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Toxigenicity of some fusaria associated with plant and human diseases in the Malaysian peninsula

Salleh B, Strange RN

J. Gen. Microbiol., 1988 Mar;134(3):841-7.
PMID: 3183622

In the course of a plant disease survey of the Malaysian Peninsula (Malaysia comprises the Malaysian Peninsula, Sabah and Sarawak) during the period 1981-1986, more than 1000 isolates of Fusarium were obtained from diseased plants and seeds. Two further isolates were obtained from patients admitted to hospitals in the same area. The occurrences of F. proliferatum, F. nygamai and F. longipes are new records for the Malaysian Peninsula and the association of F. solani and F. oxysporum var. redolens with human diseases does not seem to have been reported previously. Ten representative species which could be classified into seven sections of the genus were selected for studies of their toxigenicity in liquid cultures and/or on rice. Crude toxin preparations from culture filtrates or extracts of the inoculated rice were tested for toxicity to brine shrimp larvae and tobacco mesophyll protoplasts. The protoplasts were more sensitive than the brine shrimp larvae to the toxin preparations, except those from the isolates of F. solani and F. oxysporum var. redolens obtained from either humans or tobacco. The toxicity of the preparations from rice cultures per g rice was always greater than the toxicity per ml of culture filtrates from cultures grown on Czapek-Dox broth, Czapek-Dox supplemented with 1% (w/v) peptone or Czapek-Dox supplemented with 5% (w/v) tobacco extract. The activity of all toxin preparations was stable to heat. It is concluded that the occurrence of toxigenic species of Fusarium in the Malaysian Peninsula is widespread and that they may pose a serious threat to the health of human, animal and plant populations.

Matched MeSH terms: Fusarium/isolation & purification*
Occurrence, pathogenicity and distribution of Fusarium spp. in stored wheat seeds Kermanshah Province, Iran

Chehri K, Salleh B, Yli-Mattila T, Soleimani MJ, Yousefi AR

Pak J Biol Sci, 2010 Dec 15;13(24):1178-86.
PMID: 21313898

Fusarium is one of the most important pathogenic and toxigenic fungi widely distributed all over the world, including Iran. Fusarium species are found frequently in stored agriculture products especially wheat. The objective of this study was to identify Fusarium species associated with stored wheat seeds and their pathogenicity on root and head of wheat in Kermanshah, the leading province in wheat production in Iran. In this survey 75 seed samples of stored wheat were collected from 10 different regions during 2006-2008 and tested for the presence of Fusarium. Fusarium spp. were found in 51 (68%) of 75 samples. A total of 580 Fusarium strains were isolated, identified and preserved. All these strains belong to 20 Fusarium spp. according to morphological characters. Each conidial suspension of selected strains representing all species was evaluated for their pathogenicity on roots and spikes of healthy wheat var. Fallat in the greenhouse. F. graminearum, F. crookwellense, F. trichothecioides, F. culmorum and F. verticillioides were the most pathogenic to wheat's head. Foot rot assessment revealed that F. pseudograminearum and F. culmorum were the most damaging species. Of the Fusarium isolates, F. graminearum was the most prevalent followed by F. verticillioides and F. proliferatum. This is the first comprehensive report on identity and distribution of Fusarium spp. from stored wheat seeds in Iran while F. nelsonii was reported for the first time from wheat seeds in Iran.

Matched MeSH terms: Fusarium/isolation & purification*
Fulltext Characterization of Fusarium species section Liseola by restriction analysis of the IGS region

Heng MH, Baharuddin S, Latiffah Z

Genet. Mol. Res., 2012;11(1):383-92.
PMID: 22370941 DOI: 10.4238/2012.February.16.4

Fusarium species section Liseola namely F. fujikuroi, F. proliferatum, F. andiyazi, F. verticillioides, and F. sacchari are well-known plant pathogens on rice, sugarcane and maize. In the present study, restriction analysis of the intergenic spacer regions (IGS) was used to characterize the five Fusarium species isolated from rice, sugarcane and maize collected from various locations in Peninsular Malaysia. From the analysis, and based on restriction patterns generated by the six restriction enzymes, Bsu151, BsuRI, EcoRI, Hin6I, HinfI, and MspI, 53 haplotypes were recorded among 74 isolates. HinfI showed the most variable restriction patterns (with 11 patterns), while EcoRI showed only three patterns. Although a high level of variation was observed, it was possible to characterize closely related species and isolates from different species. UPGMA cluster analysis showed that the isolates of Fusarium from the same species were grouped together regardless of the hosts. We conclude that restriction analysis of the IGS regions can be used to characterize Fusarium species section Liseola and to discriminate closely related species as well as to clarify their taxonomic position.

Matched MeSH terms: Fusarium/isolation & purification
Climatic conditions and farm practices affected the prevalence of Aspergillus section Flavi on different types of dairy goat's feed

Azman NI, Wan-Mustapha WN, Goh YM, Hassim HA, Selamat J, Samsudin NIP

Int J Food Microbiol, 2021 Jun 02;347:109205.
PMID: 33901942 DOI: 10.1016/j.ijfoodmicro.2021.109205

The present work aimed to determine the prevalence of aflatoxigenic Aspergillus section Flavi on different types of dairy goat's feed samples obtained from four dairy goat's farms around the central region of Peninsular Malaysia, and to examine the effects of climatic conditions (temperature, relative humidity) of the dairy goat's farms, and their feeding and storage practices on the fungal prevalence of different types of dairy goat's feed. A total of 60 goat's feed samples were obtained, and their proximate composition and water activity were determined, following which they were cultivated on DRBC and AFPA for total fungal load and Aspergillus section Flavi load determination, respectively. Fungal isolates were identified morphologically, and toxigenicity potentials of Aspergillus section Flavi isolates were determined using CCA. The temperature and relative humidity data of all farms were obtained from the Malaysian Meteorological Department. The total fungal loads (on DRBC) of the goat's feed samples were log 0.767 to 7.071 CFU/g which included the common feed contaminants such as Aspergillus, Fusarium, and Penicillium. The Aspergillus section Flavi loads (on AFPA) were log 0.667 to 3.206 CFU/g. Farm A yielded the highest number of Aspergillus section Flavi isolates as well as the highest number of aflatoxigenic isolates. It was found that climatic conditions and different practices between farms positively influenced the fungal prevalence on goat's feed samples based on the Pearson correlation analysis. The prevalence of mycotoxigenic isolates on goat's feed warrants for urgent intervention to ensure that goats are being fed with nutritionally adequate and safe feed. The presence of aflatoxigenic Aspergillus section Flavi isolates indicates the risk of aflatoxin B1 contamination on the goat's feed, aflatoxicosis development in the goats, and aflatoxin M1 bio-transformation in the goat's milk. This is a potential threat to the flourishing goat's milk industry in Malaysia.

Matched MeSH terms: Fusarium/isolation & purification*
Genetic diversity and pathogenicity of Fusarium species associated with fruit rot disease in banana across Peninsular Malaysia

Abd Murad NB, Mohamed Nor NMI, Shohaimi S, Mohd Zainudin NAI

J Appl Microbiol, 2017 Dec;123(6):1533-1546.
PMID: 28891270 DOI: 10.1111/jam.13582

AIMS: The aims of this study were to identify the Fusarium isolates based on translation elongation factor (tef) 1α sequence, to determine the genetic diversity among isolates and species using selected microsatellite markers and to examine the pathogenicity of Fusarium isolates causing fruit rot disease of banana.
METHODS AND RESULTS: One-hundred and thirteen microfungi isolates were obtained from fruit rot infected banana in Peninsular Malaysia. However, this study was focused on the dominant number of the discovered microfungi that belongs to the genus Fusarium; 48 isolates of the microfungi have been identified belonging to 11 species of Fusarium, namely Fusarium incarnatum, Fusarium equiseti, Fusarium camptoceras, Fusarium solani, Fusarium concolor, Fusarium oxysporum, Fusarium proliferatum, Fusarium verticillioides, Fusarium sacchari, Fusarium concentricum and Fusarium fujikuroi. All Fusarium isolates were grouped into their respective clades indicating their similarities and differences in genetic diversity among isolates. Out of 48 Fusarium isolates tested, 42 isolates caused the fruit rot symptom at different levels of severity based on Disease Severity Index (DSI). The most virulent isolate was F. proliferatum B2433B with DSI of 100%.
CONCLUSIONS: All the isolated Fusarium species were successfully identified and some of them were confirmed as the causal agents of pre- and postharvest fruit rot in banana across Peninsular Malaysia.
SIGNIFICANCE AND IMPACT OF THE STUDY: Our results will provide additional information regarding new report of Fusarium species in causing banana fruit rot and in the search of potential biocontrol agent of the disease.

Matched MeSH terms: Fusarium/isolation & purification
Characterization and pathogenicity of Fusarium species associated with leaf spot of mango (Mangifera indica L.)

Omar NH, Mohd M, Mohamed Nor NMI, Zakaria L

Microb Pathog, 2018 Jan;114:362-368.
PMID: 29233777 DOI: 10.1016/j.micpath.2017.12.026

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.

Matched MeSH terms: Fusarium/isolation & purification*
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: Fusarium/isolation & purification
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: Fusarium/isolation & purification