Well its a normal phenomenon, any metabolically acceptable mineral in low or adequate amount will be useful and its excess amount will be bad e.g. hypercalcemia in our body etc. Same is the case for fungi too.

Well about higher (filamentous) fungi, people have not studied the affect of NaCl much, but to the level of yeast, especially on halophilic yeast there are publications available particularly on Hortaea werneckii, Saccharomyces cerevisiae, etc. Mostly the high salt creates the low water activity in the cells of fungi which slows down the flow of transportation in and outside fungal cells. In halophilic yeast some bio-compatible solutes helps to maintain the balance of materials inside and outside yeasts. 

I am working on obligate halophilic fungi, which cant grow without NaCl, and quite a high concentration helps their metabolic machinery such as enzymes. These come out to be more interesting case than normal halophilic organisms. We are still working to see how they do so.

I hope I have answered a bit of your query.

Dear Kartikeya,

The mechanisms may be quite different, depending on species and ecological features of the fungal organism

We study NaCl and pH effect to filamentous fungi.. you may see following publications provided by me and my colleagues

Article Sodiomyces alkalinus, a new holomorphic alkaliphilic ascomyc...

Article Are alkalitolerant fungi of the Emericellopsis lineage (Bion...

Article On the diversity of fungi from soda soils

Article Heleococcum alkalinum a new alkali-tolerant ascomycete from ...

And one more:

Article [Effect of sodium chloride concentration in the medium on th...

Thank you Imran sahib for the information. I went through your research papers and they were very helpful. Thank you!

Thank you Maria, yet again, for the papers! They have been extremely helpful. Thanks a tonne!

ur guidance is helpfull for my student write desertation thanx...