The endornaviruses are large dsRNA viruses that were described in the 1990s from plants (Valverde et al. 1990a, b; Wakarchuk and Hamilton 1990) and later reported in fungi and oomycetes (Fukuhara et al. 2006; Gilbert et al. 2019), while a large dsRNA from Vicia faba reported in the 1980s (Grill and Garger 1981) was later shown to be an endornavirus. They are unique and persistent with synergetic characters, which infect varied eukaryotes like plants, fungi, and oomycetes (Kozlakidis et al. 2013). Later, the endornaviruses have been awarded family status as Endornaviridae by the ICTV ( http://www.ictvonline.org/virusTaxonomy.asp?version=2009 ). They have a number of unique properties, including no evidence of encapsidation or even viral particles, a single very long ORF with a nick in the plus strand and the presence of a poly-C 39 end in some, but not all members of the group (Fukuhara et al. 2006).