Can truffles reproduce asexually?


black truffle asexual stage,  truffles conidia production

black truffle asexual stage, truffles conidia production

Many fungi have besides a sexual phase, another parallel asexual or anamorphic stage, which are able to produce asexual spores or conidia, that may act as dispersion units. These mitotic conidia (simply dividing by mitosis) have been described for Tuber borchii, T. dryophilum and T. maculatum group. In fact, “spore mats” have been found in 9 of the 16 lineages of Pezizales. So why not the other truffles could have them? These conidia are 1 / 3-1 / 5 of the meiospores size that is in the fruiting body of truffles, in some cases 1 micron compared to the 40 microns meiospores, and they are easier to spread by water or wind and facilitate that different genets and mating types meet and fruit. Likewise, they may act as spermatia (parts necessary for fertilization in sexual reproduction), for example these conidia would be produced on the surface by the mycelium and may be carried elsewhere (wind, arthropod or other animals) and in contact with the hyphae emerging from a mycorrhiza of “mating type”, may form the dikaryotic mycelium, the only one able to produce truffle fruit bodies.

truffle spores mats from Healy.

truffle spores mats from Healy.

You can already start looking under clods of soil from your truffle orchard, small clusters of white hyphae, about one square centimeter size, and looking at them with magnifying lens look like dusty, like the image attached from Rosanne Healy paper.

The picture that heads this post is part of the new book we are about to publish about truffles and their cultivation (will keep you posted). Here you can see like any mycelium, in this case positive sex, may form conidia that once germinated, the new hyfa (also positive) when meeting another complementary type mycelium, for example, coming from a mycorrhiza (negative sex in the illustration) give rise to dikaryotic mycelium, the one able to form a fruit body.

We now know that several fungi excrete hydrophobins to create a liquid film around the mycelium that make easier for bacteria and possibly their own conidia to move on the ground. They are in fact the “highways” (without tolls 🙂 or “skating ice rink ” along which various substances move at speeds around 1 cm per day.

We do not know whether these conidia are able to form mycorrhiza, therefore in one of the papers I cite below, none of the spore mats used as mycorrhizal inoculum produced any mycorrhiza under controlled conditions.

If in the near future, we can grow these mitospores inoculum in the laboratory and produce them cheaply, a tremendously interesting truffle door would open.
As a practical conclusion, a soil with a high activity of insects or animals, can favor the spread of mycelia, conidia or spores of different mating types to favor fruiting, also farmers can help with a single tilling.

Cheers,

Marcos S. Morcillo

References:

– Urban A, Neuner-Plattner I, Krisai-Greilhuber I, Haselwandter K. 2004. Molecular studies on terricolous microfungi reveal novel anamorphs of two Tuber species. Mycological Research 108: 749-758

– Healy RA, Smith ME, Bonito GM, Pfister DH, GE ZW, Guevara GG, Williams G, Stafford K, Kumar L, Lee T, Hobart C, Trappe J, Vilgalys R, Mclaughlin DJ (2012) High diversity and widespread occurrence of mitotic spore mats in ectomycorrhizal PezizalesMolecular Ecology22, Issue 6, pp 1717-1732Doi: 10.1111/mec.12135.

– Rosanne Healy. Fungal Diversity…Hiding in Plain Sight. THE MYCOPHILE, JULY-AUGUST 2014. http://harvard.academia.edu/rosannehealy

About trufflefarming

CEO of Micofora. Truffles and edible wild mushroom science and farming. Researcher, truffle farmer & mycologist
This entry was posted in spanish truffle orchards, truffle books, Truffle farming, truffle growing, truffle nurseries, truffles and bacteria and tagged , , , , . Bookmark the permalink.

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