Biology subjects

Ravnikar, M.

Publications and source records attributed to Ravnikar, M..

4 recordsLinked to original sources

bioRxiv2023

Virome analysis of irrigation water sources provides extensive insights into the diversity and distribution of plant viruses in agroecosystems

Plant viruses pose a significant threat to agriculture. Several are stable outside their hosts, can enter water bodies and remain infective for prolonged periods of time. Even though the quality of irrigation water is of increasing importance in the context of plant health, the presence of plant viruses in irrigation waters is understudied. In this study, we conducted a large-scale high-throughput sequencing (HTS)-based virome analysis of irrigation and groundwater sources to obtain complete information about the abundance and diversity of plant viruses in such waters. We detected nucleic acids of plant viruses from 20 families, discovered several novel plant viruses from economically important taxa, like Tobamovirus and observed the influence of the water source on the present virome. By comparing viromes of water and surrounding plants, we observed presence of plant viruses in both compartments, especially in cases of large-scale outbreaks, such as that of tomato mosaic virus. Moreover, we demonstrated that water virome data can extensively inform us about the distribution and diversity of plant viruses for which only limited information is available from plants. Overall, the results of the study provided extensive insights into the virome of irrigation waters from the perspective of plant health. It also suggested that an HTS-based water virome surveillance system could be used to detect potential plant disease outbreaks and to survey the distribution and diversity of plant viruses in the ecosystems.

molecular biology↗

bioRxiv2022

Diversity and pathobiology of an ilarvirus unexpectedly detected in diverse host plants and in global sequencing data

High-throughput sequencing (HTS) and sequence mining tools revolutionized virus detection and discovery in recent years and implementing them with classical plant virology techniques results to a powerful approach to characterize viruses. An example of a virus discovered through HTS is Solanum nigrum ilarvirus 1 (SnIV1) (family Bromoviridae), which was recently reported in various solanaceous plants from France, Slovenia, Greece, and South Africa. It was likewise detected in grapevines (Vitaceae) and several Fabaceae and Rosaceae plant species. Such a very diverse host association is atypical for ilarviruses, thus warranted further investigation. In this study, modern and classical virological tools were combined to accelerate the characterization of SnIV1. Through HTS-based virome surveys, mining of sequence read archive datasets, and literature search, SnIV1 was further identified from diverse plant and non-plant sources globally. SnIV1 isolates showed relatively low variability compared to other phylogenetically related ilarviruses. Phylogenetic analyses showed a distinct basal clade of isolates from Europe, while the rest formed clades of mixed geographic origin. Furthermore, systemic infection of SnIV1 in Solanum villosum and its mechanical and graft transmissibility to solanaceous species were demonstrated. Near identical SnIV1 genomes from the inoculum (S. villosum) and inoculated Nicotiana benthamiana were sequenced, thus partially fulfilling Kochs postulates. SnIV1 was shown to be seed-transmitted and potentially pollen-borne, has spherical virions, and possibly induces histopathological changes in infected N. benthamiana leaf tissues. Overall, this study provided information to better understand the diversity, distribution, and pathobiology of SnIV1, but whether it could emerge as a destructive pathogen remains uncertain. FundingO_LIEU Horizon 2020 Marie Skodowska-Curie Actions Innovative Training Network (H2020 MSCA-ITN) project no. GA 813542 C_LIO_LIAdministration of the Republic of Slovenia for Food Safety, Veterinary Sector and Plant Protection and Slovenian Research Agency (ARRS) funding no. P4-0165, P4-0407, J4-4553 C_LIO_LIBalik Scientist Program (Republic Act 11035) of the Department of Science and Technology- Philippine Council for Agriculture, Aquatic, and Natural Resources Research and Development (DOST-PCAARRD), Republic of the Philippines C_LIO_LIThe Belgian FPS Health Food Chain Safety and Environment under Project RT18/3 SEVIPLANT C_LI

microbiology↗

bioRxiv2022

In-depth study of tomato and weed viromes reveals undiscovered plant virus diversity in an agroecosystem

BackgroundIn agroecosystems, viruses are well known to influence crop health and a few cause phytosanitary and economic problems, but their diversity in non-crop plants and role outside the disease perspective is less known. An extensive virome exploration that includes both crop and diverse weed plants is therefore needed to better understand roles of viruses in agroecosystems. Such unbiased exploration is possible through viromics, which could generate biological and ecological insights from immense high-throughput sequencing (HTS) data. ResultsHere, we implemented HTS-based viromics to explore viral diversity in tomatoes and weeds in farming areas at a nation-wide scale. We detected 125 viruses, including 79 novel species, wherein 65 were found exclusively in weeds. This spanned 21 higher-level plant virus taxa dominated by Potyviridae, Rhabdoviridae, and Tombusviridae, and four non-plant virus families. We detected viruses of non-plant hosts and viroid-like sequences, and demonstrated infectivity of a novel tobamovirus in plants of Solanaceae family. Diversities of predominant tomato viruses were variable, in some cases, comparable to that of global isolates of same species. We phylogenetically classified novel viruses, and showed links between a subgroup of phylogenetically-related rhabdoviruses to their taxonomically-related host plants. Ten classified viruses detected in tomatoes were also detected in weeds, which might indicate possible role of weeds as their reservoirs, and that these viruses could be exchanged between the two compartments. ConclusionsWe showed that even in relatively well studied agroecosystems, such as tomato farms, a large part of very diverse plant viromes can still be unknown and is mostly present in understudied non-crop plants. The overlapping presence of viruses in tomatoes and weeds implicate possible presence of virus reservoir and possible exchange between the weed and crop compartments, which may influence weed management decisions. The observed variability and widespread presence of predominant tomato viruses and the infectivity of a novel tobamovirus in solanaceous plants, provided foundation for further investigation of virus disease dynamics and their effect on tomato health. The extensive insights we generated from such in-depth agroecosystem virome exploration will be valuable in anticipating possible emergences of plant virus diseases, and would serve as baseline for further post-discovery characterization studies.

ecology↗

bioRxiv2020

Spider webs as eDNA tool for biodiversity assessment of life's domains

The concept of environmental DNA (eDNA) utilizes nucleic acids of organisms directly from the environment. Recent breakthrough studies have successfully detected a wide spectrum of prokaryotic and eukaryotic eDNA from a variety of environments, ranging from ancient to modern, and from terrestrial to aquatic. These numerous sources promise to establish eDNA as a tool for diverse scientific settings. Here, we propose and establish spider webs as a source of eDNA with far reaching implications. First, we conducted a field study to track specific arthropod targets from different spider webs. We then employed high-throughput amplicon sequencing of taxonomic barcodes to investigate the utility of spider web eDNA for biodiversity monitoring of animals, fungi and bacteria. Our results show that genetic remains on spider webs allow the detection of even the smallest target organisms. We also demonstrate that eDNA from spider webs is useful in research of community compositions in different domains of life, with potentially highly detailed temporal and spatial information.

ecology↗