DNA plant viruses: biochemistry, replication, and molecular genetics

Co-Occurrence of Viruses, Plant Pathogens, and Symbionts in an Underexplored Hemipteran Clade

“…For most geminiviruses, it is not clear if they are propagative in the host. We also did not detect Caulimoviridae, which are dsDNA reverse transcribing viruses mostly transmitted by a range of hemipterans ( Shafiq et al., 2020 ), although it is unclear how many of these viruses are circulating and propagative in the insects, suggesting perhaps these plant viruses could be vectored by these treehoppers but not easily detected by these methods.…”

“…We did not find any geminiviruses, including those related to Topocurvirus which includes the Micrutalis -vectored pseudo-curly top virus, TPCTV, or Grablovirus which includes the Spissistilus -vectored Grapevine red blotch-associated, GRBaV. Although most Geminiviridae are persistent or semipersistent and circulative in their hosts ( Shafiq et al., 2020 ), therefore potentially found in the hemolymph or tissue surrounding the bacteriomes in this study, these are ssDNA viruses that form a dsDNA intermediate in the plant host but may not form a dsDNA phage in the insect, unless they are propagative. For most geminiviruses, it is not clear if they are propagative in the host.…”

“…Whereas most viruses of plants have single-stranded RNA genomes and therefore would not be detected in this DNA sequence-based study, we searched for a wide range of DNA plant viruses, expecting to potentially discover some of these, especially those vectored by hemipterans including treehoppers ( Mead, 1986 ; Briddon et al., 1996 ; Bahder et al., 2016 ; Varsani et al., 2017 ; Shafiq et al., 2020 ). We did not find any geminiviruses, including those related to Topocurvirus which includes the Micrutalis -vectored pseudo-curly top virus, TPCTV, or Grablovirus which includes the Spissistilus -vectored Grapevine red blotch-associated, GRBaV.…”

“…Many insects that host microbial symbionts can also vector significant plant pathogens ( Hogenhout et al., 2008a ; Hogenhout et al., 2008b ; Scholthof et al., 2011 ; Mansfield et al., 2012 ; Weintraub et al., 2019 ; Shafiq et al., 2020 ), but investigating the co-occurrence and forces underlying insect symbiont and plant pathogen infection presents a challenge. Some data suggest there could be an energetic cost of hosting symbionts, which might reduce an insect’s plant pathogen vectoring ability, while conversely, the benefits of symbionts might provide energy or metabolic advantages that increase plant pathogen transmission ( Heck, 2018 ; Gonella et al., 2019 ).…”

“…The current study sought to characterize symbionts and potential plant pathogens in membracids, including neotropical species, examining co-occurrence and correlations in abundance as an initial survey of this underexamined group. Our approach used shotgun metagenomics of the membracid bacteriome and surrounding tissues and hemolymph, searched for matches to major bacterial plant pathogens ( Mansfield et al., 2012 ) including phytoplasmas ( Hogenhout et al., 2008b ), and DNA plant viruses ( Shafiq et al., 2020 ), and an array of bacteriophage ( Duron, 2014 ; Rouïl et al., 2020 ). Results showed our set of membracids hosted at least nine types of potential plant pathogens, in addition to 12 primary and secondary endosymbionts, along with numerous bacteriophages, and other viruses and parasites.…”