Jul 2026· Frontiers in Virology· 0 citations· 105 references
TL;DR
This review summarizes the current knowledge on taxonomy, genome organization, epidemiology, transmission biology, host range, and molecular interactions of ToLCNDV with host plants and vectors and discusses recent advances in genomics, transcriptomics, proteomics, gene editing, and molecular breeding.
Abstract
Tomato leaf curl New Delhi virus (ToLCNDV) is a highly adaptable begomovirus with an expansive and ever-increasing host range. Since its first report in the Indian subcontinent, the virus has rapidly spread across Asia, the Mediterranean Basin, North Africa, and other areas, largely due to efficient transmission by the whitefly
Bemisia tabaci
. The virus causes severe economic losses in tomato and cucurbit crops, with reported yield reductions ranging from 80% to 100% depending on crop stage, host genotype, and epidemic severity. ToLCNDV has a bipartite circular single-stranded DNA genome that encodes proteins involved in replication, movement, pathogenicity, and suppression of host defense responses. Rapid host range expansion, emergence of new strains, and breakdown of resistance have been facilitated by its high mutation rate, frequent recombination, genome reassortment, and interactions with associated DNA satellites. This review summarizes the current knowledge on taxonomy, genome organization, epidemiology, transmission biology, host range, and molecular interactions of ToLCNDV with host plants and vectors. Particular attention is given to natural sources of resistance in tomato and cucurbits, the genetic basis of resistance loci, host susceptibility factors, and viral counter-defense strategies. This review also discusses recent advances in genomics, transcriptomics, proteomics, gene editing, and molecular breeding as promising tools for durable disease management. Although progress has been made in resistance gene discovery and host–virus interaction studies, sustainable management remains challenging due to the rapid evolution of viruses and the adaptability of vectors. The future management of ToLCNDV will be based on a combination of resistant cultivars, clean plant material, correct diagnosis, whitefly control, real-time surveillance, and omics-guided breeding strategies. A systems-level understanding of the host–virus–vector relationship will be essential for developing resilient crop production systems under changing climatic and agricultural conditions.
Tomato leaf curl New Delhi virus (ToLCNDV) is a bipartite begomovirus with a broad host range and marked geographic variation in host adaptation. Whereas Asian isolates readily infect solanaceous crops, Mediterranean isolates are mainly adapted to cucurbits and infect tomato poorly. The molecular basis of this divergence remains unclear. Here, we compared Indian (ToLCNDV-IN) and Spanish (ToLCNDV-ES) isolates using reciprocal pseudo-recombinants to infect Solanum lycopersicum and Nicotiana benthamiana. Both DNA-A components replicated in tomato leaves, indicating that the inability of ToLCNDV-ES to infect tomato is not due to defective replication. Pseudo-recombinant analyses revealed that the DNA-B-IN component efficiently supported systemic infection of the heterologous DNA-A-ES, whereas the reciprocal combination established systemic infection only at low frequency. Furthermore, DNA-A from the IN isolate was unable, or only rarely able, to establish systemic infection in tomato in the absence of DNA-B, demonstrating a strict requirement for DNA-B-mediated movement functions. In N. benthamiana, all viral combinations systemically infected plants. Although both DNA-A components were capable of systemic infection without DNA-B in this host, viral accumulation was significantly reduced compared with bipartite infections, indicating that DNA-B enhances infection efficiency but is not essential for long-distance movement. Unexpectedly, a coat protein (CP)-mutated version of ToLCNDV-ES failed to establish systemic infection in N. benthamiana and Cucumis melo despite normal replication, revealing an essential role for CP in systemic movement. Collectively, our findings identify DNA-B as a major determinant of tomato infectivity and reveal an essential role for CP in systemic movement of the Mediterranean ToLCNDV isolate.
Tomato spotted wilt virus (TSWV) is an economically devastating pathogen that rapidly overcomes genetic resistance in major crops. Reverse genetic systems are crucial for investigating plant-virus interactions and resistance breaking mechanisms, and developing these tools for segmented ambisense RNA viruses remains a crucial challenge. Current TSWV-clones rely on extensively modified Asian isolates requiring co-delivery of multiple replication helpers and viral silencing suppressors. Streamlining these systems for regionally significant strains with minimal genetic alterations is essential. Here we developed the first infectious clone of a USA TSWV isolate (PA01). Three binary plasmids contain cDNAs for the antigenomic L and S segments, and the genomic M segment, with enhanced GFP replacing NSs on the S segment. Co-delivery of the cucumovirus 2b alone or in combination with tombusvirus P19 or begomovirus AL2, achieved a high proportion of systemically infected Nicotiana benthamiana and Capsicum annuum plants. In N. tabacum, co-delivering the Caenorhabditis elegans cell death suppressor CED-9, or using NahG transgenic plants produced 20 to 62% systemically infected plants. These data indicate that in addition to the anti-viral RNA silencing machinery, additional host defense pathways influence TSWV rescue and systemic infection from cDNA.
Haden Ball, O. Atallah, H. García-Ruíz et al.· Molecular Plant-Microbe Inte...· 0 citations
Whether, and where, genomic technologies have altered breeding outcomes rather than merely accelerating gene discovery is examined, and the available evidence indicates that genomic resources have substantially improved the resolution of resistance discovery and the precision of marker-assisted introgression, but have not yet demonstrably improved durability.
Vishal Singh, Mitali Tiwari, Diksha Kushwaha et al.· Uttar Pradesh Journal of Zoo...· 0 citations
The tomato Tm-22 gene is a highly effective, and durable resistance gene in agriculture that has protected tomato production against viruses of the Tobamovirus genus, such as tomato mosaic virus (ToMV) and tobacco mosaic virus (TMV) for over 60 years. This dominant R gene, originally sourced from wild tomato species (Solanum peruvianum), acts by recognizing the viral movement protein (MP) and triggering an immune response, often resulting in extreme resistance (ER). However, this durable protection is challenged by a recently emerged new tobamovirus named tomato brown rugose fruit virus (ToBRFV, Tobamovirus fructirugosum). ToBRFV-encoded MP is responsible for ER breakdown. Here, we present evidence that while ToBRFV can evade Tm-22-mediated ER, Nicotiana benthamiana and tomato plants carrying Tm-22 still remain partially resistant to ToBRFV. We show that ToBRFV MP is recognized by and interacts with Tm-22 to trigger an attenuated hypersensitive response. Moreover, we discover that overexpression of Tm-22 can enhance resistance to ToBRFV. These findings demonstrate the practical value of Tm-22 in ongoing resistance breeding programs and open a potential avenue to restore Tm-22 immunity through upregulation of Tm-22 expression.
Shaokang Zhang, M. Bernards, Aiming Wang· PLoS Pathogens· 0 citations
Background: Sequence analyses and phylogenetic comparison indicated that, the five isolates of B. coheni might have evolved by recombination between viruses related to two or more viral ancestors. The isolates were different from north Indian isolates, with variability even within isolates collected from a geographical location, indicating that, there will be continuous variability in geminiviruses.
Objective: To study the genetic diversity of ToLCD belongs to a group of closely related begomoviruses that emerged in the regions of Tamil Nadu, India, and to identify and determine their molecular variability.
Methods: Infected plant samples of ToLCV were collected from S. lycopersicum plants expressing typical symptoms of leaf curling, stunting, distortion, interveinal yellowing and necrosis of older leaves from tomato growing areas of Salem, Erode, Coimbatore, Madurai and Tirunelveli districts of Tamil Nadu. Totally 11 villages were surveyed randomly during 2010-2012 and the plant samples were immediately frozen in liquid nitrogen and stored at -80°C for further studies.
Results: The ToLCD symptoms varied from place to place and were exhibiting mild to severe leaf curling, reduction in leaf size and shortening of internode, upward curling, stunted growth, reduction in leaf size and puckering. The PCR was performed using ToLCV specific primers and fragment length of ~2.4 kb size obtained in 15 of 19 samples tested to confirm the presence of ToLCV. Based on the above work the ToLCV specific primers were designed and analyzed for further study. The complete nucleotide sequences (~2.7 kb) of selected isolates amplified by PCR were found to be monopartite genome and identified as 2 species of Tomato leaf curl viruses. On the basis of nucleotide similarity (89%) the virus from Tomato leaf curl Karnataka virus-CBE 1 and Tomato leaf curl Karnataka virus-SA1 of Tamil Nadu and virus from Tomato leaf curl Gujarat virus- EDE1, Tomato leaf curl Gujarat virus-TRN1 and Tomato leaf curl Gujarat virus-MDU1 have been identified ToLCKV and ToLCGV. The proposed name is ToLCKV and ToLCGV.
Conclusion: This study is a report that reveals the presence of new strains of geminiviruses infecting tomato plants, which have single genomic component and molecular diversity of Tamil Nadu region. Transcription of this single component produces all gene products required to support a complete cycle of infection and transmission of the virus.
M. Deivamani, S. Rageshwari, V. Satya et al.· Genetics and Molecular Resea...· 0 citations
Maize yellow mosaic virus (MaYMV) is an emerging polerovirus of corn and other grass species. Due to its broad host range and transmission by multiple aphid species, management strategies such as crop rotations, pesticides, and weed control are likely ineffective. Therefore, resistant cultivars are needed. In this study, we characterized the Goodman 282 maize diversity panel for its response to MaYMV. Leaf reddening symptoms were quantified, and diagnostics were performed to assess infection and obtain a semi-quantitative measure of virus titer. Low titer lines and inbreds representing symptomatic and asymptomatic infected phenotypic classes were characterized further by RT-qPCR. Genome-wide association studies were performed using MLM, FarmCPU, and BLINK models to identify SNPs associated with disease. In total, 64% of lines were asymptomatically infected. Although all lines tested positive for infection by MaYMV in at least one experiment, Ky226 had reduced viral titer compared to other lines. Sixteen quantitative trait nucleotides (QTN) were identified, many of which are linked to genes implicated in flavonoid, carotenoid, and phenolic metabolic pathways as well as antiviral defense. Notably, a QTN associated with a chalcone synthase, a key enzyme in the flavonoid biosynthesis pathway, was detected by even the most conservative, MLM model. These results indicate that the genetic architecture of corn in response to MaYMV is complex, and that developing immune cultivars may not be achievable using natural sources of genetic variation. However, this study provides a foundation for breeding maize with improved tolerance and advances our understanding of host response to MaYMV infection.
Erik W. Ohlson, Christopher A. Nacci, Nitika Khatri et al.· bioRxiv· 0 citations