Role of Pathogenic Genes of Fusarium oxysporum, Coding Cell Wall Degrading Enzymes during Wilt Infection in Plants - Biotechnology of Fungal Genes - page 261

proteases and pectate lyases. Major class of the Fusarium oxysporum genes,
which were involved in secretion of these cell wall degrading enzymes,
is summarized in Table 1.

Table 1: Major class of pathogenic gene locus of Fusarium oxysporum and their

corresponding cell wall degrading enzyme (CWDE) groups.

Gene locus CWDE group References

CHS1/2 Class V chitin synthase Udiroz Martin et al., 2004,

Yolanda et al. 2010

CHS7I/II Class V chitin synthase

FMK1/MAPK1 FMK1 encoding mitogen activated

protein kinase

Di Pitero et al. 2001, Nicolas and
Antonio 2010

PelA1 Pectate lyase Di Pitero et al. 1996, Huertas-

González et al. 1999

PelA-5 Pectate lyase

PDA Pisatin demethylase

PG1/2, PG6/7 Endo-polygalacturonase Di Pitero et al. 1998

PG8/9 Endo-polygalacturonase Di Pitero et al. 1998

Xyl Family 10 Endoxylanase Ruiz-Roldán et al. 1999

These enzymes may contribute to the degradation of the structural
barriers constituted by plant cell walls (Di Pietro and Roncero 1996, Huertas-
Gonzales et al . 1999, Ruiz-Roldán et al . 1999, García-Maceira et al. 2000). One
of the most important CWDEs in F. oxysporum is EndoPG. This is an specifi c
gene locus endo polyglycournases PG codes a endoPG, which (endoPG1)
was secreted during growth on pectin by isolates belonging to seven
different formae speciales of F. oxysporum, which included lycopersici, radicis-
lycopersici, conglutinans, tuberosi, ciceris, melonis and niveum (Di Pietro et al .
1998). These enzymes result in the depolymerization of homogalacturan,
a major component of the plant cell wall (Collmer and Keen 1986). When
inoculated onto tomato cell walls, endoPG is the fi rst enzyme activity
detected in F. oxysporum cultures (Jones et al. 1972). It was concluded that
PG1 is widely distributed in F. oxysporum , and that the PG1 locus was
structurally conserved in most isolates (Di Pietro et al. 1998). Comparative
analysis of an endoPG gene, PG1, in isolates of seven Fusarium species
indicated that this region would be very useful for phylogenetic analysis
in the genus Fusarium (Posada et al. 2000). Targeted genes encoding for the
endopolygalacturonase (endoPGs) secreted by F. oxysporum , PG1 and PG5,
has shown that these mutants having capability in virulence (Di Pietro and
Roncero 1998), and that they are not essential for pathogenesis on tomato
plants (García-Maceira et al. 2001). Endo-1,4-Xylanases are produced by a
number of plant pathogenic fungi and it has been suggested that they may
play a role during infection (Walton 1994). Xylanases act on xylan, which