I am using kit for direct isolation of DNA from soil samples. However, I am unclear whether the origin of these DNA sequences are expected to be fungal or not, since primers were from ITS regions.
There are many commercial kits for soil DNA like NKG-T026. In this kit, innovative extraction and lysis system allow for rapidly lysing cells and inactivating cellular nuclease. If soil samples containing humic acid and inhibitors of PCR, you can use NKG-T049. This kit has been successfully used to isolate DNA from fungi, and soil microorganisms that inhabit a range of samples including clay, sandy, peaty, chalky, and loamy soil samples. Also, there are many kits produced by Zymo Research.
There are many commercial kits for soil DNA like NKG-T026. In this kit, innovative extraction and lysis system allow for rapidly lysing cells and inactivating cellular nuclease. If soil samples containing humic acid and inhibitors of PCR, you can use NKG-T049. This kit has been successfully used to isolate DNA from fungi, and soil microorganisms that inhabit a range of samples including clay, sandy, peaty, chalky, and loamy soil samples. Also, there are many kits produced by Zymo Research.
Thank you for your suggestion, I need to isolate Plasmodiophora brassicae using ITS regions. Is this region will be enough for isolating particular fungi from the soil sample or any other protocols should be followed to avoid other fungi from the same sample?
In virtually every case you have to know the DNA you are seeking. For example, you can start your search here for your strain or the family: http://www.cbs.knaw.nl/Collections/
The ATCC used to sell fungal & bacterial strains. I am not sure they are still out there. But these are:
If you are thinking to find a DNA from one organism in among many in a sample... that is not possible without knowing which you are seeking and then finding either the method or having the sequence to work selective media culture from.
Selective medias work fairly well to isolate one strain/culture from many. Try this publication: https://www.boundless.com/microbiology/textbooks/boundless-microbiology-textbook/culturing-microorganisms-6/culturing-bacteria-58/selective-and-differential-media-366-6910/