Endogenized hypervirulence-associated DNA virus BdDV-1 is primarily restricted to enzootic lineages of the amphibian pathogen Batrachochytrium dendrobatidis. Endogenized hypervirulence-associated DNA virus BdDV-1 is primarily restricted to enzootic lineages of the amphibian pathogen Batrachochytrium dendrobatidis

The Global Panzootic Lineage (GPL) of the pathogenic fungus Batrachochytrium dendrobatidis (Bd) has caused severe amphibian population declines, yet the drivers underlying the high frequency of GPL in regions of amphibian decline are unclear. Using publicly available Bd genome sequences, we identified multiple non-GPL Bd isolates that contain a circular Rep-encoding single stranded DNA-like virus which we named BdDV-1. We further sequenced and constructed genome assemblies with long read sequences to find that the virus is integrated into the nuclear genome in some strains. Attempts to cure virus positive isolates were unsuccessful, however, phenotypic differences between naturally virus positive and virus negative Bd isolates suggested that BdDV-1 decreases the growth of its host in vitro but increases the virulence of its host in vivo. BdDV-1 is the first described CRESS DNA mycovirus associated with hypervirulence with a distribution inversely associated with the emergence of the panzootic lineage. Overall design: To identify differentially expressed genes (DEGs) between v+ and v- Bd-BRAZIL we extracted and sequenced mRNA from three samples of the virus positive strain, CLFT067 and the virus negative strain, CLFT071. These strains were selected due to their close phylogenetic relationship and their shared geographic location

致病性真菌蛙壶菌（Batrachochytrium dendrobatidis, Bd）的全球大流行谱系（Global Panzootic Lineage, GPL）已造成两栖动物种群严重衰退，但该谱系在两栖动物衰退区域高频出现的驱动机制仍不明确。本研究利用公开可得的Bd基因组序列，鉴定出多株非GPL型Bd分离株携带一种环状Rep编码单链DNA类病毒，并将其命名为BdDV-1。我们进一步通过长读长测序技术完成基因组组装，发现该病毒可整合至部分菌株的核基因组中。尽管尝试清除病毒阳性分离株均未成功，但天然病毒阳性与阴性Bd分离株间的表型差异表明：BdDV-1可在体外降低宿主的生长速率，却在体内增强宿主的毒力。BdDV-1是首个被报道的与超强毒力相关的环状单链DNA真菌病毒（CRESS DNA mycovirus），其分布与该大流行谱系的出现呈负相关。总体实验设计：为鉴定病毒阳性（v+）与病毒阴性（v-）Bd-BRAZIL菌株间的差异表达基因（differentially expressed genes, DEGs），本研究从病毒阳性菌株CLFT067与病毒阴性菌株CLFT071的三份样本中提取信使RNA（mRNA）并进行测序。选取这两株菌株的原因在于二者亲缘关系紧密且地理来源一致。