How many fungi?

Colin A. B. Davidson cabd2 at hermes.cam.ac.uk
Wed Sep 5 10:30:21 EST 2001


"Daniel B. Wheeler" <dwheeler at ipns.com> wrote in message
news:6dafee1b.0109050559.7aaf7ee0 at posting.google.com...

> I'll take your word for it Colin. I have not studied the actinomycetes
> yet. But they sure sound similar to basidiomycetes and ascomycetes.
> Then, of course, there's the Termite mushrooms, Termitomyces... Sounds
> like the same to me.

The actimonycetes ae somewhat similar to the fungi in some ways. They're
filamentous, and the more familiar genera produce chains of spores on aerial
mycelium. They're still bacteria, though, for the simple reason that they're
prokaryotic, i.e. the cell structure, the DNA, the membranes are all
bacterial, and of course the fungi are eukaryotes.

> Of course, there's a lot of fungi I don't recognize yet. That's what
> happens when you don't get a degree in mycology, I guess.

Oh, even those people who -have- done degrees in mycology tend not to know
them all! Too many to know.

> Agreed. Certainly with as many as 60 different *varieties* of fungus
> actually being different sexual and asexual stages, coming close to a
> final total is going to be problematic. <G> And it does kind of
> presuppose one can grow or cultivate all of those forms, doesn't it?
> OTOH, DNA work certainly adds greatly to the possibilities.

It does, but even then it's hard to do good DNA work without being able to
first isolate your strain, and that means growing it (even if all you can
get is a small spot of fluff on a plate). There are various ways of doing
direct DNA isolation from environmental samples, but that in itself isn't
going to give us the whole picture.

> I suspect (only a guess here) that many bacteria may be symbiotic with
> fungi. That would explain some of the bizarre relationships present in
> the world, such Kambucha tea and chanterelles. Kambucha tea, according
> to Paul Stamets, is actually a complex intersymbiosis between two
> oolitic fungi and two bacteria. And Dr. Eric Danell has shown that
> Cantharellus cibarius forms a relationship with a bacteria: one that
> is _usually_ present, even if he is unwilling to say _always_ present
> at this time.

Quite, in the same way that we form complex relationships with microbes
(bacteria in our gut and on our skin, for ecample), and plants form complex
relationships also (for example mycorhizal associations and root nodulating
bacteria) it's fair to assume that many fungi will do likewise (we know
about the mycorhizal fungi, and we can speculate that bacteria are also
important).

> > I guess what I'm getting at is that the total fungal diversity of the
planet
> > is going to be vast, quite probably exceeding this speculative total.

> Perhaps. But is that 1.5 million figure a good starting point? Is it
> really reasonable? Extrapolation is so comparative. <G>

It's so, so hard to say. On the one hand it's an underestimate (for the
reasons stated) and on the other an awful lot of fungi have a much wider
distribution around the world than most plants do. Whereas a plant species
is limited by how far its seeds can travel, most species of fungi can
circumnavigate as spores. The result of this is that many, many species are
found globally, so the total diversity cannot be reasonably obtained by the
method quoted (ie taking the total local diversity comparative to plants,
and multiplying up to get a global figure).

The 1.5 million total is a starting point, for sure, but to say whether it's
a -good- starting point we'd need another way of generating a total for
comparison.

> I'm even more interested now in the endophytic fungi that Dr. Bill
> Dennison and others have been working with. Apparently these
> endophytic fungi offer unusual naturally occuring insecticides which
> mutate rapidly. While they _do_ kill a cell or two in the Douglas fir
> needles already tested, they also provide protection for the tree from
> insect outbreaks, such as Gypsy moth and other conifer parasites. How
> shall these fungi be labelled? How many more exist? Are the present in
> hardwood leaves as well? How exactly are they able to disperse? Is it
> totally by wind, or are there other symbiotic pathways involved?

This is news to me. What genera of fungi are these?






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