Genus Cercospora in Thailand: Taxonomy and Phylogeny (with a ...

Plant Pathology & Quarantine
Fig. 8 – Illustration of morphological structures between Cercospora and Septoria. A. Cercospora
christellae (To-anun et al. 2009). B. Septoria violae-patrinii (Shin & Sameva 2002) (arrows show
the location of conidiophores inside conidiomata).
& Fr.) Mont. & Fr. (≡ Cladosporium bacilligerum)
as type species. This species was
characterized by having pigmented conidiophores,
and ellipsoid-fusiform, obclavatesubcylindric,
pigmented conidia with (0-)1(-3)septa
(basal clade, Fig. 7). The basal position
of Passalora clade indicated that species in
Passalora hold more plesiomorphic characters
or ancestral state characters than other
cercosporoid fungi clades. This indication was
also reported earlier by Stewart et al. (1999).
On the other hand, species within Pseudocercospora
s. str. form a monophyletic clade
wth 95% bootstrap support and appear as a
sister group to Stigmina clade with 60% bootstrap
support (Fig. 7). Morphologically, these
two genera are similar in having holoblastic
and terminal conidia. proliferation, as well as
obclavate to filiform-acicular with truncate
base and multiseptate conidia, However, they
differs due to the conidia of Stigmina being
verrucose, dark brown and sometimes producing
longitudinal septa, which is quite distinct
to Pseudocercospora s. str. which has
smooth and subhyaline conidia with only transverse
septation, and unthickened conidial loci
and hila. Pseudocercospora s. lat. is morphologically
highly variable, and accommodates a
wide range of cercosporoid hyphomycetes with
pigmented conidiophores and inconspicuous,
unthickened and not darkened conidiogenous
loci. It includes Paracercospora, Phaeoisariopsis,
Stigmina and Pseudophaeoramularia
(Crous et al. 2001). Crous et al. (2000) showed
Pseudocercospora s. lat. to be polyphyletic
within Mycosphaerella anamorphs, having
evolved more than once from different Mycosphaerella
holomorphs, and in several occasions
having lost the teleomorph (Crous &
Braun 2003). This complex includes genera
with single to synnematous (Phaeoisariopsis)
conidiophores, solitary or catenate (Pseudophaeoramularia)
conidia, eu- (Pseudocercospora)
or distoseptate (Stigmina), and scars
which are inconspicuous to denticle-like
(Denticularia and Semipseudocercospora), unthickened
to slightly pigmented conidia (Paracercospora)
(Crous & Braun 2003).
Within Cercospora species (Cercospora
s. str.), Crous & Braun (2003) stated the need
of a “compound species”, a species that is
formed when two or more species join together
because of indistinguishable in morphology or
genetic or physiology characteristics, named C.
apii s. lat., comprising all cercosporoid hyphomycetes
indistinguishable from the Cercospora
23