Biology subjects

Lozano-Duran, R.

Publications and source records attributed to Lozano-Duran, R..

At least 19 recordsLinked to original sources

bioRxiv2026

NO VEIN is an ancestral immunity protein involved in plant-virus interaction

The conservation of immune systems from prokaryotes to eukaryotes can guide discovery of immunity genes across the tree of life. Most studies to date have focused on metazoan systems, while the extent of ancestral immunity conservation in plants remains underexplored. Here we show that NO VEIN (NOV), a plant protein previously characterized for its essential developmental roles in Arabidopsis thaliana, shares domain composition and structural similarity with Tiamat, a bacterial antiphage protein. In light of the antiviral function of the bacterial protein, we asked whether NOV is involved in plant-virus interactions. We found that NOV knockdown in the model plant Nicotiana benthamiana resulted in an impaired transcriptional response to tobacco rattle virus, including reduced induction of defense genes, and observed increased potato virus x accumulation in a secondary infection. We also reveal that NOV, previously considered plant-specific, has homologs in animals - pointing to a shared origin. Together, these findings uncover a deeply conserved protein involved in plant-virus interaction, and demonstrate the power of prokaryote-eukaryote homology to reveal new aspects of plant biology.

plant biology↗

bioRxiv2026

Nucleoporin 50a interacts with geminivirus C4 proteins and contributes to infection

Geminiviruses are plant DNA viruses that replicate in the nucleus of the host cell and rely on the host nucleocytoplasmic transport machinery to complete their infection cycle. While various geminiviral proteins have been reported to interact with plant transport factors, the contribution of nuclear pore complex components to geminivirus infection remains largely unexplored. Here, we identify nucleoporin 50a (NUP50a) as a previously unreported host factor that contributes to bhendi yellow vein mosaic virus (BYVMV) infection. Affinity purification coupled with mass spectrometry isolated NUP50a as a potential interactor of the BYVMV pathogenicity determinant C4, which was further validated by pull-down and co-immunoprecipitation assays. Yeast two-hybrid assays, bimolecular fluorescence complementation, and colocalization analysis demonstrated that BYVMV C4 directly associates with NUP50a predominantly in the nucleus. Virus-induced gene silencing of NbNUP50a significantly delayed symptom development and reduced viral DNA accumulation, suggesting that NUP50a is required for efficient BYVMV infection. Silencing NbNUP50a did not influence the subcellular localization of BYVMV C4, indicating that the role of NUP50a extends beyond determining C4 steady-state localization. Notably, NUP50a was found to associate with C4 proteins from three additional geminiviruses, supporting the possibility that targeting NUP50a represents a characteristic strategy among geminiviruses. Together, our findings provide evidence of a nuclear pore complex member involved in geminivirus pathogenesis. These results establish a framework for further study of the potential transport-dependent and/or transport-independent functions of NUP50a during viral infection.

plant biology↗

bioRxiv2026

Selective repurposing of the eukaryotic DNA replication machinery by a plant virus

Eukaryotic DNA viruses that replicate in the nucleus often exploit components of the host DNA replication machinery for genome replication. Geminiviruses, causal agents of devastating crop diseases worldwide, strictly depend on host factors to replicate their circular single-stranded (ss) DNA genomes, with only a single virus-encoded protein, Rep, required for this process. Rep recruits host replication proteins to the viral genome and catalyzes nicking and ligation at the initiation and termination sites of rolling-circle replication. Despite the reliance of geminiviral replication on plant proteins, the composition of the viral replisome remains largely unknown. Here, we use TurboID-based proximity labeling to identify plant proteins in the vicinity of the Rep proteins from the geminiviruses tomato yellow leaf curl virus (TYLCV) and abutilon mosaic virus (AbMV) during infection. Combining virus-induced gene silencing, infection assays, and chromatin immunoprecipitation, we identify host DNA replication-related factors required for viral genome replication and likely components of the viral replisome. Our results indicate that geminiviruses and related eukaryotic ssDNA viruses selectively repurpose components of the eukaryotic replication fork to support rolling-circle replication, and suggest that they follow a leading-strand replication mode while utilizing the lagging-strand DNA polymerase {delta}. These findings shed light on the molecular mechanism of geminiviral DNA replication and identify potential targets for engineering antiviral resistance in crops.

plant biology↗

bioRxiv2026

Extracellular vesicles associate with infectious geminiviral particles in the apoplast of infected plants.

Plant viruses have evolved diverse strategies to facilitate their movement and survival within the host. Among them, geminiviruses co-opt host cellular machinery to replicate and disseminate. Traditionally, viral propagation has been associated with intercellular symplastic trafficking mediated by plasmodesmata and viral movement proteins. However, recent evidence demonstrated that the plant RNA virus turnip mosaic virus (TuMV) components are associated with extracellular vesicles (EVs). EVs are membrane-bound structures secreted to the extracellular space to potentially mediate several plant-pathogen interactions such as cross-kingdom RNA interference or the delivery of stress response proteins. In animals, EVs facilitate viral transmission both within the host and across species, but knowledge about their potential roles in plant viral infection is scarce. In this study, we demonstrate that EVs isolated from geminivirus-infected plants contain complete viral genomes and both capsid and viral movement proteins. Furthermore, these EV fractions were demonstrated to be infectious when mechanically inoculated onto naive plants. This discovery suggests that EVs may serve as alternative carriers for geminivirus components, enabling long-range transport or potentially modulating host immune responses, and highlights geminiviral capacity to transverse membrane boundaries, essential for circulative arbovirus propagation in their insect vectors. Significance StatementViruses are obligate intracellular parasites that shape ecological communities and crucially challenge animal and plant health worldwide. Conversely to animal viruses, plant-infecting viruses rely on plasmodesmata to disseminate through their host and establish systemic infection. Nonetheless, most plant viruses are insect-transmitted whose ecological cycle relies on their insect vector spread. Thus, strategies to cross continuous membrane barriers are essential for their dissemination and may be potentially conserved in plant hosts. Our discovery that infectious viral entities are associated with EVs reveals an alternative pathway for geminiviral movement within plant hosts that could facilitate vector transmission, challenging our long-standing understanding of plant virus biology and expanding the current conception of plant viral pathology.

plant biology↗

bioRxiv2026

Karrikin and strigolactone signalling affect pattern-triggered immunity and resistance to specific pathogens

Hormone signalling is important for plant adaptation to biotic stress. Karrikins (KARs), smoke-derived compounds, and strigolactones (SLs), endogenous plant hormones, are families of butenolide mole-cules, sharing a convergent perception and signalling pathway to regulate a plethora of developmental processes and plant-symbiont relationships. Perception of KARs and SLs is mediated by the /{beta}-hydro-lase KARRIKIN INSENSITIVE 2 (KAI2) and DWARF14 (D14), respectively, each resulting in the for-mation of an E3 ubiquitin ligase complex with the F-Box protein MORE AXILLIARY GROWTH 2 (MAX2) to target transcriptional repressors of the SUPPRESSOR OF MAX2 (SMAX)/SMAX-LIKE (SMXL) family for degradation. Most likely, KAI2 additionally perceives a still elusive endogenous ligand (KAI2-ligand, KL). Recent reports suggest a role of KL/SL signalling in plant immunity, but how these pathways are involved in defence, while balancing appropriate symbiont interactions remains largely unknown. Here, we report that KL and SL signalling quantitatively modulate plant immune responses and pathogen re-sistance. In Arabidopsis thaliana (hereafter Arabidopsis), disrupting or de-repressing KL or SL signalling affects plant susceptibility to a variety of plant pathogens. Furthermore, we describe a previously un-known role for KL and SL signalling in modulating pattern-triggered immunity (PTI). Interfering with KL and SL perception in Arabidopsis had similar effects on microbe-associated molecular pattern (MAMP)-triggered reactive oxygen species production, but transcriptomic profiling suggests a predominant role for KL signalling in regulating the extent of PTI. Importantly, KAI2- and D14-mediated regulation of MAMP-triggered ROS production extends to Lotus japonicus and, in the case of KAI2, to Nicotiana benthamiana, indicating conserved immuno-modulatory roles across dicotyledonous lineages. Together our data identify KL and SL signalling, with a predominant role for the KL pathway, as a conserved modulatory layer of plant immunity and provides a framework for understanding how developmental pathways intersect with immune regulation.

plant biology↗

bioRxiv2026

An ancient cis-element regulates translation of arginine decarboxylase to control downstream polyamine biosynthesis and stress responses

Polyamines (PAs) are ubiquitous metabolites that, despite their simple structure, profoundly influence plant growth, development, and stress adaptation. Their cellular levels are largely determined by arginine decarboxylase (ADC), a key rate-limiting enzyme in their biosynthesis. We previously identified a [~]50 bp GC-rich sequence in the 5' untranslated region (UTR) of plant ADC genes, termed the ADC-box, that is conserved across land plants. Transient reporter assays in tomato, in which ADC upstream regions were decoupled from their native coding sequences and fused to reporter genes, suggested that this element represses translation. However, its function in the native genomic context and its impact on PA homeostasis remain unclear. Here, we combined CRISPR-Cas9 genome editing, metabolite profiling, enzymatic assays, and RNA structure probing to define ADC-box function in tomato and in the seedless land plant Marchantia polymorpha, which retains a conserved [~]20 bp core region. Mutation of the M. polymorpha ADC-box increased ADC activity and altered PA levels, indicating that the ADC-box functions as a conserved translational repressor. In tomato, disruption of the ADC-boxes in SlADC1 and SlADC2 increased ADC activity, demonstrating that the ADC-box acts as a translational repressor in its native context. These ehects were most pronounced under cold stress, when ADC transcript levels increase, suggesting that the ADC-box buhers stress-induced translation. Metabolically, ADC-box disruption led to agmatine accumulation and alterations in upstream intermediates, while downstream PA pools remained largely unchanged. SHAPE analysis revealed that the tomato ADC-box folds into a three-stem RNA structure, with a central stem representing the major inhibitory module. ADC-box mutants displayed altered plant-microbe interactions, with enhanced resistance to Pseudomonas syringae and Tobacco rattle virus, but increased susceptibility to Ralstonia solanacearum and Tomato yellow leaf curl virus. Together, these findings establish the ADC-box as an evolutionarily conserved cis-regulatory element that stabilizes PA homeostasis and modulates plant-microbe interactions.

plant biology↗

bioRxiv2026

Alternative splicing expands the functional portfolio of a plant virus to control the viral cycle

Viruses frequently have limited coding space, yet efficiently manipulate complex hosts by deploying intricate, often poorly understood strategies. Geminiviruses, devastating plant pathogens with small single-stranded (ss) DNA genomes, replicate in the nucleus aided by the viral replication-associated protein (Rep), the most conserved protein within this family and related ssDNA viruses. Rep initiates viral DNA replication and represses its own promoter to regulate the infection cycle. The molecular mechanisms enabling this dual functionality are so far unknown. Here, we show that the geminivirus tomato yellow leaf curl virus (TYLCV) exploits the host spliceosome to produce novel Rep splice variants. Splicing generates Rep isoforms lacking the central oligomerization domain that cannot initiate replication but strongly repress the Rep promoter. Conversely, Rep mutants deficient in splicing promote replication but fail to repress transcription. Reduced Rep splicing interferes with the viral gene expression hierarchy and decreases infectivity. Our findings therefore reveal a previously unrecognized viral strategy in which alternative splicing produces functionally specialized viral protein isoforms, providing a mechanistic explanation for the dual role of Rep in viral replication and gene regulation. Splicing events with potentially similar functional consequences in related viruses suggest that this strategy may have convergently evolved across diverse viral lineages infecting different domains of life.

plant biology↗

bioRxiv2026

Characterization of the C4 proteins encoded by okra-infecting geminiviruses in India

Okra (bhendi) is a widely cultivated food crop in warm regions of the world, with India contributing approximately 60% of global production. However, okra cultivation in India is severely constrained by viral diseases, among which infections caused by the geminiviruses bhendi yellow vein mosaic virus (BYVMV) and okra enation leaf curl virus (OELCuV), in association with their satellites, represent major limitations to crop productivity. In recent years, the geminivirus-encoded C4 protein has emerged as a key pathogenicity determinant in this viral family, with functions that include suppression of multiple layers of plant antiviral defence and induction of disease symptoms. Here, we comparatively characterize the C4 proteins of BYVMV and OELCuV by determining their targeting signals and subcellular localization, and by assessing their ability to induce developmental abnormalities and suppress the cell-to-cell spread of RNA silencing. Our results reveal that the two C4 proteins display distinct subcellular localization patterns, yet both are capable of inducing developmental alterations, likely through different mechanisms, and of suppressing the intercellular spread of RNA silencing, possibly via interaction with a common host factor. Together, these findings suggest that C4 might be a critical virulence factor in okra-infecting geminiviruses and act as a symptom determinant. The C4 proteins encoded by BYVMV and OELCuV therefore emerge as promising targets for the development of antiviral management strategies in okra.

plant biology↗

bioRxiv2025

Pervasive splicing in a plant DNA virus

RNA splicing is considered an oddity in plant viruses; here, unexpectedly, we find it to be prevalent in the geminivirus tomato yellow leaf curl virus. Transcriptome analysis revealed eight splicing events generating novel protein isoforms, six of which were validated and two shown to depend on the plant spliceosome. Splicing impairment reduced viral accumulation and symptom severity, demonstrating that splicing contributes to infectivity, potentially by expanding the viral proteome, and suggesting that plant virus transcriptomes need to be reassessed.

plant biology↗

bioRxiv2025

Proteome profiling of plant Cajal bodies uncovers kingdom-specific components

Insight into the molecular composition of cellular microenvironments is essential for understanding their function. Membraneless organelles (MLO), such as the nuclear Cajal body (CB), play fundamental roles in eukaryotic cells, but their very nature poses a challenge to biochemical isolation. Despite the relevance of the CB for cell function in plants and animals, its proteome remains to be profiled. Here, we purify plant CBs using a combination of biochemical isolation and fluorescence-activated particle sorting (FAPS) and define their proteome by mass spectrometry. Our work identifies 15 and 95 proteins uniquely localized and enriched in CBs, respectively, of which 22 are also labelled by CB markers in proximity labelling assays. CB proteins are preferentially involved in RNA processing, chromatin organization, and gene expression. While a partial overlap with known animal CB proteins exists, our data reveal a distinct, kingdom-specific CB proteome. These results provide the first comprehensive proteome of CBs and establishes a foundation for dissecting the molecular functions of this organelle across multicellular lineages.

plant biology↗

bioRxiv2025

Defender or accomplice? Dual roles of plant vesicle trafficking in restricting and enabling geminiviral systemic infection.

The vesicle trafficking system enables multidirectional cargo fluxes between endomembrane compartments, ensuring the viability of eukaryotic cells. However, vesicle trafficking plays dual roles during pathogen infections. In plants, the endomembrane system mediates autophagic immune responses but can also be hijacked by pathogens to facilitate successful infections. In this study, we demonstrate that vesicle trafficking machinery acts as a double-edged sword during infection by the geminivirus tomato yellow leaf curl Sardinia virus (TYLCSaV) in Nicotiana benthamiana. Virus-induced gene silencing (VIGS) of eight genes encoding key vesicle trafficking regulators revealed contrasting outcomes. Silencing of NbSAR1 and NbAP-1{gamma} significantly increased systemic geminiviral DNA accumulation, whereas silencing of Nb{delta}-COP, NbARF1, and clathrin genes almost completely abolished infection. Notably, this inhibition is hypothesized to result from direct or indirect impairment in viral movement, as replication remained unaffected by gene silencing. Furthermore, the observed effects affect other geminiviruses, including tomato yellow leaf curl virus (TYLCV) and beet curly top virus (BCTV), but not unrelated pathogens such as the RNA potato virus X (PVX) or the plant pathogenic bacterium Pseudomonas syringae. These findings suggest that while the vacuolar and autophagy branches of the vesicle trafficking system might mediate antiviral autophagic defense responses, the integrity of endocytosis and retrograde transport is essential for systemic geminiviral infection.

plant biology↗

bioRxiv2025

FaRIF at the Core of Strawberry Fruit Ripening: Deciphering its Targets and Interaction Networks

Ripening Inducing Factor (RIF) is a key NAC transcription factor regulating strawberry fruit ripening. Previous studies using RIF-RNAi and overexpression lines in Fragaria x ananassa and CRISPR knock-out lines in F. vesca have established the role of RIF in controlling ABA biosynthesis and signaling, cell wall remodeling, and secondary metabolism. In this study, we deciphered FaRIFs transcriptional regulatory network by combining ChIP-seq-based identification of its direct targets with an analysis of FaRIF-RNAi transcriptome data. These analyses revealed FaRIFs direct role in multiple aspects of strawberry fruit ripening, including the regulation of ripening-related transcription factors, phytohormone content and signaling, primary and secondary metabolism, and cell wall degradation. Additionally, using the TurboID-based proximity labeling approach, we have identified FaRIF interactors, including proteins involved in mRNA and protein homeostasis, as well as several NAC transcription factors. Among these, FaNAC034 was found to synergistically enhance FaRIFs transcriptional activity. This integrative analysis, combining transcriptome analysis, in vivo ChIP-seq, and proximity labeling, broadens our knowledge of FaRIF-mediated transcriptional networks and interaction partners, providing valuable insights into the molecular mechanisms underlying strawberry fruit ripening regulation by this transcription factor.

plant biology↗

bioRxiv2024

CuBe: a geminivirus-based copper-regulated expression system suitable for post-harvest activation.

The growing demand for sustainable platforms for biomolecule manufacturing has fueled the development of plant-based production systems. Agroinfiltration, the current industry standard, offers several advantages but faces limitations for large-scale production due to high operational costs and batch-to-batch variability. Alternatively, here, we describe the CuBe system, a novel bean yellow dwarf virus (BeYDV)-derived conditional replicative expression platform stably transformed in Nicotiana benthamiana and activated by copper sulfate (CuSO4), an inexpensive and widely used agricultural input. The CuBe system utilizes a synthetic circuit of four genetic modules integrated into the plant genome: (i) a replicative vector harboring the gene of interest (GOI) flanked by cis-acting elements for geminiviral replication and novelly arranged to enable transgene transcription exclusively upon formation of the circular replicon, (ii) copper-inducible Rep/RepA proteins essential for replicon formation, (iii) the yeast-derived CUP2-Gal4 copper-responsive transcriptional activator for Rep/RepA expression, and (iv) a copper-inducible Flp recombinase to minimize basal Rep/RepA expression. Copper sulfate application triggers the activation of the system, leading to the formation of extrachromosomal replicons, expression of the GOI, and accumulation of the desired recombinant protein. We demonstrate the functionality of the CuBe system in N. benthamiana plants expressing high levels of eGFP and an anti-SARS-CoV-2 antibody upon copper treatment. Notably, the system is also functional with post-harvest copper application, a strategy with potential advantages for large-scale biomanufacturing. This work presents the CuBe system as a promising alternative to agroinfiltration for cost-effective and scalable production of recombinant proteins in plants.

synthetic biology↗

bioRxiv2023

An atypical endomembrane localized CNL-type immune receptor with a conserved deletion in the N-terminal signaling domain functions in cell death and immunity

Plants have evolved intracellular nucleotide-binding leucine rich repeat receptors (NLRs) to induce a superior immune response. Upon activation, coiled-coil (CC) domain containing NLRs (CNLs) oligomerize to form apparent cation channels that promote calcium influx and cell death induction, with the alpha-1 helix of the individual CC domains penetrating membranes. Some members of a monophyletic subclass of CNLs, the ancient and autonomous NLRs (ANLs), are characterized by putative N- myristoylation and S-acylation sites at the N-terminus of their CCG10/GA domain, potentially mediating permanent membrane association. Whether these Potentially Membrane Localized NLRs (PMLs) mediate cell death upon activation in a similar way as reported for other CNLs has been unknown. We integrated phylogenetic, cell- biological, and functional studies to uncover the cell death function of an atypical but conserved Arabidopsis PML, PML5, which has a 113 amino acid deletion in its CCG10/GA domain. Active PML5 oligomers localize in Golgi membranes and the tonoplast, changes vacuolar morphology, and induce cell death, with the short N- terminus being sufficient for cell death. Mutant analysis supports a potential key role of PMLs in plant immunity. Similar deletions as in Arabidopsis PML5 are found in several Brassicales paralogs, pointing to the evolutionary importance of this innovation. PML5 is thus a naturally occurring CNL variant with a minimal signaling domain and its further study should help in understanding the functional importance of this minimal domain for NLR signaling.

plant biology↗

bioRxiv2022

A plant virus causes symptoms through the deployment of a host-mimicking protein domain to attract the insect vector

Viruses are obligate intracellular parasites with limited proteomes that heavily rely on the cell molecular machinery for their multiplication and spread. Plant viruses frequently cause symptoms through interference with host developmental programs. Despite the agricultural relevance of symptom development in virus-infected crops, the molecular mechanisms underlying these viral effects remain elusive. Here, we show that the symptoms triggered by tomato yellow leaf curl virus (TYLCV) depend on the physical interaction between the host-mimicking domain of a virus-encoded protein, C4, and a plant-specific family of RCC1-like domain-containing (RLD) proteins. C4 outcompetes endogenous interactors of RLDs, disrupting RLD function in the regulation of endomembrane trafficking and polar auxin transport, ultimately leading to the developmental alterations recognized as symptoms of the viral infection. Importantly, symptoms do not have a detectable effect on the performance of the virus in the plant host, but they serve as attractants for the viral insect vector, the whitefly Bemisia tabaci, hence promoting pathogen spread. Our work uncovers the molecular underpinnings of the viral manipulation that leads to symptom development in the TYLCV-tomato pathosystem, and suggests that symptoms have evolved as a strategy to promote viral transmission by the insect vector. Given that most plant viruses are insect-transmitted, the principles described here might have broad applicability to crop-virus interactions.

plant biology↗

bioRxiv2022

The transcriptional regulator JAZ8 interacts with the C2 protein from geminiviruses and limits the viral infection in Arabidopsis

Jasmonates (JAs) are phytohormones that finely regulate critical biological processes, including plant development and defense. JASMONATE ZIM-DOMAIN (JAZ) proteins are crucial keeping JA-responsive genes in a repressed state. In the presence of JA-Ile, JAZ repressors are ubiquitinated and targeted for degradation by the ubiquitin/proteasome system, allowing the activation of the downstream transcription factors and, consequently, the activation of JA-responsive genes. A growing body of evidence has shown that JA signalling is crucial in defending against plant viruses and their insect vectors. Here, we describe the interaction of C2 proteins from two geminiviruses from the genus Begomovirus, tomato yellow curl Sardinia virus (TYLCSaV) and tomato yellow leaf curl virus (TYLCV), with the transcriptional repressor JAZ8 from Arabidopsis thaliana and its closest orthologue in tomato, SlJAZ9. Both JAZ and C2 proteins colocalize in the nucleus, forming discrete nuclear speckles. Overexpression of JAZ8 did not lead to altered responses to TYLCV infection; however, knock-down of JAZ8 favours the geminiviral infection in plants. Low levels of JAZ8 likely affect the viral infection specifically since JAZ8-silenced plants do not display developmental phenotypes nor present differences in their interaction with the viral insect vector. Our results show that JAZ8 interacts with geminiviral C2 proteins and exerts an anti-geminiviral effect.

plant biology↗

bioRxiv2022

Ralstonia solanacearum alters root developmental programs in auxin-dependent and independent manners

Microbial pathogens and other parasites can modify the development of their hosts, either as a target or a side effect of their virulence activities. The plant pathogenic bacterium Ralstonia solanacearum, causal agent of the devastating bacterial wilt disease, is a soil-borne microbe that invades host plants through their roots, and later proliferates in xylem vessels. In this work, we studied the early stages of R. solanacearum infection in the model plant Arabidopsis thaliana, using an in vitro infection system. In addition to the previously reported inhibition of primary root length and increase in root hair formation at the root tip, we observed an earlier xylem differentiation during R. solanacearum infection that occurs in a HrpG-dependent manner, suggesting that the pathogen actively promotes the development of the vascular system upon invasion of the root. Moreover, we found that the phytohormone auxin, of which the accumulation is promoted by the bacterial infection, is required for the R. solanacearum-triggered induction of root hair formation, but not earlier xylem differentiation. Altogether, our results shed light on the capacity of R. solanacearum to induce alterations of root developmental pathways and on the role of auxin in this process.

plant biology↗

bioRxiv2021

Combinatorial interactions between viral proteins expand the functional landscape of the viral proteome

As intracellular parasites, viruses need to manipulate the molecular machinery of their host cells in order to enable their own replication and spread. This manipulation is based on the activity of virus-encoded proteins. The reduced size of viral genomes imposes restrictions in coding capacity; how the action of the limited number of viral proteins results in the massive cell reprogramming observed during the viral infection is a long-standing conundrum in virology. In this work, we explore the hypothesis that combinatorial interactions expand the multifunctionality of viral proteins, which may exert different activities individually and when in combination, physical or functional. We show that the proteins encoded by a plant-infecting DNA virus physically associate with one another in an intricate network. Our results further demonstrate that these interactions can modify the subcellular localization of the viral proteins involved, and that co-expressed interacting viral proteins can exert novel biological functions in planta that go beyond the sum of their individual functions. Based on this, we propose a model in which combinatorial physical and functional interactions between viral proteins enlarge the functional landscape of the viral proteome, which underscores the importance of studying the role of viral proteins in the context of the infection.

plant biology↗