Latiffah Zakaria

Molecular Identification of Fusarium Species in Gibberella fujikuroi Species Complex from Rice, Sugarcane and Maize from Peninsular Malaysia

The objective of this study was to identify Fusarium species in the Gibberella fujikuroi species complex from rice, sugarcane and maize as most of the Fusarium species in the species complex are found on the three crops. Isolates used were collected from the field and obtained from culture collection. The Fusarium isolates were initially sorted based on morphology and identifications confirmed based on the DNA sequence of the translation elongation factor 1-α (TEF-1α) gene. Based on the closest match of BLAST analysis, five species were recovered, namely, F. sacchari, F. fujikuroi, F. proliferatum, F. andiyazi and F. verticillioides. This is the first report regarding F. andiyazi from rice in Malaysia and Southeast Asia. The phylogenetic tree generated by using the neighbor joining method showed that isolates from the same species were grouped in the same clade. The present study indicated that Fusarium species in the G. fujikuroi species complex are widespread in rice, sugarcane and maize in Peninsular Malaysia. The findings also suggest that the use of morphological characters for identification of Fusarium species in the G. fujikuroi species complex from the three crops will lead to incorrect species designation.

Morphological and Phylogenetic Analysis of Fusarium solani Species Complex in Malaysia

Members of Fusarium solani species complex (FSSC) have been known as plant, animal, and human pathogens. Nevertheless, the taxonomic status of such an important group of fungi is still very confusing and many new species as well as lineages have been elucidated recently. Unfortunately, most of the new taxa came from temperate and subtropical regions. Therefore, the objectives of the present study were to identify strains of FSSC recovered from different sources in Malaysia. In the present study, 55 strains belonging to the FSSC were examined and phylogenetically analyzed on the basis of internal transcribed spacer (ITS) regions and partial translation elongation factor-1 (TEF-1α) sequences. Based on morphological features, a total of 55 strains were selected for molecular studies. Based on morphological features, the strains were classified into four described Fusarium species, namely Fusarium keratoplasticum, Fusarium falciforme, FSSC 5, and Fusarium cf. ensiforme, and one unknown phylogenetic species was introduced. Although the data obtained from morphological and molecular studies sufficiently supported each other, the phylogenetic trees based on ITS and TEF-1α dataset clearly distinguished closely related species and distinctly separated all morphological taxa. All members of FSSC in this research were reported for the first time for Malaysian mycoflora.

Enhancement of anti-candidal activity of endophytic fungus Phomopsis sp. ED2, isolated from Orthosiphon stamineus Benth, by incorporation of host plant extract in culture medium

This study examined the effect of host extract in the culture medium on anti-candidal activity of Phomopsis sp. ED2, previously isolated from the medicinal herb Orthosiphonstamineus Benth. Interestingly, upon addition of aqueous host extract to the culture medium, the ethyl acetate extract prepared from fermentative broth exhibited moderate anti-candidal activity in a disc diffusion assay. The minimal inhibitory concentration of this extract was 62.5 μg/ml and it only exhibited fungistatic activity against C. albicans. In the time-kill study, a 50% growth reduction of C. albicans was observed at 31.4 h for extract from the culture incorporating host extract. In the bioautography assay, only one single spot (Rf 0.59) developed from the extract exhibited anti-candidal activity. A spot with the a similar Rf was not detected for the crude extract from YES broth without host extract. This indicated that the terpenoid anti-candidal compound was only produced when the host extract was introduced into the medium. The study concluded that the incorporation of aqueous extract of the host plant into the culture medium significantly enhanced the anti-candidal activity of Phomopsis sp. ED2.

Occurrence of Fusarium spp. associated with root tissues and rhizosphere soils of forest trees and assessment of their pathogenicity on Prunus amygdalus seedlings

Occurrence, distribution and pathogenicity of Fusarium spp. associated with roots and rhizosphere soils of forest trees were studied. Fusarium spp. was isolated from phloem and sapwood of forest trees and composite rhizosphere soil samples collected from highly diversified geographical and climatic regions of the west of Iran and identified based on their morphological characteristics. Only three Fusarium spp. (F. oxysporum, F. solani and F. eumartii) was isolated from roots. F. nygamai, F. graminearum, F. scirpi, F. proliferatum, F. anthophilum, F. longipes and F. chlamydosporum were recovered from soil samples collected from warm and moderately warm regions, while F. culmorum, F. sporotrichioides, F. sambucinum and F. subglutinans were recovered from cold regions. F. solani, F. oxysporum, F. semitectum, F. equiseti, F. verticillioides, F. merismoides and F. avenaceum were present in all climatic regions. In the bark inoculation tests, selected Fusarium strains representing all species were evaluated for their pathogenicity on stems of healthy Prunus amygdalus under greenhouse conditions. Stem rot assessment revealed that F. oxysporum, F. solani and F. eumartii were the most damaging species.

The First Report of Penicillium georgiense in Malaysia.

Abstract Penicillium georgiense was isolated from sandy beach soil from Batu Ferringhi beach, Penang Island, Malaysia. The identification was based on morphological characteristics and phylogenetic analysis of internal transcribed spacer regions and β-tubulin sequences. To the best of our knowledge, this is the first report of P. georgiense in Malaysia.

First Report of Stemphylium lycopersici Causing Leaf Spot on Sansevieria trifasciata in Malaysia

Sansevieria trifasciata is widely planted in Malaysia as an indoor or outdoor ornamental plant. In June 2016, several S. trifasciata plants exhibiting symptoms of leaf spots were observed and collected from outdoor planting in Tanah Rata, Cameron Highlands, Pahang, Malaysia. Disease severity and incidence were estimated at 25% and 30% (total of 30 plants), respectively. The lesions began as circular brown spots which gradually enlarged, forming oval to irregular chlorotic lesions with reddish- brown borders on the leaves. As the disease progressed, the center of the lesions became sunken and dry. Symptomatic leaf segments (~1 cm2) were surface sterilized in 10% bleach (1% sodium hypochlorite) for 3 minutes, placed on potato dextrose agar (PDA) and incubated at 28°C for 3 to 5 days with a 12-h photoperiod. Fungal mycelia growing from the edges of the leaf segments were transferred onto PDA prior to obtaining pure cultures using a single spore isolation technique. Two isolates were recovered from the sympto...

Characterisation of Neoscytalidium dimidiatum causing leaf blight on Sansevieria trifasciata in Malaysia

Sansevieria trifasciata showing symptoms of leaf blight were observed in several states of Malaysia. Based on morphology and DNA sequences of the Internal Transcribed Spacer (ITS) region, nine isolates of Neoscytalidium dimidiatum were identified. Phylogenetic analysis grouped the isolates of N. dimidiatum from S. trifasciata with the epitype of Neoscytalidium dimidiatum (CBS499.66) from mango. Pathogenicity test showed that all isolates of N. dimidiatum caused leaf blight on S. trifasciata and fulfilled Koch’s postulates.

Molecular characterization and pathogenicity of Colletotrichum sp. from guava

Guava (Psidium guajava) fruit is vulnerable to postharvest diseases, such as anthracnose. In the present study, molecular characterisation and pathogenicity of Colletotrichum associated with antharcnose disease of guava fruit were conducted. From anthracnose lesion of guava, 20 isolates were successfully recovered. Based on colony colours, conidia, appressoria and presence or absence of setae, and ITS regions and ß-tubulin gene sequences, the isolates were identified as Colletotrichum gloeosporioides. Phylogenetic analysis based on combined data-sets using neighbour-joining method showed that C. gloeosporioides isolates did not group with C. gloeosporioides epitype strain, and thus the isolates were referred to as C. gloeosporioides species complex or C. gloeosporioides sensu lato. Pathogenicity tests using wounded treatment showed that C. gloeosporioides isolates from guava were pathogenic causing anthracnose on the fruits. The present study showed that C. gloeosporioides sensu lato is the most common species causing antharcnose disease of guava fruit.

Molecular Identification of Endophytic Fungi from Banana Leaves (Musa spp.)

Endophytic fungi are part of microbial community found in various types of plant tissues including the leave, and display a range of symbiotic interactions with the plant host. In this study, endophytic fungi isolated from banana leaves were identified using ITS (Internal Transcribed Spacer region) sequences of which 10 genera comprising 17 species were molecularly identified. Endophytic fungal species identified were Nigrospora oryzae, Nigrospora sphaerica, Colletotrichum gloeosporioides, Colletotrichum siamense, Fusarium equiseti, Fusarium chlamydosporum, Phoma sorghina, Pestalotiopsis oxyanthi, Pestalotiopsis theae, Pestalotiopsis eugeniae, Penicillium steckii, Penicillium purpurogenum, Bipolaris papendorfii, Bipolaris sp., Lasidiodiplodia theobromae, Cochliobolus intermedius dan Aspergillus niger. The present study showed that several endophytic fungal genera/species are common plant pathogen and there is a possibility that these endophytes can become pathogenic. Some of the fungal endophyte might be mutualist or saprophyte.

Characterization and pathogenicity of Fusarium species associated with leaf spot of mango (Mangifera indica L.)

Leaf spot diseases are mainly caused by fungi including Fusarium. In the present study several species of Fusarium were isolated from the leaf spot lesion of mango (Mangifera indica L.) Based on morphological characteristics, TEF-1α sequences and phylogenetic analysis, five species were identified as F. proliferatum, F. semitectum, F. mangiferae, F. solani and F. chlamydosporum. Pathogenicity test indicated that representative isolates of F. proliferatum, F. semitectum and F. chlamydosporum were pathogenic on mango leaves causing leaf spot with low to moderate virulence. Nevertheless, abundance of spots on the leaf can disrupt photosynthesis which in turn reduced growth, and lead to susceptibility to infection by opportunistic pathogens due to weakening of the plant. Fusarium solani and F. mangiferae were non-pathogenic and it is possible that both species are saprophyte which associated with nutrient availability on the surface of the leaf through decaying leave tissues. The occurrence of Fusarium spp. on the leaf spot lesion and the effect from the disease needs to be considered when developing disease management method of mango cultivation as numerous spot on the leaves could effect the photosynthesis process and finally giving low yield and less quality of mango.