198
metabolism.” The term was later applied to other toxic fungal natural products
(Bennett and Klich 2003). Traditionally, toxigenic fungi contaminating agricultural
grains have been conventionally divided into two groups those invade seed crops
have been described as “field” fungi (e.g., Cladosporium, Fusarium, Alternaria
spp.), which reputedly gain access to seeds during plant development, and “storage”
fungi (e.g., Aspergillus; Penicillium spp.), which proliferate during storage (Legan
2000). Currently, this division is not so strict because according to Miller (1995)
four types of toxigenic fungi can be distinguished: (1) plant pathogens as Fusarium
graminearum and Alternaria alternata; (2) fungi that grow and produce mycotoxins
on senescent or stressed plants, e.g., F. moniliforme and Aspergillus flavus; (3) fungi
that initially colonize the plant and increase the feedstock’s susceptibility to contamination after harvesting, e.g., A. flavus; and (4) fungi that are found on the soil or
decaying plant material that occur on the developing kernels in the field and later
proliferate in storage if conditions permit, e.g., P. verrucosum and A. ochraceus.
The involvement of Aspergillus spp. as plant pathogens has been reported, and
aflatoxin- infected crops have from time to time been returned to agricultural soils.
This practice may prove hazardous, since both A. flavus and A. parasiticus can
infect crops prior to harvesting (Lillehoj and Zuber 1973). The phytotoxic effects of
the aflatoxins have been investigated, with respect to seed germination and the inhibition of root and hypocotyl elongation (Llewellyn et al. 1984; McLean et al. 1992).
Aflatoxin has been reported to occur within apparently healthy, intact seeds which
suggest that the toxin can be transported from contaminated soil to the fruit
(Anderson et al. 1975). Aflatoxin B1 (AFB1) can be translocated from the roots to
the stems and leaves. If the soil microorganisms do not rapidly degrade the aflatoxin
contained within the plowed under stover and grains, the possibility that the roots of
the seedlings of the following year’s crop will both absorb and translocate the aflatoxins to both the stems and leaves exists (Mertz et al. 1980). This could be hazardous to the plant’s growth and development as well as to the consumer’s health. The
Penicillium genus dominated the fungal flora, with mycotoxigenic species such as
P. crustosum, P. chrysogenum, P. hirsutum, P. expansum, P. roqueforti, P. viridicatum, P. commune, P. aurantiogriseum, P. citrinum, P. verrucosum, P. cyclopium,
P. canescens, P. madriti, P. palitans, P. thomii, P. baarnense, P. fenneliae, and P. frequentans. These fungi have been reported to produce a number of toxins as citrinin
(CTN), cyclopiazonic acid (CPA), ochratoxin A (OTA), patulin (PAT), penicillic
acid (PA), penitrem A (PNT), roquefortine (RQF), frequentin (FRE), palitantin
(PAL), mycophenolic acid (MPA), viomellein (VIM), gliotoxin (GT), citreoviridin
(CIV), and rubratoxin B (RB) (Frisvad and Filtenborg 1983; Frisvad and Thrane
1996; Frisvad and Samson 2004; Yamaji et al. 2005; Ismaiel and Papenbrock 2014).
These fungal species and their mycotoxins contaminate harvested seeds causing
losses of agricultural commodities in many zones of the world. Such contaminants
are fearsome, since they affect the seeds before harvest time and may find optimal
developing conditions when the seeds are stored, leading to alteration of the germination quality of these seeds (Koteswara Rao et al. 2014). Alternaria,
Helminthosporium, Pyrenophora (sexual state: Drechslera), Phoma, and
Zygosporium are genera of saprobic and plant pathogenic dematiaceous fungi with
N. M. Abdelmotilib et al.
metabolism.” The term was later applied to other toxic fungal natural products
(Bennett and Klich 2003). Traditionally, toxigenic fungi contaminating agricultural
grains have been conventionally divided into two groups those invade seed crops
have been described as “field” fungi (e.g., Cladosporium, Fusarium, Alternaria
spp.), which reputedly gain access to seeds during plant development, and “storage”
fungi (e.g., Aspergillus; Penicillium spp.), which proliferate during storage (Legan
2000). Currently, this division is not so strict because according to Miller (1995)
four types of toxigenic fungi can be distinguished: (1) plant pathogens as Fusarium
graminearum and Alternaria alternata; (2) fungi that grow and produce mycotoxins
on senescent or stressed plants, e.g., F. moniliforme and Aspergillus flavus; (3) fungi
that initially colonize the plant and increase the feedstock’s susceptibility to contamination after harvesting, e.g., A. flavus; and (4) fungi that are found on the soil or
decaying plant material that occur on the developing kernels in the field and later
proliferate in storage if conditions permit, e.g., P. verrucosum and A. ochraceus.
The involvement of Aspergillus spp. as plant pathogens has been reported, and
aflatoxin- infected crops have from time to time been returned to agricultural soils.
This practice may prove hazardous, since both A. flavus and A. parasiticus can
infect crops prior to harvesting (Lillehoj and Zuber 1973). The phytotoxic effects of
the aflatoxins have been investigated, with respect to seed germination and the inhibition of root and hypocotyl elongation (Llewellyn et al. 1984; McLean et al. 1992).
Aflatoxin has been reported to occur within apparently healthy, intact seeds which
suggest that the toxin can be transported from contaminated soil to the fruit
(Anderson et al. 1975). Aflatoxin B1 (AFB1) can be translocated from the roots to
the stems and leaves. If the soil microorganisms do not rapidly degrade the aflatoxin
contained within the plowed under stover and grains, the possibility that the roots of
the seedlings of the following year’s crop will both absorb and translocate the aflatoxins to both the stems and leaves exists (Mertz et al. 1980). This could be hazardous to the plant’s growth and development as well as to the consumer’s health. The
Penicillium genus dominated the fungal flora, with mycotoxigenic species such as
P. crustosum, P. chrysogenum, P. hirsutum, P. expansum, P. roqueforti, P. viridicatum, P. commune, P. aurantiogriseum, P. citrinum, P. verrucosum, P. cyclopium,
P. canescens, P. madriti, P. palitans, P. thomii, P. baarnense, P. fenneliae, and P. frequentans. These fungi have been reported to produce a number of toxins as citrinin
(CTN), cyclopiazonic acid (CPA), ochratoxin A (OTA), patulin (PAT), penicillic
acid (PA), penitrem A (PNT), roquefortine (RQF), frequentin (FRE), palitantin
(PAL), mycophenolic acid (MPA), viomellein (VIM), gliotoxin (GT), citreoviridin
(CIV), and rubratoxin B (RB) (Frisvad and Filtenborg 1983; Frisvad and Thrane
1996; Frisvad and Samson 2004; Yamaji et al. 2005; Ismaiel and Papenbrock 2014).
These fungal species and their mycotoxins contaminate harvested seeds causing
losses of agricultural commodities in many zones of the world. Such contaminants
are fearsome, since they affect the seeds before harvest time and may find optimal
developing conditions when the seeds are stored, leading to alteration of the germination quality of these seeds (Koteswara Rao et al. 2014). Alternaria,
Helminthosporium, Pyrenophora (sexual state: Drechslera), Phoma, and
Zygosporium are genera of saprobic and plant pathogenic dematiaceous fungi with
N. M. Abdelmotilib et al.