Yes, there might be explanation and it might be just a bacterial contamination. Check it under the microscope and you will know.

Hi Aline,

you isolated from a Rhizome; so there is a big chance for bacterial contamination. you can prepare Czapeks medium with chloramfinicol antibiotic and subculture your Fusarium and I think you will not see these shiny colonies again which mean thatt hey are just bacterial colonies.

For sure the apperance of the bacterium colony is a contament. I recomend to add a wide spectrum antibiotic .Good luck.

It also is possible for Fusarium to have a pionotal mutation (see section on

"degenerate cultural variants" in Leslie and Summerell 2006 or Toussoun & Nelson 1975 or 1976)) which leads to reduced aerial mycelium and a moist appearance. If this is the case, there will be a profusion of macroconidia over the surface of the colony. It is not infrequent to see sectoring with these types of variants, particularly if growing/maintaining the fungus on a high nutrient medium like potato dextrose agar or complete medium. If this is the case, single spore or hyphal tip transfers should be made from a non-degenerate part of the colony to a better medium for maintenance of Fusarium.

Hi Aline,

In my opinion, there is a big chance for bacterial cross-contamination in your media if you did not use an antibiotic in fungal media preparation. So, in an agreement with Dr. Samah referring for chloramphenicol as an effective antibiotic against bacteria growth, you can also use any broad-spectrum antibiotic to ensure bacterial growth suppression.

One more point, that you can take an isolate to agar-water media which is simple in preparation and dominantly use for Fusarium isolation. So, if it was a bacterial strain, this media will be unsuitable for its growth.