Diversity, mycotoxin profiles and mating populations of fusarium species associated with non-agricultural grasses in Peninsular Malaysia
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Date
2008-10
Authors
Ismail, Nor Azliza binti
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Abstract
Fusarium is a well-established pathogenic and toxigenic genus of imperfect
fungi that cause significant losses to several economically important crops and
mycotoxicoses all over the world including Malaysia. A study of Fusarium species
on non-agricultural grasses was carried out in Peninsular Malaysia to determine
the diversity of Fusarium species based on their morphological characters,
mycotoxin profiles and mating populations. A total of 304 isolates comprising 11
species of Fusarium were recovered from 67 fresh and air-dried grass samples
from 24 sampling sites in 1 0 states. The isolates were identified as F. semitectum
(96 isolates, 31.6%), F. so/ani (58 isolates, 19.1%), F. equiseti (43, 14.1%), F.
compactum (31 isolates, 1 0.2%), F. oxysporum (25, 8.2%), F. proliferatum (20
isolates, 6.6%}, F. sacchari (10 isolates, 3.3%), F. subglutinans (10 isolates, 3.3%),
F. chlamydosporum (7 isolates, 2.3%), F. nelsonii (1 isolate, 0.3%), F. lateritium (1
isolate, 0.3%), and two unidentified species that were Fusarium sp. 1 (1 isolate,
0.3%) and Fusarium sp. 2 (1 isolate, 0.3%). Four mycotoxins i.e. moniliformin
(MON), fumonisin 81 (FUMB1), zearalenone (ZEN), and beauvericin (BEA) were
detected in sterilized corn grits inoculated with conidial suspensions of 31 strains of
Fusarium species. BEA showed the highest frequency of toxin detected ( 14
strains), followed by MON (9 strains), ZEN (3 strains), and FUMB1 (1 strain). The
concentrations of BEA and ZEN were from 0.3 - 37.8 j..ll/g and 0.14 - 4.0 j.Jl/g,
respectively. Bioassays on A. salina larvae showed high mortality rates in extracts
containing MON (F. proliferatum, D3474&N; F. chlamydosporum, P3590&N),
FUMB1 (F. proliferatum, D3474&N) and BEA (F. semitectum, J3526&N; F.
oxysporum, P3610&N; F. proliferatum, 03474&N; Fusarium sp. 1, P3591&N). All
extracts with ZEN exhibited less toxicity towards the larvae. After sexual crosses
with standard tester strains, 29 field strains were found to be fertile and produced
ascospores in the perithecia while the remaining 11 strains were infertile. Three
mating populations (MPs) were recognized i.e. MP-8 (G. sacchari; 10 strains), MPD
(G. intermedia; 17 strains) and MP-E (G. subg/utinans; 2 strains). All strains of
G. sacchari carried MATB-2 allele, G. intermedia carried both MATD-1 (14 strains)
and MA TD-2 (3 strains) alleles whereas G. subglutinans carried MATE-2 allele.
This is the first report on the occurrence of Fusarium species on non-agricultural
grasses in Peninsular Malaysia.
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Keywords
Mycotoxin profiles and mating populations , Fusarium species , Non-agricultural grasses