RESEARCH GOAL
Dorith Rotenberg’s research program contributes fundamental knowledge towards developing alternative, effective and sustainable tools for diminishing vector-transmitted crop diseases. Current projects aim to: 1) identify and characterize molecular determinants of vector competence (i.e., the innate ability of a vector to transmit a pathogen to a primary host) to specifically disrupt the virus transmission cycle; 2) investigate the occurrence and ecology of recurring and emerging plant-pathogenic viruses that threaten crop production and food security; 3) collaborate with plant breeders to develop new sources of genetic resistance to viruses; 4) collaborate with molecular virologists to monitor dispersion and off-target effects of engineered vector-transmitted plant viruses carrying plant-enhancing traits; and 5) collaborate with insect geneticists to develop genome-editing tools that enable functional-interrogation of genes associated with virus transmission, while keeping an eye towards the possibility of genetic pest management for crop disease vectors.
PROJECTS
1. Tomato spotted wilt virus – Frankliniella occidentalis interactions
Orthotospovirus tomatomaculae (Order Bunyavirales, Family Tospoviridae, Genus Orthotospovirus; TSWV), formally the species Tomato spotted wilt orthotospovirus, is considered one of the top 10 most destructive plant viruses worldwide. TSWV is transmitted to field and greenhouse crops in a circulative-propagative manner by thrips vectors. Frankliniella occidentalis (the western flower thrips) – called a Super Vector by many researchers and growers alike – is the principal thrips vector species of TSWV.
From Rotenberg et al. 2015, doi.org/10.1016/j.coviro.2015.08.003
While we understand that thrips vector competence is defined by the ability to acquire, support replication, and disseminate TSWV along a dedicated route from the anterior region of the midgut to salivary glands for host inoculation to occur, very little is known about the role thrips molecules play in coordinating this transmission process. To that end, we dedicate our time to these initiatives:
- Transcriptomic- and proteomic-level investigations to characterize thrips molecular response to TSWV in tissues during early (midgut) and later (salivary gland) stages of the transmission process.
- Identification and characterization of thrips proteins that interact directly with the TSWV-encoded structural glycoprotein GN, the viral attachment protein that plays a role in virus entry.
- Identification of secreted thrips salivary gland proteins that stimulate or suppress plant defenses.
Image credit: Priya Rajarapu
2. Vector genome, transcriptome and proteome sequence resources
To enable functional genomics studies of thrips-TSWV interactions and to provide a missing taxon for contemporary insect genomics-based analyses, we needed a thrips genome!
Rotenberg coordinated an international consortium of 56 scientists from 17 research groups across 5 continents to annotate the first thysanopteran genome as part of a pilot i5k project at Baylor College of Medicine – Human Genome Sequencing Center (link here). The consortium generated an inbred line of Frankliniella occidentalis for sequencing and assembly, provided transcriptome sequences to support automated annotation of gene models, and manually curated and analyzed sequences of 100’s of genes to gain new genomic insights into the biology of thrips as a crop pest (Rotenberg et al., 2020).
GO here for NCBI FOCC genome sequence resources and here for AgDATA commons databases for the i5k genome and gene model sequences
AND here for NCBI RNAseq larval gut tissue transcriptomes (RNASeq)
ALSO here for FOCC salivary gland (Accn: MSV000089639) and saliva (Accn: MSV000089640) raw peptide data of the proteome
3. Vector dispersal and transmission dynamics of cereal viruses by hemipteran vectors
Members of the lab are investigating ecological and epidemiological factors that influence spatiotemporal dispersion and host selection of viruliferous vectors that colonize agronomic and weedy grass species. Vector and virus surveys are conducted in the field, and hypothesis-driven experiments are conducted in mesocosm-scale arenas under controlled environments.
The vector-virus systems include:
- Peregrinus maidis (corn planthopper) & maize mosaic rhabdovirus (MMV)
- Rhopalosiphum padi (bird cherry-oat aphid) & barley yellow dwarf viruses (BYDV-PAV and BYDV-PAS) (past system)
- Rhopalosiphum padi & maize dwarf mosaic virus (past system)
4.Traditional and biotech-based approached to control viral diseases caused by orthotospoviruses
My team and collaborators are making big steps in the following ways:
- Collaborating with a NCSU tomato breeder to identify new sources of Sw R genes that show promise against resistance-breaking (RB) TSWV in the greenhouse and field
- Co-developed promising transgenic tomato lines that target multiple genes of multiple orthotospovirus (TSWV, TCSV, RB-TSWV) for degradation; working now to move these transgenes into tomato breeding lines to enable breeding efforts of stacked traits
- Collaborating with a NCSU insect geneticist and genome-editing (GE) expert to develop GE thrips for functional analysis of novel thrips genes that may be associated with thrips vector competence, and to look ahead toward genetic management of thrips populations.