Good afternoon

Do you know what this "Pyreno" could be? In Acer leaves, surely A. monspeliensis. They are soft black dots, bulging when hydrated, tiny, which occupy the entire width of the leaf, as you can see in the photos. It doesn't look like a classic Pyreno, it probably isn't.

The asci have a curious apical apparatus, very marked, but it is inamyloid. All asci I've seen have that irregular shape on the walls, I assume they're alive, although it looks like they're not. Spores are 2-celled, with 4 large LBs, 2 per cell, and hyaline conical appendages at the ends.

Orienting myself for the spores I have gone to the genera Anisomeridium, Naetrocymbe, Lophiostoma, Vaginatispora, Lophitrema, Pseudocoleophonea and Wettsteinina, but I don't see anything like that.

These are the measurements:

Spores

(15.5) 16.1 - 17.4 (18.3) × (4.1) 4.7 - 5.3 (5.6) µm

Q = (3) 3.1 - 3.6 (4) ; No. = 38

Me = 16.7 × 5 µm; Qe = 3.4

Asci

(60.1) 60.6 - 72 (83.9) × (10.8) 11.8 - 14.5 (15.6) µm

Q = (4.2) 4.4 - 5.7 (6) ; No. = 42

Me = 67.1 × 13.3 µm; Qe = 5.1

Thank you so much.

Miguel Á. Ribes

Bernard Declercq, 29-05-2023 20:54

Re : Pyreno? 130523 779

Hi Miguel,

A photo of the asci would be very helpful here.

Are the asci swimmig in the perithecial centre? I ask this because the asci seem to have a Diaporthe-like apical ring, spores are Diaporthe-like too. So we have perhaps to look for your collection in the Diaporthales/Sordariomycetes instead of the Dothideomycetes.

Regards,

Bernard

Enrique Rubio, 29-05-2023 21:26

Re : Pyreno? 130523 779

Hi Miguel Ángel.
I think, as Bernard, says, you should look at the Diaporthales, the strongly refractive inamyloid apical apparatus and the sharply cut asci indicate this.

Enrique Rubio, 29-05-2023 21:29

Re : Pyreno? 130523 779

I think it is very important that you try to find out what the perithecium looks like by making thin sections of the leaf through it.

Enrique Rubio, 29-05-2023 21:41

Re : Pyreno? 130523 779

Maybe near Plagiostoma bavaricum?

Miguel Ángel Ribes, 30-05-2023 12:42

Re : Pyreno? 130523 779

Hi Bernard

The fifth photo shows asci in water, iki and in blue ink.

I think asci are free swimming in the perithecium. I will find in Diaporthales.

Thanks a lot

Miguel Ángel Ribes, 30-05-2023 13:05

Re : Pyreno? 130523 779

Hi Enrique

I will try to make sections now in dry-state. In fresh-state (fig. 2, 3) it is very soft and crushes.

Miguel Ángel Ribes, 30-05-2023 13:51

Re : Pyreno? 130523 779

Following the keys of these 2 papers I arrive to Plagistoma barriae, but this especies have a rostrum, smaller asci, narrower spores than mine and occurs in USA:

Leaf-inhabiting genera of the Gnomoniaceae, Diaporthales. M.V. Sogonov, L.A. Castlebury, A.Y. Rossman, L.C. Mejía and J.F. White. 2008

A systematic account of the genus Plagiostoma (Gnomoniaceae, Diaporthales) based on morphology, host-associations, and a four-gene phylogeny. L.C. Mejía, L.A. Castlebury, A.Y. Rossman, M.V. Sogonov and J.F. White, Jr. 2011.

I don't find information about L. bavaricum.

Thank you.

Alain GARDIENNET, 30-05-2023 13:51

Re : Pyreno? 130523 779

I'd missed this post. Probably a Plagiostoma cf bavaricum as Enrique suggests. But if you read Monod correctly, you can guess that there could be several distinct species on maple leaves.
In-depth studies should be carried out, as Sogonov, Meijia and Walker have been able to do in certain groups of these Gnomoniaceae.
The situation is similar for species on Euphorbia or Geranium: perhaps an updating needs to be made using molecular biology, by bringing in new species.
Alain

Miguel Ángel Ribes, 31-05-2023 10:34

Re : Pyreno? 130523 779

Thank you very much Alain

I see that it is another group in which it is necessary to deepen, including molecular studies. My samples are available to whoever is needed.

I still can't find documentation on Plagiostoma bavaricum beyond the original description of Hypospila bavarica, I would appreciate any documentation on the species.

Thank you.

 

Miguel Ángel Ribes, 31-05-2023 19:16

Re : Pyreno? 130523 779

Hi guys

I have made sections from dried material. I am not sure if the structure around de perithecium is vegetal or fungi. Anyway, it is a thin layer of angularis cells. It hasn't a rostrum.

I can try new cuts if these are not clear.

Thanks again.

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Enrique Rubio, 01-06-2023 10:27

Re : Pyreno? 130523 779

I understand that this is a very complex task which, in addition to a very fine cross-section, requires that it passes right through the ostiole. In any case, I would not be able to clarify much except to know whether it is central or lateralised. Plagiostoma s. lat. seems to be the correct genus, although Mejía et al. state that 'based on an LSU sequence, this species belongs in the
Gnomoniaceae but it cannot be placed in a genus. As Alain says, more studies would be needed to try to better define this or these species.

Miguel Ángel Ribes, 02-06-2023 22:12

Re : Pyreno? 130523 779

OK, thanks a lot Enrique

I am sure this collection, or at least in this state of maduration, has not ostiole.

Yes, I read that this belongs to Gnomoniaceae, but without a genus.

So, another species in folder aff.

Abrazos.

Enrique Rubio, 03-06-2023 20:39

Re : Pyreno? 130523 779

It is very unlikely that perithecia do not have ostioles. It is a different matter if it is very difficult to see them.

Miguel Ángel Ribes, 04-06-2023 10:33

Re : Pyreno? 130523 779

Yes, I know, perhaps it was not very mature.
 I will find it again sometime.
Thanks Enrique