Molecular Basis of Symptom Expression by the Cryphonectria Hypovirus

Major impacts on the primary metabolism of the plant pathogen Cryphonectria parasitica by the virulence-attenuating virus CHV1-EP713

“…The lack of development in a hypovirus-infected colony (as noted by reduced pigmentation and asexual sporulation) has been likened to retaining the mycelium in a juvenile state (McCabe & Van Alfen, 2001). This is supported by our data showing that the presence of the hypovirus partially prevented metabolic changes characteristic of older, uninfected, fungal tissue.…”

Effect of Cryphonectria hypovirus 1 (CHV1) infection on Cpkk1, a mitogen-activated protein kinase kinase of the filamentous fungus Cryphonectria parasitica

“…Since then connections have been sought between the virus and various components of the host's signal transduction pathways particularly in relation to developmental processes. The possible role of G-protein regulated cAMP levels was thoroughly investigated (Choi et al, 1995;Chen et al, 1996;Nuss, 1996;Kasahara and Nuss, 1997), but, to date, a direct biochemical inXuence or interaction of viral infection on heterotrimeric G protein components in C. parasitica has not been shown; moreover, signiWcant diVerences in the way the above mentioned signal transduction components are perturbed by two equally hypovirulent viral strains (Parsley et al, 2002) seem to suggest that hypovirulence caused by CHV1 has other targets, possibly including viral perturbation of host protein secretion (McCabe and Van Alfen, 1999;McCabe and Van Alfen, 2001). Recently cppk1 a gene encoding for a Ser/Thr protein kinase of C. parasitica was shown to be transcriptionally up-regulated in a virus infected strain (Kim et al, 2002).…”

“…The type member of this family, Cryphonectria hypovirus 1 (CHV1)-713 has little adverse eVect on host growth rate, but perturbs fungal developmental processes such as asexual and sexual sporulation, and virulence expression (McCabe and Van Alfen, 2001;Nuss et al, 2001;Dawe and Nuss, 2001).…”

Mycovirus Cryphonectria Hypovirus 1 Elements Cofractionate with trans -Golgi Network Membranes of the Fungal Host Cryphonectria parasitica

“…CHV1 is a member of the virus family Hypoviridae, distinguished by the ability to attenuate virulence and alter developmental processes upon infection of the fungal host. Specific symptoms of virus infection of the fungus grown in culture include reduced pigment production, suppressed asexual sporulation, loss of female fertility, and modified expression of specific host genes (27,29,39,40).CHV1 has a double-stranded RNA (dsRNA) genome and, like other fungal virus dsRNAs, that of CHV1 is not infectious but can be transmitted horizontally by fungal anastomosis (38) and vertically through asexual, but not sexual, spores. Although hypovirus RNA is found in hyphal extracts as dsRNA, the structural characteristics of the dsRNA are reminiscent of a replicative intermediate or replicative form of a singlestranded RNA (ssRNA) virus (53).…”

“…CHV1 is a member of the virus family Hypoviridae, distinguished by the ability to attenuate virulence and alter developmental processes upon infection of the fungal host. Specific symptoms of virus infection of the fungus grown in culture include reduced pigment production, suppressed asexual sporulation, loss of female fertility, and modified expression of specific host genes (27,29,39,40).…”