1.Identification and Characterization of Macrophomina phaseolina Causing Leaf Blight on White Spider Lilies (Crinum asiaticum and Hymenocallis littoralis) in Malaysia
Abd Rahim HUDA-SHAKIRAH ; Yee Jia KEE ; Abu Bakar Mohd HAFIFI ; Nurul Nadiah MOHAMAD AZNI ; Latiffah ZAKARIA ; Masratul Hawa MOHD
Mycobiology 2019;47(4):408-414
Crinum asiaticum and Hymenocallis littoralis, commonly known as spider lilies are bulbous perennial and herbaceous plants that widely planted in Malaysia as ornamental. During 2015–2016, symptom of leaf blight was noticed on the hosts from several locations in Penang. The symptom appeared as irregular brown to reddish lesions surrounded by yellow halos. As the disease progressed, the infected leaves became blighted, dried, and fell off with the presence of black microsclerotia and pycnidia on the lesions parts. The present study was conducted to investigate the causal pathogen of leaf blight on C. asiaticum and H. littoralis. Based on morphological characteristics and DNA sequences of internal transcribed spacer (ITS) region and translation elongation factor 1-alpha (TEF1-α) gene, the causal pathogen was identified as Macrophomina phaseolina. Phylogenetic analysis of combined dataset of ITS and TEF1-α grouped the isolates studied with other isolates of M. phaseolina from GenBank. The grouping of the isolates was supported by 96% bootstrap value. Pathogenicity test proved the role of the fungus in causing leaf blight on both hosts.
2.Extracellular enzymatic activity of endophytic fungi isolated from spines of rattan palm (Calamus castaneus Griff.)
Nurul Farizah Azuddin ; Masratul Hawa Mohd ; Nik Fadzly Nik Rosely ; Asyraf Mansor ; Latiffah Zakaria
Malaysian Journal of Microbiology 2024;20(no.1):7-14
Aims:
Calamus castaneus is a non-climbing rattan plant widely distributed in tropical rainforests. The sharp spines of rattan palm harbour endophytic fungi, which may produce extracellular enzymes that contribute to various functions without harming the host plant. This study was aimed to evaluate the ability of fungal endophytes isolated from the C. castaneus spines to produce extracellular enzymes, including protease, pectinase, amylase, lipase and cellulase.
Methodology and results:
Thirty-four (34) endophytic fungal isolates were tested for their ability to produce extracellular enzymes using the agar plate method. Enzyme activity was measured using the enzyme index (EI) by measuring the halo (clear zone) on the agar medium. The EI value indicates the strength of the enzyme produced by the endophytes. Results demonstrated that all thirty-four fungal endophytes could produce at least one extracellular enzyme. Xylaria cubensis BR90 showed the highest protease activity of 5.73 EI. Muyocopron laterale (SM60) showed the highest pectinase activity of 2.74 EI. For lipase and cellulase activities, Cyphellophora guyanensis (BR71) produced 2.26 EI while Acremonium hennebertii (BR70) produced 1.97 EI, respectively.
Conclusion, significance and impact of study
Endophytic fungi from spines of C. castaneus were able to produce cellulase, pectinase, lipase, protease and amylase. The extracellular enzymes degraded different substrates, suggesting different types of interaction of the fungal endophytes with the host plant.
3.Occurrence and identification of Penicillium and Talaromyces species from beach sand
Teh Li Yee ; Nurul Farizah Azuddin ; Masratul Hawa Mohd ; Latiffah Zakaria
Malaysian Journal of Microbiology 2022;18(6):652-664
Aims:
Penicillium and Talaromyces were among the species of microfungi that inhabit beach sand in Batu Ferringhi Beach, Penang Island, Malaysia. Previously, Talaromyces was described as the sexual stage of Penicillium, but both are now accepted as separate genera based on molecular phylogeny. The aim of the present study was to identify species of Penicillium and Talaromyces that are present in beach sand in Malaysia.
Methodology and results:
Species identities were confirmed according to similarities of the internal transcribed spacer regions and β-tubulin gene sequences and a phylogenetic analysis based on both regions/gene. Nine Penicillium spp. were identified as P. georgiense, P. chermesinum, P. pimiteouiense, P. citrinum, P. oxalicum, P. daleae, P. rolfsii and Penicillium sp. and the four Talaromyces spp. were T. siamense, T. atroroseus, T. minioluteus and T. fusiformis.
Conclusion, significance and impact of study
These findings showed that beach sand harboured a variety of Penicillium and Talaromyces species. The occurrence of Penicillium and Talaromyces in beach sands is associated with the organic matter in the sand, which provides suitable substrates and nutrient sources. Due to this, beach sand might harbour many potentially pathogenic or opportunistic species that may pose a health concern to immunocompromised individuals.
Penicillium
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Talaromyces
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Sand
4.Morphological and molecular identification of Pyricularia oryzae causing blast disease on rice (Oryza sativa)
Izah Adlina Mohamad Shukri ; Ahmad Ramli Mohd Yahya ; Masratul Hawa Mohd ; Nur Asshifa Md Noh
Malaysian Journal of Microbiology 2023;19(no.6):586-593
Aims:
Rice (Oryza sativa) is one of Malaysia’s most significant crops. Rice blast caused by Pyricularia oryzae is one of the most serious diseases of Oryza sativa, causing significant damage to the Malaysian rice crop and impacting productivity. This study was carried out to isolate and characterize phytopathogenic fungal isolates associated with rice blast collected in a paddy field in Alor Setar, Kedah, Malaysia.
Methodology and results:
Morphological characterization of seven fungal isolates obtained showed thin, white, and grayish green mycelia and the reverse colony was light yellow to brown. The fungal isolates produced two-septate
pyriform (pear-shaped) conidia with solitary, unbranched and light brown conidiophores. Pathogenicity tests of all isolates on rice leaves revealed diamond-shaped symptoms with a grayish center and brown edge. All isolates showed similar morphological and pathogenicity characteristics; thus, a representative isolate was further identified through DNA sequencing and phylogenetic analysis of the internal transcribed spacer (ITS) region for species confirmation. Based on DNA sequences of ITS and phylogenetic analysis, the representative isolate was confirmed as P. oryzae.
Conclusion, significance and impact of study
Seven isolates morphologically identified as Pyricularia sp. were tested as pathogenic by causing rice blast disease. Representative isolate P2 (USM-PD1) was confirmed to be P. oryzae by DNA sequencing and phylogenetic analysis of the ITS region. This study provides information on the etiology and symptomatology of rice blast disease caused by P. oryzae USM-PD1 that can be applied to diagnose and mitigate the threat posed by this plant pathogen for the disease management.