Seed transmission is an important factor in the epidemiology of plant pathogens. Geminiviruses are serious pests spread in tropical and subtropical regions. They are transmitted by hemipteran insects, but a few cases of transmission through seeds were recently reported. Here, we investigated the tomato seed transmissibility of the begomovirus tomato yellow leaf curl Sardinia virus (TYLCSV), one of the agents inducing the tomato yellow leaf curl disease, heavily affecting tomato crops in the Mediterranean area. None of the 180 seedlings originating from TYLCSV-infected plants showed any phenotypic alteration typical of virus infection. Moreover, whole viral genomic molecules could not be detected in their cotyledons and true leaves, neither by membrane hybridization nor by rolling-circle amplification followed by PCR, indicating that TYLCSV is not a seed-transmissible pathogen for tomato. Examining the localization of TYLCSV DNA in progenitor plants, we detected the virus genome by PCR in all vegetative and reproductive tissues, but viral genomic and replicative forms were found only in leaves, flowers and fruit flesh, not in seeds and embryos. Closer investigations allowed us to discover for the first time that these embryos were superficially contaminated by TYLCSV DNA but whole genomic molecules were not detectable. Therefore, the inability of TYLCSV genomic molecules to colonize tomato embryos during infection justifies the lack of seed transmissibility observed in this host.

Two species of palm tree pests, Oryctes elegans and Oryctes agamemnon (Coleoptera: Scarabaeidae), cause significant damage to date palm trees (Phoenix dactylifera) in many countries in the Middle East. Despite several decades of research and the implementation of numerous control strategies, including mechanical, chemical, regulatory, and biosecurity measures, managing these pests remains challenging. Control of O. rhinoceros in the Pacific using an entomopathogenic virus is a landmark of classical biological control. In this study, we used a transcriptomic approach to examine the virome of populations of two Oryctes species across various regions in southern Iran, with the hope of discovering natural viral pathogens as potential biocontrol agents. Total RNA was extracted from a pool of larval gut samples and sequenced using the Illumina NovaSeq 6000. After analysing the RNA-Seq data, 28 novel virus sequences, including a diverse range of RNA and DNA viruses, were identified. Phylogenetic analyses revealed that these newly discovered viruses are evolutionarily linked with other closely related members in several families, including Partitiviridae, Picobirnaviridae, Totiviridae, Dicistroviridae, Tombusviridae, Nodaviridae, Potyviridae, Endornaviridae, Circoviridae and some unassigned viruses such as Negevirus and Jivivirus. Given the similarity of some of these viruses to plant viruses, and viruses reported from fungi and protists and their unclear host association, we have tentatively named them "Oryctes-associated viruses." This study uncovers the great diversity of viruses in Oryctes species; however, further studies are necessary to determine their natural incidence, geographical distribution, impact on their hosts, and their potential as biological control agents for these significant date palm pests.