Hi all,
I thought some of you might be interested to hear about my progress. Last year, huitlacoche appeared in my garden spontaneously, growing out of the tassels of my Hopi Blue corn. I took a tissue culture from the fresh huitlacoche, and isolated it on MEA. I also saved some spore-laden galls as a backup and a larger genetic pool in case I needed it.
This year I decided to intentionally inoculate my corn with LC. I decided to brew up the LC in my 1600mL air-lift bioreactor. This is a first prototype/proof-of-concept that I developed over the winter, and which has been effective and lots of fun, although its capacity isn’t much greater than an ordinary quart jar of LC. I’d be happy to post more about this reactor, the build, how it works, and its many limitations and areas for improvement if anybody is interested. It is 100% autoclaveable, so I’m able to load it up with nutrient media, and then sterilize the whole thing in my 23qt Presto. Here it is right before sterilizing:

Here’s the Air-Lift BioReactor (ALBR from here on out) filled with 1.6L of 4% dextrose solution, sterilized and ready to inoculate. I really cooked the shit out of the dextrose:

I inoculated the ALBR using a micro-batch of LC derived from the culture on agar that I’d isolated last year. 5 days after inoculating the ALBR, I had plenty of growth, so I filled a 50mL Luer-lock syringe with LC and inoculated some cobs. I tried the basic method that AndyHinton suggested, and squirted a few cc of liquid culture down the ears of cobs that were just starting to show silks.
Here’s some of the LC under the microscope. You can see U. maydis cells, including what appear to be filamentous cells, indicating dikaryotic growth - a good sign! Does anybody have any idea what the needle-like structures could be?

Anyway, after I’d inoculated the corn, I kept an eye on my corn patch for any signs of smut, but didn’t see anything in the first couple weeks and pretty much forgot about it. By day 27 after inoculation, I still hadn’t seen any huitlacoche bursting out of the husks. I decided to try and harvest a cob or two to see if there was any growth under the husk:

Success! I couldn’t believe it. I harvested 3 of the cobs which I thought I remembered inoculating, and 2 of them were thoroughly smutty. Next year I really need to mark cobs as I inoculate them so I remember which ones have been treated. I have a bunch of new baby ears of corn out in the patch, so I inoculated a bunch more after this.

I made quesadillas with the harvest - not bad at all! Corny, mushroomy, vaguely “smoky.” One of these cobs was slightly bitter, which apparently happens as the smut ages, so perhaps I let it go too long.
Overall, I’m very pleased, and will definitely be revisiting this experiment in future years. I’m particularly interested in trying to inoculate by simply spraying the young cobs with LC out of a backpack sprayer. With a much larger ALBR to prep the LC, this could be a relatively cost-effective way to inoculate whole fields with a known pathogenic strain of U. maydis.
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