Fungal intercellular connetions
Viruses infecting fungus, also called mycoviruses, can transmit from host to host without budding out of cells That is why some mycoviruses are devoid of budding mecanisms and some don't encode any capsid. Cell to cell transmission within hyphae is facilitated by septa which are cell wall pores allowing cytoplasm to cytoplasm exchanges. Virus trasnsmission through different hyphae is also possible by "anastomosis", a process in which two different hyphae are fusing. Anastomosis allows cytoplasmic exchange and virus transmission. Mycoviruses are also transmitted vertically by spores.
Donald L Nuss
Nat. Rev. Microbiol. August 2005; 3: 632?642