Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Biology and Microbiology

First Advisor

Shin-Yi Marzano


Soybean leaf-associated gemycircularvirus-1 (SlaGemV-1) is a novel mycovirus discovered through the metagenomic sequencing of soybean leaves which is capable of inducing hypovirulence in the highly pathogenic fungus Sclerotinia sclerotiorum. RNASeq analysis techniques were used to determine the transcriptional changes caused by the infection of virus in S. sclerotiorum, as well as the transcriptional changes in Glycine max caused by the colonization of hypovirulent, SlaGemV-1-infected S. sclerotiorum. RNASeq results indicate that viral infection leading to hypovirulence may attenuate expression of genes relating to cell wall synthesis, microtubule formation, and metabolism of steroids and natural antibiotics. Cytochrome P450-related genes, kinesin domain genes, and methyltransferase genes were found to be downregulated in the presence of SlaGemV-1 in S. sclerotiorum. These genes remain possible targets for further studies to determine the reasons for the phenotypic changes seen in the hypovirulence induced by SlaGemV-1 in S. sclerotiorum. Furthermore, transcriptional analysis shows changes in both the jasmonic acid-regulated pathway of induced systemic resistance (ISR) as well as the salicylic acid-regulated pathway of systemic acquired resistance (SAR) in plants colonized with the hypovirulent fungi. Upregulation of these defense pathways may indicate evidence of defense priming by the hypovirulent fungi to prevent further colonization of pathogenic fungi, and even other bacterial or viral infections.

Library of Congress Subject Headings

Sclerotinia sclerotiorum.
Pathogenic fungi.
Fungal viruses.
Plants -- Virus resistance.

Number of Pages



South Dakota State University



Rights Statement

In Copyright