Abstract:
The
plant pathogenic
Phytophthora drechsleri
is morphologically similar to some other
non-papillate
Phytophthora
spp., especially
P. melonis,
and it is difficult to discriminate
these convergent taxa. It seems that the Iranian pu
tative
P. drechsleri
isolates from
different cucurbit species have been generally misi
dentified and their characteristics do
not match with
P. drechsleri.
In order to compare these two groups, authentic
P.
drechsleri
isolates and isolates from different cucurbits wer
e assessed for morphological,
physiological (cultural, temperature relations, mat
ing type), and molecular traits.
Multiple gene genealogy analysis were performed on
regions of nuclear (ITS,
β
-tubulin,
translation elongation factor 1
α
, elicitin) and mitochondrial (cytochrome c oxidase
subunit I) gene sequences. Congruence was observed
in different phylogenetic data sets.
The present study demonstrated that putative
P. drechsleri
isolates from cucurbits and
pistachio trees were a distinct species and belonge
d to
P. melonis
. Data showed that
P.
melonis
was a homogenous species and there were no conside
rable molecular intraspecific
variations between isolates from cucurbits and isol
ates from other hosts. Design of a
molecular species-specific identification tool for
P. melonis
isolates is under investigation.
Keywords:
Internal transcribed spacer of rDNA
,
Phylogeny,
Phytophthora melonis
,
Oomycota
.
