Project description:Infection of the chestnut blight fungus, Cryphonectria parasitica, by hypovirus CHV1-EP713 or by reoviruses MYRV1-Cp9B21 or MYRV2-CpC18 results in reduced fungal virulence (hypovirulence). However, additional phenotypic changes caused by the two groups of mycoviruses are quite different. CHV1-EP713 infection results in depressed pigmentation and conidiation while reovirus infection has little effect on these processes. We now report that loss of female fertility and resulting absence of virus transmission through sexual spores observed after hypovirus infection was not observed for reovirus infected C. parasitica. Reovirus-infected strains were male and female fertile and able to transmit virus to ascospore progeny at a high rate when serving as a female parent. Consistent with this result, real-time RT-PCR revealed that expression of two genes involved in sexual reproduction, the pheromone precursor gene, mf2-1 and yeast Ste12-like transcriptional factor gene, Cpst12, were less reduced in reovirus-infected strains than in hypovirus-infected strains. Analysis with a custom microarray cDNA chip containing EST clones representing ca 2,200 unique C. parasitica genes identified 140 and 128 host genes that were responsive to MYRV1-Cp9B21 and MYRV2-CpC18 infection, respectively. Comparison of these virus-responsive genes revealed an overlap of 85 genes even though the overall degree of nucleotide sequence identity of the two reoviruses is less than 50%. Significantly, 84 of the 85 genes were altered in the same direction. Further comparison revealed that 51 % and 48% of the genes that were responsive to reoviruses MYRV1-Cp9B21 and MYRV2-CpC18 infection were also responsive to CHV1-EP713 infection. Finally, similar to results reported for hypovirus infection, a high percentage (59% and 66%) of the mycoreovirus responsive genes were also differentially expressed following disruption of the cellular G-protein signal transduction pathway. These data support the hypothesis that hypovirus and reovirus infections perturb common and specific C. parasitica regulatory pathways to cause hypovirulence and distinct sets of phenotypic changes. Keywords: Mycoreovirus, hypovirus, gene expression, microarray.
Project description:Infection of the chestnut blight fungus, Cryphonectria parasitica, by hypovirus CHV1-EP713 or by reoviruses MYRV1-Cp9B21 or MYRV2-CpC18 results in reduced fungal virulence (hypovirulence). However, additional phenotypic changes caused by the two groups of mycoviruses are quite different. CHV1-EP713 infection results in depressed pigmentation and conidiation while reovirus infection has little effect on these processes. We now report that loss of female fertility and resulting absence of virus transmission through sexual spores observed after hypovirus infection was not observed for reovirus infected C. parasitica. Reovirus-infected strains were male and female fertile and able to transmit virus to ascospore progeny at a high rate when serving as a female parent. Consistent with this result, real-time RT-PCR revealed that expression of two genes involved in sexual reproduction, the pheromone precursor gene, mf2-1 and yeast Ste12-like transcriptional factor gene, Cpst12, were less reduced in reovirus-infected strains than in hypovirus-infected strains. Analysis with a custom microarray cDNA chip containing EST clones representing ca 2,200 unique C. parasitica genes identified 140 and 128 host genes that were responsive to MYRV1-Cp9B21 and MYRV2-CpC18 infection, respectively. Comparison of these virus-responsive genes revealed an overlap of 85 genes even though the overall degree of nucleotide sequence identity of the two reoviruses is less than 50%. Significantly, 84 of the 85 genes were altered in the same direction. Further comparison revealed that 51 % and 48% of the genes that were responsive to reoviruses MYRV1-Cp9B21 and MYRV2-CpC18 infection were also responsive to CHV1-EP713 infection. Finally, similar to results reported for hypovirus infection, a high percentage (59% and 66%) of the mycoreovirus responsive genes were also differentially expressed following disruption of the cellular G-protein signal transduction pathway. These data support the hypothesis that hypovirus and reovirus infections perturb common and specific C. parasitica regulatory pathways to cause hypovirulence and distinct sets of phenotypic changes. Keywords: Mycoreovirus, hypovirus, gene expression, microarray.