Biomedical Engineering Reference
In-Depth Information
fi lamentous fungi species, not only for the maintenance of cell wall integrity
but also for direct or indirect implications in pathotype (Madrid et al. 2003).
The interest in toxigenic
Fusarium
species is increasing worldwide due to
discovery of a growing number of naturally occurring
Fusarium
mycotoxin
particularly
Fusarium oxysporum
have practically importance as threaten
to plants Therefore, many Scientist worked on
Fusarium
virulence factor
genes in plants. Three structural chitin synthesis genes, CHS1, CHS2 and
CHS3 were identifi ed in the genome of
Fusarium oxysporum
, a soilborne
pathogen causing vascular wilt disease in tomato plant (Udiroz et al. 2004,
Yolanda et al. 2010).
Fusarium oxysporum,
the causal agent of vascular wilt
produces an array of pectinolytic enzyme including at least two exo-α-1,
4-polygalacturonase (exoPGs) have been studied by García-Maceira et al.
(2000). Disruption of cutinase gene of
Fusarium solani
f.sp.
pisi
decreased its
virulence on pea have also been reported by Rogers et al. (1994), Crowhurst
et al.
(1997). The Major endopolygalacturonase (PG) of the vascular wilt
pathogen of
Fusarium oxysporum
was secreted during growth on pectin by
10-12 isolates belonging to 7
forma speciales
have been studied by Di Pietro
et al.
(1996) and revealed that the PG locus is structurally highly conserved
for virulence in most isolates. Di Pitero et al.
(
1996) and Huertas-González
et al. (1999) have worked on chromosomal DNAs of different strains in
several formae speciales of
Fusarium oxysporum
using Gel Electrophoresis
techniques and mapped gene on the chromosomes and revealed that, the
each strain had a unique banding profi le, similarity in the banding profi le
was notice among the strains of the same
Fusarium
species. But in gene
mapping, the ribosomal RNA gene (rDNA) and putative pathogenesis
related genes encoding pisatin demethylase (PDA), and pectate-degrading
enzyme (PelA). Moreover, Roncero et al. (2000) observed that
Fusarium
oxysporum
invades its host plants through the roots and colonizes the
vascular system. It produces a great variety of cell-wall degrading enzymes
(CWDE), such as cellulases, xylanases, pectinases and proteases. Their
group has purifi ed and characterized an endopolygalacturonase (PG1),
two exopolygalacturonases (PG2 and PG3), an endoxylanase (XYL1) and
an endo pectatelyase (PL1). They isolated the following CWDE-encoding
genes: pg1, pgx4, pg5, xyl2, xyl3, prt1 and pl1. Gene expression in different
culture conditions were determined by Northern analysis. The occurrence
of these genes in different formae speciales was analyzed by Southern
analysis and PCR. They concluded that all these genes were expressed
during different stages of the interaction with the host plant indicating a
possible role in pathogenesis. Most recently, Nicolas and Antonio (2010)
has worked on targeted gene disruption is being carried out, in order to
determine the role of each gene in the pathogenicity process and
virulence
of
Fusarium oxysporum.
