Novel partiti-like viruses are conditional mutualistic symbionts in their normal lepidopteran host, African armyworm, but parasitic in a novel host, Fall armyworm

• DOI: 10.1371/journal.ppat.1008467
• Publication Date: 2020-06-22T17:42:59Z
• Authors: Pengjun Xu; Liyu Yang; Xianming Yang; Tong Li; Robert I. Graham; Kongming Wu; Kenneth Wilson
• Keywords: Fall armyworm

Recent advances in next generation sequencing (NGS) (e.g. metagenomic and transcriptomic sequencing) have facilitated the discovery of a large number new insect viruses, but characterization these viruses is still its infancy. Here, we report discovery, using RNA-seq, three partiti-like from African armyworm, Spodoptera exempta (Lepidoptera: Noctuidae), which are all vertically-transmitted transovarially mother to offspring with high efficiency. Experimental studies show that reduce their host's growth rate reproduction, enhance resistance nucleopolyhedrovirus (NPV). Via microinjection, were transinfected into novel host, newly-invasive crop pest sub-Saharan Africa (SSA), Fall S. frugiperda. This revealed this appear be deleterious without any detectable benefit; reducing reproductive increasing susceptibility NPV. Thus, conditional mutualistic symbionts normal exempta, parasitic Transcriptome analysis frugiperda infected, or not, indicates may regulate pathways related immunity reproduction. These findings suggest possible management strategy via artificial host-shift discovered by NGS.