Dear Gerrit,
You are correct my first language is German.
Your next project sounds very interesting to me. I have carried out field and
glasshouse experiments utilising endo and ectomycorrhizal fungi, innoculated
onto trees, in order to examine multitrophic interactions, biomass and inter
specific fungal competition. I had not considered the time required to allow
the tree "establish" before it could "afford" sugars. I will review my paper
again, this may explain an unexpected result.
Regards
Freidrich
________________________________
From: Viper Snake <snake24@xxxxx.nl>
To: UK Tree Care <uktc@xxxxxx.tree-care.info>
Sent: Friday, 23 December 2011, 16:12
Subject: RE: Ganoderma applanatum/australe on n.maple - implications
Dear Freidrich,
I assume your native language is German, not Dutch like David assumes.
1) ... biotoof ...
1) In Dutch, it is always spelled biotroof.
2) I also find interesting the use of the term biotrophic parasite. I had not
thought in these terms previously, my experience has been largely with
mutualism and symbiosis. I have read however that such associations exist on
a continuum of benefit depending largely alterations in environmental factors
and may sometimes move towards parasitism. Though not proven it would be
reasonably deduced that should the environmental conditions be restored
mutualism would once more prevail. This may make an interesting area of
research.
2) Next year, I'll start a research project (Wageningen University) on
facultative ectomycorrhizal macrofungi such as Scleroderma citrinum, Paxillus
involutus, Thelephora terrestris and Boletus badius, that do not seem to have
lost their capacity to (temporarely) live as a saprotroph on and fruit from
dead wood while "awaiting" to colonise the roots of a new partner and seem to
refrain from retracting sugars for producing fruitbodies from the seedling
and young tree partner until the tree can "stand on its own feet" by
developing the foliage needed to produce enough energy (reserves) through
photosynthesis to support itself and its tree species specific ecosystem, and
can "afford" sharing the sugars with its symbionts, the mycelia need to fruit.
Regards,
Gerrit
Without wanting to complicate things any further, some citations on
biotrophic and necrotrophic parasitic macrofungi from Scandinavian and Dutch
literature and my own experience, I would like to have your opinion on,
follow.
- The (biotrophic) parasitic Inonotus hispidus, that grows "on living
hardwoods" and "dies with the tree" (my words), "is capable of killing
sapwood (soft rot) in living trees" (Ryvarden & Gilbertson, European
Polypores I).
- In my experience, the same thing applies to Inonotus cuticularis on Fagus
and to Meripilus giganteus on Fagus and the 16 other tree species it is this
far documented from, of which the mycelia of both species also invade and
cause a soft rot of living tissues.
- The (biotrophic) parasitic Phellinus tremulae "spreads in the inner sapwood
and inner wood of living trees in the absence of other organisms, indicating
that it is a primairy parasite in aspen" (Wickström in : Ryvarden &
Gilbertson, European Polypores II).
- And is Pholiota squarrosa obligate (biotrophic) parasitic or - according to
Arnolds, et al. : Overzicht van de Paddestoelen in Nederland - necrotrophic
parasitic, as it dies with the tree and never fruits from dead wood alone,
which is very exceptional for parasitic Agaricales ?
So how would you label these macrofungi, as obligate (biotrophic) parasitic
or necrotrophic parasitic ?
biotroof - food withdrawing to live parts of a host.
I think that this simply means that the parasite is obtaining its food from
living tissues. This is okay as a literal translation of the original
Greek: "bios" = life / "trophe" = food. I do not, however, think that this
definition is precise enough to distinguish between a biotroph and a
necrotroph (just as you implied in your previous message).
In Ainsworth and Bisby's Dictionary of the Fungi (8th edition, CAB
International), the definition of biotroph is as follows:
"Biotroph: an obligate parasite growing on another organism, in intimate
association with its cytoplasm."
I think that the Ainsworth & Bisby definition means almost the same as the
one that I wrote yesterday. I did not, however, use the word "obligate"
(meaning that the parasite can grow only on the living host; not on a
non-living culture medium), because I am aware of a few rust fungi (for
example) that have been grown on artificial media, with great skill and
difficulty. On the other hand, it is quite useful to use the word
'obligate', since this clearly shows that wood decay fungi cannot be
biotrophic according to the strict definition. They must either be
necrotrophic parasites (if they invade and kill living tissues) or
saprotrophs (if they grow only in tissues that are already dead).
I use the definitions from this list (in Dutch) (
www.springerlink.com/content/tuj653216XXXXXXX ) and to add some more
information on the subject of tree species specific strategies of parasitic
macrofungi being part of and co-evolved within a tree species specific
ecosystem (Keizer, 2007/2011), the following on the tree species colonised
by Fomitopsis pinicola on the European continent.
I hadn't realised the use of "biotrophic" and "necrotrophic" were
differently in the UK and on the continent; thanks for mentioning this.
I don't know whether other UKTC members share my unease about identifying
species of Ganoderma in the field. I would feel happier if each species
could be shown to have a distinct combination of characteristics (including
hyphal structure, average spore-size, DNA-based criteria, thickness and
hardness of the crust and the presence/absence of insect-galls). Perhaps we
are wrong in the UK to be identifying a large proportion of the Ganoderma
on beech as G. australe/adspersum. Various fungi do, however, show
genuinely different frequencies of occurrence between the UK and parts of
the near continent. For example, we seem to have more G. pfeifferi here.
Also, Fomes fomentarius is much less frequent on beech (and on other tree
species) in southern Britain than on the continent. It is more common in
northern Britain, where the main host is birch.
-----Original Message-----
From: Viper Snake [mailto:snake24@xxxxx.nl]
Sent: 21 December 2011 19:33
To: UK Tree Care
Subject: RE: Ganoderma applanatum/australe on n.maple - implications
Dear David,
Although there is quite a difference in your definition of biotrophic
and necrotrophic parasites and the definition of both terms on the
continent, as is included in all Dutch, German and Scandinavian
literature I refer to, I consider your definition to be the more
precise.
And after always microscopically assessing what perennial species of
Ganoderma I found on beech in The Netherlands and Germany, I have come
to the conclusion, that about 95 % of perennial Ganoderma species on
beech is G. lipsiense, followed by the rare G. pfeifferi and the
extremely rare G. australe.
Regards,
Gerrit
From: d.lonsdale2@xxxxxxxxxxx.com
To: uktc@xxxxxx.tree-care.info
Subject: RE: Ganoderma applanatum/australe on n.maple - implications
Date: Wed, 21 Dec 2011 18:29:51 +0000
Dear Gerrit,
In answer to your question, I define the relevant terms as follows:
1. Biotrophic parasite: a parasite which obtains its nutrients from
the living cells of the host (usually by the penetration of those
cells, without killing them). Examples include rusts and mildews.
2. Necrotrophic parasite: a parasite which obtains its nutrients by
killing cells of the host (usually by the secretion of enzymes and/or
toxins). These parasites are usually able to grow also as saprotrophs
(4, below) and they are therefore often alternatively called
"facultative parasites". Examples include many fungi and bacteria
that cause general dieback and/or decay of host tissue.
3. Hemibiotrophic parasite: a parasite which obtains its nutrients
both as a biotroph (usually when it first penetrates host tissue) and
as a nectroph (usually at a later stage, after an initial biotrophic
phase). Examples include many organisms that cause leaf spot diseases.
4. Saprotroph: an organism which obtains its nutrients from the dead
remains of one or more living organisms.
As far as I know, there are no wood decay fungi in categories (1) or
(3) above. Some of them have the ability to grow into previously
living sapwood, causing it to die (or become "dysfunctional" and then
causing decay. I think that they can be regarded as necrotrophic
parasites (2), but I do not like to use this term without
qualification, since many of them live predominantly on wood that is
already dead. This could be sapwood that has been damaged by injury,
or it could be central wood or the tree, which has become heartwood
or ripewood because of aging.
Traditionally, wood decay fungi have been described as "parasitic" if
they are found on living stems, branches or roots. I do not think
that this is correct if the fungus concerned is colonising only wood
that is already dead.
According to the above definitions, Ganoderma applanatum has been
observed to be mostly saprotrophic, whereas G. adpsersum/australe has
some capacity to act as a necrotrophic parasite. These observation
seem to be confirmed by some experimental work by my friends Schwarze
& Ferner at the University of Freiburg i. Br., Germany. (see:
http://www.enspec.com/articles/ENSPEC%20Research%20Paper%20-%20Ganoderma%20on%20Trees.pdf
)
Schwarze & Ferner found that G. adpsersum/australe was able to
penetrate defensive barriers (reaction zones), thus growing into
functional sapwood. It does not necessarily harm the tree seriously.
Instead, it might be able to co-exist with the tree for many years,
instead of dying out when it has utilised all the wood that was
initially available to it. In some cases, however, the fungus does
enough damage to the sapwood (especially in the roots of the tree) to
cause the decline and perhaps death of the tree. Also, the decay can,
in my experience, become overwhelmingly rapid if the wood becomes
more aerated because of excessive pruning or the storm-breakage of
major branches.
As suggested in the recent correspondence, G. adpsersum/australe
appears to behave differently in different host species. I think that
it can be especially aggressive in species with which it has not
co-evolved. I have seen examples where G. adspsersum/australe (or
perhaps a similar-looking species of Ganoderma) seems to have killed
exotic conifers such as Araucaria araucana. I agree that it can cause
extensive decay in the broadleaved trees in your list. However, in
Fagus sylvatica (one of its main hosts in the UK), the tree and the
fungus often seem to co-exist for many years. The co-existence is
probably even longer in species like Quercus robur and Q. petraea,
which have durable heartwood and therefore tend to become decayed
more slowly.
Regards,
David
-----Original Message-----
From: Viper Snake [mailto:snake24@xxxxx.nl]
Sent: 21 December 2011 14:14
To: UK Tree Care
Subject: RE: Ganoderma applanatum/australe on n.maple - implications
David,
1). Tony Croft has been using the term 'biotrophic parasite' in
relation to G. adspersum/australe on here. I questioned him about
these labels and asked him whether he could point me to any research
that demonstrated that the fungus was 'biotrophic' and/or
'parasitic', because this was news to me, but he hasn't replied yet.
Can you point me in the right direction?
1). Tony uses my terms and the results of my in situ research on
biotrophic and/or necrotrophic parasites, which I already have
explained on Arbtalk, see : 2.
http://arbtalk.co.uk/forum/529703-post53.html .
2). Similarly, that G. adspersum/australe is deterministically fatal
to Acers, no matter the circumstances, is also news to me. Where does
the research for this conclusion come from ?
2). From my own field research on the effects on the stability and
condition of different deciduous tree species of the biotrophic
parasitic G. australe, of which the mycelium causes a white rot with
selective delignification, that is most detrimental to Acer,
Platanus, Populus, Salix, Tilia, Aesculus (Anne Frank tree) and
Quercus rubra.
Gerrit
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