514399, bioproject ID.

    Matched MeSH terms: Plant Diseases/microbiology
  14. Antagonistic effects of Streptomyces violaceusniger strain G10 on Fusarium oxysporum f.sp. cubense race 4: indirect evidence for the role of antibiosis in the antagonistic process
    Getha K, Vikineswary S
    J Ind Microbiol Biotechnol, 2002 Jun;28(6):303-10.
    PMID: 12032802
    Fusarium oxysporum f.sp. cubense is the causal pathogen of wilt disease of banana. A cost-effective measure of control for this disease is still not available. Streptomyces violaceusniger strain G10 acts as an antifungal agent antagonistic towards many different phytopathogenic fungi, including different pathogenic races of the Fusarium wilt pathogen. In an attempt to understand the mode of action of this antagonist in nature, the interaction between S. violaceusniger strain G10 and F. oxysporum f.sp. cubense was first studied by paired incubation on agar plates. Evidence for the in vitro antibiosis of strain G10 was demonstrated by inhibition zones in the "cross-plug" assay plates. Microscopic observations showed lysis of hyphal ends in the inhibited fungal colonies. Culture of strain G10 in liquid media produces antifungal metabolites, which showed in vitro antagonistic effects against F. oxysporum f.sp. cubense such as swelling, distortion and excessive branching of hyphae, and inhibition of spore germination. An indirect method was used to show that antibiosis is one of the mechanisms of antagonism by which strain G10 acts against F. oxysporun f.sp. cubense in soil. This study suggests the potential of developing strain G10 for the biological control of Fusarium wilt disease of banana.
    Matched MeSH terms: Plant Diseases/microbiology*
  15. Fulltext Haplotype divergence and multiple candidate genes at Rphq2, a partial resistance QTL of barley to Puccinia hordei
    Yeo FK, Wang Y, Vozabova T, Huneau C, Leroy P, Chalhoub B, et al.
    Theor Appl Genet, 2016 Feb;129(2):289-304.
    PMID: 26542283 DOI: 10.1007/s00122-015-2627-5
    Rphq2, a minor gene for partial resistance to Puccinia hordei , was physically mapped in a 188 kbp introgression with suppressed recombination between haplotypes of rphq2 and Rphq2 barley cultivars.
    Matched MeSH terms: Plant Diseases/microbiology
  16. Fulltext Application of Ground-Based LiDAR for Analysing Oil Palm Canopy Properties on the Occurrence of Basal Stem Rot (BSR) Disease
    Husin NA, Khairunniza-Bejo S, Abdullah AF, Kassim MSM, Ahmad D, Azmi ANN
    Sci Rep, 2020 04 15;10(1):6464.
    PMID: 32296108 DOI: 10.1038/s41598-020-62275-6
    Ground-based LiDAR also known as Terrestrial Laser Scanning (TLS) technology is an active remote sensing imaging method said to be one of the latest advances and innovations for plant phenotyping. Basal Stem Rot (BSR) is the most destructive disease of oil palm in Malaysia that is caused by white-rot fungus Ganoderma boninense, the symptoms of which include flattening and hanging-down of the canopy, shorter leaves, wilting green fronds and smaller crown size. Therefore, until now there is no critical investigation on the characterisation of canopy architecture related to this disease using TLS method was carried out. This study proposed a novel technique of BSR classification at the oil palm canopy analysis using the point clouds data taken from the TLS. A total of 40 samples of oil palm trees at the age of nine-years-old were selected and 10 trees for each health level were randomly taken from the same plot. The trees were categorised into four health levels - T0, T1, T2 and T3, which represents the healthy, mildly infected, moderately infected and severely infected, respectively. The TLS scanner was mounted at a height of 1 m and each palm was scanned at four scan positions around the tree to get a full 3D image. Five parameters were analysed: S200 (canopy strata at 200 cm from the top), S850 (canopy strata at 850 cm from the top), crown pixel (number of pixels inside the crown), frond angle (degree of angle between fronds) and frond number. The results taken from statistical analysis revealed that frond number was the best single parameter to detect BSR disease as early as T1. In classification models, a linear model with a combination of parameters, ABD - A (frond number), B (frond angle) and D (S200), delivered the highest average accuracy for classification of healthy-unhealthy trees with an accuracy of 86.67 per cent. It also can classify the four severity levels of infection with an accuracy of 80 per cent. This model performed better when compared to the severity classification using frond number. The novelty of this research is therefore on the development of new approach to detect and classify BSR using point clouds data of TLS.
    Matched MeSH terms: Plant Diseases/microbiology*
  17. Transcriptomic analysis of pepper plants provides insights into host responses to Fusarium solani infestation
    Lau ET, Khew CY, Hwang SS
    J Biotechnol, 2020 May 20;314-315:53-62.
    PMID: 32302654 DOI: 10.1016/j.jbiotec.2020.03.014
    Black pepper is an important commodity crop in Malaysia that generates millions of annual revenue for the country. However, black pepper yield is affected by slow decline disease caused by a soil-borne fungus Fusarium solani. RNA sequencing transcriptomics approach has been employed in this study to explore the differential gene expression in susceptible Piper nigrum L. and resistant Piper colubrinum Link. Gene expression comparative analysis of the two pepper species has yielded 2,361 differentially expressed genes (DEGs). Among them, higher expression of 1,426 DEGs was detected in resistant plant. These DEGs practically demonstrated the major branches of plant-pathogen interaction pathway (Path: ko04626). We selected five groups of defence-related DEGs for downstream qRT-PCR analysis. Cf-9, the gene responsible for recognizing fungal avirulence protein activity was found inexpressible in susceptible plant. However, this gene exhibited promising expression in resistant plant. Inactivation of Cf-9 could be the factor that causes susceptible plant fail in recognition of F. solani and subsequently delay activation of adaptive response to fungal invasion. This vital study advance the understanding of pepper plant defence in response to F. solani and aid in identifying potential solution to manage slow decline disease in black pepper cultivation.
    Matched MeSH terms: Plant Diseases/microbiology
  18. Fluorescence-based immunoassay for the detection of Xanthomonas oryzae pv. oryzae in rice leaf
    Awaludin N, Abdullah J, Salam F, Ramachandran K, Yusof NA, Wasoh H
    Anal Biochem, 2020 12 01;610:113876.
    PMID: 32750357 DOI: 10.1016/j.ab.2020.113876
    The identification of rice bacterial leaf blight disease requires a simple, rapid, highly sensitive, and quantitative approach that can be applied as an early detection monitoring tool in rice health. This paper highlights the development of a turn-off fluorescence-based immunoassay for the early detection of Xanthomonas oryzae pv. oryzae (Xoo), a gram-negative bacterium that causes rice bacterial leaf blight disease. Antibodies against Xoo bacterial cells were produced as specific bio-recognition molecules and the conjugation of these antibodies with graphene quantum dots and gold nanoparticles was performed and characterized, respectively. The combination of both these bio-probes as a fluorescent donor and metal quencher led to changes in the fluorescence signal. The immunoreaction between AntiXoo-GQDs, Xoo cells, and AntiXoo-AuNPs in the immuno-aggregation complex led to the energy transfer in the turn-off fluorescence-based quenching system. The change in fluorescence intensity was proportional to the logarithm of Xoo cells in the range of 100-105 CFU mL-1. The limit of detection was achieved at 22 CFU mL-1 and the specificity test against other plant disease pathogens showed high specificity towards Xoo. The detection of Xoo in real plant samples was also performed in this study and demonstrated satisfactory results.
    Matched MeSH terms: Plant Diseases/microbiology
  19. Detection of Oil Palm Root Penetration by Agrobacterium-Mediated Transformed Ganoderma boninense, Expressing Green Fluorescent Protein
    Govender N, Wong MY
    Phytopathology, 2017 04;107(4):483-490.
    PMID: 27918241 DOI: 10.1094/PHYTO-02-16-0062-R
    A highly efficient and reproducible Agrobacterium-mediated transformation protocol for Ganoderma boninense was developed to facilitate observation of the early stage infection of basal stem rot (BSR). The method was proven amenable to different explants (basidiospore, protoplast, and mycelium) of G. boninense. The transformation efficiency was highest (62%) under a treatment combination of protoplast explant and Agrobacterium strain LBA4404, with successful expression of an hyg marker gene and gus-gfp fusion gene under the control of heterologous p416 glyceraldehyde 3-phosphate dehydrogenase promoter. Optimal transformation conditions included a 1:100 Agrobacterium/explant ratio, induction of Agrobacterium virulence genes in the presence of 250 μm acetosyringone, co-cultivation at 22°C for 2 days on nitrocellulose membrane overlaid on an induction medium, and regeneration of transformants on potato glucose agar prepared with 0.6 M sucrose and 20 mM phosphate buffer. Evaluated transformants were able to infect root tissues of oil palm plantlets with needle-like microhyphae during the penetration event. The availability of this model pathogen system for BSR may lead to a better understanding of the pathogenicity factors associated with G. boninense penetration into oil palm roots.
    Matched MeSH terms: Plant Diseases/microbiology*
  20. Oil Palm Defensin: A Thermal Stable Peptide that Restricts the Mycelial Growth of Ganoderma boninense
    Tan YC, Ang CL, Wong MY, Ho CL
    Protein Pept Lett, 2016;23(11):994-1002.
    PMID: 27719656
    Plant defensins are plant defence peptides that have many different biological activities, including antifungal, antimicrobial, and insecticidal activities. A cDNA (EgDFS) encoding defensin was isolated from Elaeis guineensis. The open reading frame of EgDFS contained 231 nucleotides encoding a 71-amino acid protein with a predicted molecular weight at 8.69 kDa, and a potential signal peptide. The eight highly conserved cysteine sites in plant defensins were also conserved in EgDFS. The EgDFS sequence lacking 30 amino acid residues at its N-terminus (EgDFSm) was cloned into Escherichia coli BL21 (DE3) pLysS and successfully expressed as a soluble recombinant protein. The recombinant EgDFSm was found to be a thermal stable peptide which demonstrated inhibitory activity against the growth of G. boninense possibly by inhibiting starch assimilation. The role of EgDFSm in oil palm defence system against the infection of pathogen G. boninense was discussed.
    Matched MeSH terms: Plant Diseases/microbiology
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