Genetic analysis of the tomato russet mite provides evidence of oligophagy and a widespread pestiferous haplotype

Abstract

Worldwide, the tomato russet mite (TRM), Aculops lycopersici (Eriophyidae), is a key pest on grown tomatoes besides infesting other cultivated and wild Solanaceae; however, information on TRM basics aspects supporting effective control strategies still lacking, mainly regarding its taxonomic unit and genetic diversity and structure. As A. lycopersici is reported on different species and genera of host plants maybe, populations associated with different host plants constitute specialized cryptic species, such as showed for other eriophyids previously considered generalists. The main aims of this study were to i) con rm the TRM taxonomic unity of populations from different host plants and localities as well as the species oligophagy; ii) to advance the understanding on TRM host relationship and invasion history. For this purpose it was evaluated the genetic variability and structure of populations from different host plants along crucial areas of occurrence, including that potentially of origin and the invaded ones, based on DNA sequences of mitochondrial (Cytochrome c oxidase subunit I) and nuclear (Internal Transcribed spacer, D2 28S) genomic regions. Specimens from South America (Brazil) and Europe (France, Italy, Poland, The Netherlands) were collected from tomato and other solanaceous species from the Solanum and Physalis genera. Final TRM datasets were composed by 101, 82 and 50 sequences from the COI (672 bp), ITS (553 bp) and D2 (605 bp) regions, respectively. Distributions and frequencies of haplotypes (COI) and sequence variants (D2 and ITS1) were inferred; pairwise genetic distances, and phylogenetic analysis were performed, including Bayesian Inference (BI) combined analysis. Genetic divergences for mitochondrial and nuclear genomic regions from TRM associated with different host plants were even lower than those observed in other eriophyid taxa con rming co-speci c of TRM populations and oligophagy of this eriophyid mite. Four haplotypes (cH) were identi ed from the COI sequences being cH1 the most frequent, representing 90% of all sequences occurring in all host plants studied (Brazil, France, The Netherlands); the other haplotypes were present exclusively in Brazilian populations. Six variants (I) were identi ed from the ITS sequences: I-1 was the most frequent (76.5% of all sequences), spread in all countries and associated with all host plants, except for S. nigrum. Just one D2 sequence variant was found in all studied countries. The genetic homogeneity among populations highlights occurrence of a highly invasive and not host-speci c haplotype. These results also do not corroborate the hypothesis that differential symptomatology/damage intensity by tomato varieties and solanaceous host plants could be due to the genetic diversity of the associated mite populations. Even this contribution was not primarily aimed to trace TRM invasion routes, genetic evidence, jointly with the main host plant history, corroborate the hypothesis of a TRM South American origin. Host plant táxon LocalityGeographical coo...

Diptacus rubuscolum Trinidad, Duarte and Navia (Eriophyoidea: Diptilomiopidae) on blackberry (Rubus ulmifolius Schott) in Mexico: occurrence, complementary description, and biology

“…However, our results after analysing partial sequences of the D2 region confirmed a clear separation between D. rubuscolum and other Diptacus species, with genetic variations of 7-25%. Analyses of this region from other Eriophyidae species revealed variation of 2-19% amongst Abacarus species (Duarte et al 2019), 30-36% amongst Aculops species (Duarte et al 2023), 2% between Aceria tosichella Keifer and A. eximia Sukhareva (Skoracka et al 2012), and 4% between Eriocaenus ramosissimi Petanović & Amrine and E. equiseti Farkas (Petanović et al 2015). In all our surveys and despite sampling all plant structures and on six different occasions, we did not find Acalitus essigi or A. orthomera, which have been reported previously on blackberry, R. ulmifolius from Michoacán, Mexico (Ayala-Ortega et al 2019).…”

Molecular Methods for the Simultaneous Detection of Tomato Fruit Blotch Virus and Identification of Tomato Russet Mite, a New Potential Virus–Vector System Threatening Solanaceous Crops Worldwide

“…As well, ribosomal DNA has repeatedly provided insights into the genetic basis of evolution of recently diverged arthropod species and genera, and it is often a good candidate as a molecular taxonomic key for species discrimination [36,37]. For eriophyid species, both the ribosomal ITS and the D1-D12 domains of the 28S region have proven to be informative [20,[38][39][40]. In addition, in the case of candidate ETVs, a diagnostic pipeline using RT-PCR was developed and proved to be effective for the simultaneous identification of eriophyid at the species level and the detection of viruses [41]; in fact, by the incorporation of a reverse transcription step, not only single-copy genomic DNA but also multiple transcripts are targeted, increasing the total amount of template, thus decreasing the minimum number of individuals to be detected; in the meantime, it also allows the amplification of RNA viruses.…”

“…TRM is a vagrant eriophyoid mite and, differently from most eriophyoid species, is regarded as a pest in a variety of crops belonging to the Solanaceae family [19]. Presently, TRM can be found in both tropical and temperate parts of the globe with great economic impact, even though the most corroborated hypothesis may lead to a South American origin of TRM [20]. The availability of appropriate diagnostic tests for ToFBV detection is crucial given the growing number of reports and interest in the virus, particularly in light of the rising alert.…”

Redescription of Pronematus ubiquitus (McGregor, 1932) (Acari, Iolinidae), description of two new species and redescription of two additional species with a review of and key to all Pronematus species

“…However, DNA sequencing of more species, preferably with more than one marker gene is required to elucidate relationships. Studies have shown that when COI is combined with other marker genes such as 28r-RNA, clade structure can change (Duarte et al 2023). This underscores the importance of additional research, integrating barcoding with morphological identification as to make the species delimitation more reliable (Puillandre et al, 2012).…”