268
andrias, 19
(2012)
starting trees and default starting parameters of
the DNA substitution model as recommended by
H
uelsenbeck
& R
annala
(2004). Trees were sam-
pled every 100
th
generation, resulting in an over-
all sampling of 50 001 trees. From these, the first
5 001 trees were discarded (burnin = 5 001). The
trees sampled after the process had reached sta-
tionarity (45 000 trees) were used to compute a
50 % majority rule consensus tree to obtain esti-
mates for the a posteriori probabilities of groups
of species. This Bayesian approach to phyloge-
netic analysis was repeated five times to test the
independence of the results from topological pri-
ors (H
uelsenbeck
et al. 2002).
Maximum likelyhood analysis (F
elsenstein
1981)
was conducted with the RAxML 7.2.6 software
(S
tamatakis
2006), using raxmlGUI (S
ilvestro
&
M
ichalak
2010), invoking the GTRCAT and the
rapid bootstrap option (S
tamatakis
et al. 2008)
with 1000 replicates.
In line with the results of molecular analyses of
a sampling that covered both all Erysiphe ITS
sequences available in GenBank and represent-
atives of all erysiphalean genera of which se-
quences were available in GenBank, trees were
rooted with E. adunca var. adunca, E. clandes-
tina, E. prunastri, and E. trinae.
3 Results
Spread of Erysiphe platani in Germany
After starting the public monitoring in Sep-
tember 2009 an earlier German record from
2007 was reported by one of the collaborators
(Baden-Württemberg, Kr. Emmendingen, Denz
lingen, Hauptstr., 22.10.2007, leg. B. M
etzler
,
teleomorph and anamorph with hyperparasite
Ampelomyces quisqualis C
es
., voucher speci-
men KR26434). The methodical documentation
of the distribution and spread from September
2009 to December 2011 showed that the fungus
was heading continuously north(east)ward. The
northernmost record in 2011, Sep. 17 is from
Arendsee in northern Sachsen-Anhalt (ca. 52.8°
latitude). The fungus progressed northward for
approximately 375 km in about two years, i.e. al-
most 190 km/year (Figs. 3a-d). All records were
found on London plane (Platanus acerifolia).
Phylogenetic analyses
The ITS sequences of the Erysiphe platani
specimens KR26134, KR26434, and KR27975
were identical, the ITS of KR29265 differed in
one bp from the others. Considering the two Ery-
siphe platani sequences available in GenBank
AF011311 differed in five bp in four loci, from the
above three specimens and in four bp in three
loci from KR29265; AF073349 differed in one bp
from KR26134, KR26434, and KR27975. LSU
sequences were identical.
The different runs of BA performed were congru-
ent with the results of the ML analysis in respect
to well-supported branchings (ML bootstrap sup-
port values greater than 58). To illustrate the re-
sults, the consensus tree of one run of the Baye-
sian phylogenetic analyses is presented (Fig. 2).
Estimates for a posteriori probabilities are indi-
cated on branches before slashes, numbers on
branches after slashes are ML bootstrap support
values.
In all analyses the Erysiphe platani specimens
formed a well-supported clade that clustered
within Erysiphe. The subgrouping of Erysiphe
platani with E. elevata, E. magnifica, and E. syrin-
gae received only weak support.
4 Discussion
Epidemic spread
The species was found for the first time in SW
Germany in the Upper Rhine Plain near Freiburg.
Together with the Upper Rhone valley/Saône val-
ley and the Belfort Gap (Burgundian Gate), the
Upper Rhine Plain forms a passage that allows
warm Mediterranean flows to advect northeast-
wards into Germany. Numerous authors think
that a great part of southern plant and animal
species entered the Rhine plain via this passage
(e.g. N
ährig
& H
arms
2003, L
enzin
et al. 2011).
This may also count for fungi such as the oc-
topus stinkhorn Clathrus archeri (B
erk
.) D
ring
(S
tricker
1955) and the Asteraceae rust Puc-
cinia lagenophorae C
ooke
(S
choller
1996), both
species native of Australia, or the vine white rot
fungus Fomitiporia mediterranea M. F
ischer
(see
the contribution by M. F
ischer
in this issue). So
did Erysiphe platani, most probably. This theory
is not only supported because of the first German
record in the Upper Rhine Plain. It is also sup-
ported by two additional observations: First, the
fungus has been widespread in the Rhone val-
ley around the lake Geneva before 2007 (B
olay
2005, F
ischer
H
uelin
et al. 2008) and secondly,
there were no records from other German states
until 2009 such as Bayern with its eastern pas-
sage, the Danube valley.
