Hi everyone,
In my dual culture assay, I noticed a yellow pigment secreted by Trichoderma harzianum in PDA at 10°C but not in 4°C and 15°C (pictures attached). Can someone please tell me if this is normal or contamination? I am trying to understand what exactly is this yellow pigment. I am currently running this experiment and a quicker response is appreciated.
FYI, the dual culture assay is being performed to examine if the T. harzianum can suppress the growth of Botrytis cinerea at different temperatures.
Sometimes Trichoderma harzianum growing especially on PDA may give shades of yellow, green or white and or a yellow pigment may be secreted into the Potato dextrose agar.
There are chances of contamination too because sometimes Trichoderma ressei starts growing in cultures of T. harzianum. Please check its morphology through microscope.
Trichoderma secretes brwon colored pigment furfural. it may be the reason of this color
Hi Basanti
The color is a pigmentation and characterization for species
But the pigmentation is changing according type of media and degree of temperature, this is a physiological reaction
Yes. Dr. Laith, secondary metabolites secreted in medium and may change the color
A big thanks to everyone for answering my question. It was really helpful.
Hi, Most fungus produce pigments on medium, its a secondary metabolite and the pH of the medium is one of the factors that control the color.
Trichoderma Longibrachiatum , T. atroviride, T. virens, T. reesei secretes a typical yellow pigment (secondary metabolites) during growth; especially on PDA.
Sorbicillinoids are a group of yellow secondary metabolites that are produced by a range of Trichoderma. Many of these hexaketide metabolites are highly oxygenated and have complex bicyclic and tricyclic frameworks. However, their name-giving, common feature is an apparent similarity of their core structures to sorbicillin.
https://www.aua.gr/~coulad/projects/bms/BMS.html
Depending on the conditions of cultivation the "green" Trichoderma strains may have yellow pigmentation.
The green coloration is the pigment associated with the condia.
The yellow pigment is in the medium and is a secreated secondary metabolite.
Yellow pigment in the medium is common in uncontaminated cultures of many Trichoderma spp.
Observe the pigmentation as it relates to the dual culture and keep an eye of anything different.
For instance does the pigment increase or decrease in different dual cultures
Yes, it's normal that Trichoderma harzianum produces yellow pigment on the medium, it's considered as secondary metabolites of this fungus, while the green color refers to conidia color. So, you must be quiet that it's not contamination.
Trichoderma harzianum, T. hamatum, T. koningii, T. pseudokoningii produce green color conidia on the media, while T. viride and T. atroviride produce yellow conidia on the media. There are two types of pigmentation, one of them belongs to the conidia color, while the other belongs to the secondary metabolites that secreted by the fungus itself.
The shapes of colonies, conidia and phialides are the main parameters to distinguish and diagnose the species of the genus Trichoderma. Some phialides are short while others are long. Some conidia are globose while others are elongate. Also, some conidia are smooth, others are rough.
Now I see a yellow pigment in the colonies of Trichoderma harzianum and T. longibrachiatum growing on PDA medium in my laboratorial experiments. I am sure that they are pure and not contaminated, but they have secreted yellow pigmentation.
With kind regards!
If you want to identify Trichoderma spp., you must grow the fungus on OA (Oatmeal Agar) medium at 20 C. You can use 30 gm of Oat meal, 20 gm of Agar and one liter distilled water. Autoclaved at 121 C and 15 pounds/inch2 for about 30 minutes.
Could there be instance where Trichoderma spp produce both green and yellow pigment at the same time?
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