Search Results (226)

Viral infections and their vector dynamics pose a major threat to potatoes (Solanum tuberosum L.) worldwide, urgently needing an integrated understanding of the molecular and ecological interactions in this tripartite system. This review describes the major potato viruses, namely potato virus Y (PVY), the potato leafroll virus (PLRV), and potato virus X (PVX), with an emphasis on their infection and replication strategies in plants, as well as their movement within them. It also discusses plant responses to these viruses by uncovering RNA silencing, resistance (R) genes, and hormonal signaling. The complex dynamics of virus–vector interactions are discussed, considering the modes of transmission-persistent, non-persistent and semi-persistent—the role of viral proteins such as HC-Pro in determining vector specificity and adaptations in vectors that facilitate virus dissemination. This article discusses how vectors select potato plants, with an emphasis on the role played by plant-excreted volatiles and vector-applied saliva in plant defense. It also discusses host genes that contribute to vector resistance. This review provides an overview of the interactions between potato plants, viruses, and vectors and shows how viruses influence plant–vector interactions, the molecular pathways shared, and the altered gene expression profiles due to these interactions. The review offers an integrated perspective essential for developing sustainable and precise control strategies against potato viral pathogens under changing climatic conditions. Full article

Tomato yellow leaf curl virus (TYLCV) is a highly destructive pathogen of global tomato crops. The open reading frame (ORF) of TYLCV V2 contains two initiation codons (ATG1/V2-1 and ATG2/V2-2), producing distinct protein isoforms. Using custom antibodies, we confirmed V2-1 and V2-2 expression in infected Nicotiana benthamiana and tomato plants. Deletion mutants revealed their specialized roles: V2-1 was indispensable for viral replication and systemic spread—its loss severely reduced pathogenicity and genome accumulation. V2-2 acted as an auxiliary factor, and its deletion attenuated symptoms but kept the virus infection. Host-specific effects were observed—V2-1 deletion led to lower viral DNA/coat protein levels in N. benthamiana than in tomato, suggesting host-dependent regulation. Mutant viruses declined progressively in tomato, indicating host defense clearance. Heterologous co-expression of both isoforms via potato virus X induced systemic necrosis in N. benthamiana, demonstrating functional synergy between isoforms. Both initiation codons were essential for V2-mediated suppression of transcriptional gene silencing (TGS) and post-transcriptional gene silencing (PTGS). This study uncovers the mechanistic divergence of V2 isoforms in TYLCV infection, highlighting their collaborative roles in virulence and host manipulation. The findings advance understanding of geminivirus coding complexity and offer potential targets for resistance strategies. Full article

Insecticides are mainly used to control aphids as they are potatoes’ main vectors of viruses. This study analysed the flight activity of Myzus persicae, Phorodon humuli, and Aphis nasturtii from a suction trap over 22 years (2002–2024). We also analysed the flight activity of seven aphid species, vectors of viruses from the yellow water trap over 6 years (2019–2024). The number of catches of aphids in the suction trap was higher in 2014–2024 than in 2002–2013: for M. persicae, 4.2-fold, P. humuli 2.1-fold, and A. nastrurtii, 1.9-fold. A statistically significant correlation between mean temperature per year and total capture of M. persicae per year in the suction trap was found. The analysis showed no relationship between the abundance of M. persicae and P. humuli from the suction trap in spring and the abundance in the yellow water trap in the potato field. The dominant aphid species in the yellow water trap were M. persicae, Brevicoryne brassicae, and Aphis fabae. Regression analysis showed no direct relationship between aphid abundance in the yellow water trap over the period of 2019–2024 and seedling recruitment. Potato aphid control options are discussed concerning the flight activity and specific life cycles of each aphid species. Full article

Our knowledge of the molecular data on viruses infecting potato (Solanum tuberosum) and its weeds in Indonesia still needs to be expanded. Thirteen potato leaves, together with one carrot (Daucus carota subsp. sativus) and one Oxalis latifolia leaves grew adjacent to potato fields were sampled in West, Central, and East Java Provinces of Indonesia to be tested using RT-PCR with universal primers to monitor the presence of potyviruses, carlaviruses, and begomoviruses in the surveyed regions. According to the test results and BLAST nucleotide analysis, four potato samples were found to be infected by potato virus Y (PVY, Potyvirus). All samples tested negative for carlaviruses and begomoviruses. Both phylogenetic trees constructed by MEGA11 software based on partial coat protein and partial coat protein + 3′-UTR sequences demonstrated that the four new PVY isolates belong to strain N. Nucleotide and amino acid homology analysis determined that all four new and 12 other strain N isolates registered in NBCI GenBank were identical at the observed genome region, suggested the same origin of Indonesian isolates. This study improved our understanding of the variation in PVY isolates in Indonesia and highlighted the need for tight surveillance since the country imports most of its tubers used as planting material. Full article

Tomato yellow leaf curl disease poses one of the most severe threats to tomato production worldwide. This disease is associated with a group of closely related tomato yellow leaf curl viruses. These viruses can be transmitted by the sweet potato whitefly (Bemisia tabaci) in a persistent-circulative mode. Virus particles can infect the midgut and filter chamber of whiteflies feeding on infected plants, circulate in the hemolymph, and eventually infect the primary salivary gland (PSG) of whiteflies. Later, the whiteflies feed on healthy plants, and viral particles are introduced into the plants through their saliva. Virus–vector interactions play a crucial role in the efficiency and dynamics of virus transmission. In this study, we assessed the effects of the acquisition time and viral load of source plants on infections of two tomato begomoviruses, tomato yellow leaf curl Thailand virus (TYLCTHV) and tomato leaf curl Taiwan virus (ToLCTV), in B. tabaci Middle East–Asia Minor 1. We found that more viruses were acquired and accumulated in the whitefly midgut and PSG before reaching a plateau when the acquisition time increased and when the source plant had a higher viral load. The midgut and PSG acquired and accumulated more TYLCTHV than ToLCTV with the same acquisition time and regardless of the viral loads in coinfected source plants. These results not only help us to understand virus–vector interactions but also help in developing integrated disease management strategies. Full article

Phlox are ornamentals of great decorative value, grown throughout the world for their attractive flowers. Phlox cultivar collections at the Tsitsin Main Botanical Garden and the Botanical Garden of Lomonosov Moscow State University (both Moscow, Russia) were surveyed for virus diseases. Tobacco streak ilarvirus (TSV), beet ringspot nepovirus (BRSV), and BRSV satellite RNA (satRNA) were first detected in phlox when viromes of symptomatic Phlox paniculata plants were studied using high-throughput sequencing. The nearly complete genomes of three TSV and BRSV isolates and two BRSV satRNAs were assembled and characterized. TSV isolates shared 96.9–99.7% nucleotide sequence identity and were 82.2–89.1% identical to their closest relatives from broad bean, dahlia, and echinacea. BRSV isolates were distantly related to each other (83.7–89.3% identity) and were closest to those from oxalis and potato. BRSV satRNAs shared 90.6% identity and were 87.8–94.1% identical to satRNAs associated with tomato black ring virus L and S serotypes. Thus, TSV, BRSV, and BRSV satRNA were for the first time detected in a new natural host P. paniculata in Russia, adding to the list of known phlox viruses and expanding information on the host range, geographic distribution, and genetic diversity of these viruses. Full article

The potato is the third most important crop in the world, and more than 375 million metric tonnes of potatoes are produced globally on an annual basis. Potato Virus Y (PVY) poses a significant threat to the production of seed potatoes, resulting in economic losses and risks to food security. Current detection methods for PVY typically rely on serological assays for leaves and PCR for tubers; however, these processes are labor-intensive, time-consuming, and not scalable. In this proof-of-concept study, we propose the use of unmanned aerial vehicles (UAVs) integrated with hyperspectral cameras, including a downwelling irradiance sensor, to detect the PVY in commercial growers’ fields. We used a 400–1000 nm visible and near-infrared (Vis-NIR) hyperspectral camera and trained several standard machine learning and deep learning models with optimized hyperparameters on a curated dataset. The performance of the models is promising, with the convolutional neural network (CNN) achieving a recall of 0.831, reliably identifying the PVY-infected plants. Notably, UAV-based imaging maintained performance levels comparable to ground-based methods, supporting its practical viability. The hyperspectral camera captures a wide range of spectral bands, many of which are redundant in identifying the PVY. Our analysis identified five key spectral regions that are informative in identifying the PVY. Two of them are in the visible spectrum, two are in the near-infrared spectrum, and one is in the red-edge spectrum. This research shows that early-season PVY detection is feasible using UAV hyperspectral imaging, offering the potential to minimize economic and yield losses. It also highlights the most relevant spectral regions that carry the distinctive signatures of PVY. This research demonstrates the feasibility of early-season PVY detection using UAV hyperspectral imaging and provides guidance for developing cost-effective multispectral sensors tailored to this task. Full article

The family Alphaflexiviridae comprises plant- and fungus-infecting viruses with single-stranded, positive-sense RNA genomes ranging from 5.4 to 9 kb. Their virions are flexuous and filamentous, measuring 470–800 nm in length and 12–13 nm in diameter. The family includes 72 recognized species, classified into six genera: Allexivirus, Lolavirus, Platypuvirus, Potexvirus (plant-infecting), and Botrexvirus and Sclerodarnavirus (fungus-infecting). The genus Potexvirus is the largest, with 52 species, including Potexvirus ecspotati (potato virus X), an important crop pathogen and plant virology model. The genera are distinguished by genome organization and host range, while species differentiation relies on nucleotide and protein sequence identity thresholds. In this review, we summarize the current knowledge on the genomic structure, conserved genes, and phylogenetic relationships within Alphaflexiviridae, with a particular focus on the replicase and coat protein genes as signature markers. Additionally, we update the model of cellular remodeling driven by the triple gene block proteins, which are essential for virus movement, among other viral functions. Beyond their biological significance, alphaflexiviruses serve as valuable models for studying virus–host dynamics and hold potential applications in plant disease control and biotechnology. This review provides an updated framework for understanding Alphaflexiviridae and their broader impact on plant virology. Full article

High-throughput sequencing (HTS) was employed for the first time to investigate plant viruses infecting solanaceous crops, including potato (Solanum tuberosum), tomato (Solanum lycopersicum), and pepper (Capsicum annuum), in Kosovo. Leaf samples showing virus-like symptoms were collected from various regions during the summer of 2023. Based on ribodepleted RNA sequencing and bioinformatics analysis, six viruses were identified: cucumber mosaic virus, broad bean wilt virus 2 (BBWV2), potato virus Y, pepper cryptic virus 2 (PCV2), bell pepper endornavirus (BPEV), and ranunculus white mottle virus. BBWV2, PCV2, and BPEV are reported for the first time in the Balkan region. Virus presence was validated using RT-PCR. Phylogenetic analyses revealed that the identified viral strains did not cluster according to their hosts and geographical origins. CMV and BBWV2 variants exhibited reassortment events, indicating possible local evolution or novel virus introductions. This research highlights the widespread occurrence of mixed infections in pepper plants and highlights the need for additional research into the virus transmission dynamics and potential reservoir hosts. These findings emphasize the need for continuous surveillance and integrated plant protection strategies to mitigate the impacts of viral infections on pepper and other economically important crops in Kosovo. Full article

Groundnut bud necrosis orthotospovirus (GBNV), a tripartite single-stranded RNA virus, poses a significant threat to United States agriculture. GBNV is a quarantine pathogen, and its introduction could lead to severe damage to economically important crops, such as groundnuts, tomatoes, potatoes, peas, and soybeans. For the rapid and accurate detection of GBNV at points of entry, TaqMan reverse transcriptase–quantitative polymerase chain reaction (RT-qPCR) assays were developed and the results validated using conventional reverse transcriptase–polymerase chain reaction (RT-PCR) followed by Sanger sequencing. These assays target highly conserved regions of the nucleocapsid (NP) and movement (MP) proteins within the viral genome. Multiplex GBNV detection assays targeting the NP and MP genes, as well as an internal control plant gene, ACT11, showed efficiency rates between 90% and 100% and R² values of 0.98 to 0.99, indicating high accuracy and precision. Moreover, there was no significant difference in sensitivity between multiplex and singleplex assays, ensuring reliable detection across various plant tissues. This rapid, sensitive, and specific diagnostic assay will provide a valuable tool at ports of entry to prevent the entry of GBNV into the United States. Full article

The effects of the combination of the light intensity and photoperiod on the yield of virus-free potato and resource utilization are still poorly understood, especially under the same daily light integral. Here, we tested the responses of virus-free potato in terms of plant growth, photosynthesis, and the tuber yield to four light intensity and photoperiod combinations (T1, 200 μmol m⁻² s⁻¹ and 16.5 h; T2, 300 μmol m⁻² s⁻¹ and 11 h; T3, 400 μmol m⁻² s⁻¹ and 8.25 h; T4, 500 μmol m⁻² s⁻¹ and 6.6 h) under the same daily light integral. The tuber number and dry weight increased with the shortening of the photoperiod. The smaller number of tubers under the T1 treatment was due to the poor transport of photosynthates in the leaves and the uneven distribution of photosynthates in the tubers during the tuber formation stage. Changes in the light intensity and photoperiod combination did not significantly impact the distribution ratio of photosynthates between plants and tubers at the tuber growth stage; they only caused adjustments in the total amount of photosynthates. In addition, the photoinhibition under T1 was caused by the long photoperiod and that under T4 was caused by the high light intensity. However, the higher content of carotene in the T4 treatment alleviated the adverse effects of photoinhibition on the tuber yield. The results showed that the number and growth of tubers were extremely negatively correlated with shoot growth and extremely positively correlated with the accumulation rate of photosynthates in the plant and the tubers per day. In terms of energy consumption and the cost of the light source, we recommend the light intensity and photoperiod combinations of 300 μmol m⁻² s⁻¹ and 11 h or 400 μmol m⁻² s⁻¹ and 8.25 h to cultivate virus-free potato in plant factories. Full article

China, the largest global producer of sweet potatoes, faces significant threats from viral diseases, particularly in Fujian Province, where sweet potatoes are the second most important food crop after rice. This study identified 11 viruses, including sweet potato feathery mottle virus (SPFMV) and sweet potato chlorotic stunt virus (SPCSV), infecting sweet potatoes in Fujian. Sequence comparisons revealed diverse strains from various sources. Virus prevalence varied across regions, with Quanzhou, Fuzhou, and Putian severely affected, detecting 10, 9, and 7 viruses, respectively, compared to only 3 in Sanming and Longyan. In particular, sweet potato virus disease (SPVD) caused the most severe damage during the seeding stages, resulting in dwarfing and leaf deformation, while the damage was lighter during the growth period, manifesting as the yellowing and brittleness of the leaves, ultimately reducing the yield. Compound infestations predominated, with between 0 and 6 viruses infecting different sweet potato varieties. Single-virus infections were observed for sweet potato virus 2 (SPV2), sweet potato symptomless virus 1 (SPSMV-1), and sweet potato pakakuy virus (SPPV), while others, particularly SPCSV, were frequently co-infected with SPFMV, leading to SPVD development. Further analysis showed that the RNase3 expression of SPCSV was correlated with the SPVD severity in sweet potato. These findings provide insights into the epidemiology of sweet potato viruses and serve as a reference for developing targeted disease management strategies. Full article

Potatoes, a vital global food crop, have shown remarkable adaptability, significantly contributing to food security. Technological advancements now enable their cultivation from soil-based systems to liquid synthetic nutrient media, even in artificial closed environments without natural light or fertile soil. This study examined the effects of Benzylaminopurine (BAP) and Kinetin (Kin) at concentrations ranging from 0 to 5 mg/L and sucrose concentrations ranging from 20 to 120 g/L on in vitro tuberization, focusing on microtuber size, weight, and tuberization rate. Nodal segments from virus-free ‘Red Scarlet’ in vitro potato plantlets were used as explants. These explants were cultured on Murashige and Skoog (MS) medium solidified with 0.5% agar. The study also compared minituber production efficiency under soil-based greenhouse and aeroponic conditions. The highest in vitro potato tuberization rate (90%) was achieved with 80 g/L sucrose and 3.0 mg/L BAP. After induction, virus-free microtubers were transferred to both greenhouse conditions and aeroponic systems for further assessment of minituber production and biochemical composition. These findings demonstrate the potential of aeroponics as a superior method for producing high-quality, pathogen-free minitubers. Aeroponics resulted in significantly higher minituber yields compared to soil-based greenhouse systems, offering a scalable and efficient solution for seed production. Full article

Phytopathogens pose a serious threat to agriculture, causing a decrease in yield and product quality. This necessitates the development of methods for early detection of phytopathogens, which will reduce losses and improve product quality by using lower quantities of agrochemicals. In this study, the efficiency of spectral imaging in the early detection and differentiation of diseases caused by pathogens of different types (Potato virus X (PVX) and the bacterium Pseudomonas syringae) was analyzed. An evaluation of the visual symptoms of diseases demonstrated the presence of pronounced symptoms in the case of bacterial infection and an almost complete absence of visual symptoms in the case of viral infection. P. syringae caused severe inhibition of photosynthetic activity in the infected leaf, while PVX did not have a pronounced effect on photosynthetic activity. Reflectance spectra of infected and healthy plants were detected in the range from 400 to 1000 nm using a hyperspectral camera, and the dynamics of infection-induced changes during disease progression were analyzed. P. syringae caused a strong increase in reflectance in the blue and red spectral ranges, as well as a decrease in the near-infrared range. PVX-induced changes in the reflectance spectrum had smaller amplitudes compared to P. syringae, and were localized mainly in the red edge (RE) range. The entire set of normalized reflectance indices (NRI) for the analyzed spectral range was calculated. The most sensitive NRIs to bacterial (NRI_510/545, NRI_510/850) and viral (NRI_600/850, NRI_700/850) infections were identified. The use of these indices makes it possible to detect the disease at an early stage. The study of the identified NRIs demonstrated the possibility of using the multispectral imaging method in early pathogen detection, which has high performance and a low cost of analysis. Full article

Tobacco veinal necrosis caused by the potato virus Y (PVY) substantially affects yields and crop quality of tobacco. PVY shows high variability in virulence due to numerous mutations and recombinations. The types of resistance available for tobacco include the va type, effective against some PVY isolates but succumbing to others, and the Nicotiana africana-derived type, fully effective in its native genetic milieu but limited to varying degrees of tolerance when transferred to N. tabacum. The objective of this study was to evaluate the pyramiding potential of these two sources of resistance in alloploid hybrids of Nicotiana tabacum x N. africana. To this end, amphidiploids involving N. tabacum cvs. VAM and Wiślica, each being the carrier of a different variant of the va gene, were created and advanced from F₁ to two subsequent selfed generations and to BC₁ generation with either VAM or Wiślica as the recurrent N. tabacum parent. The hybrid populations thus produced were challenged with two PVY necrotic isolates, IUNG 23 and IUNG 20, mild and severe isolate belonging to the PVY^N-Wi and PVY^NTN groups, respectively. The mild isolate failed to infect any of the hybrids or parental species. The hybrids varied in their response to IUNG 20. The F₁ and F₂ populations were composed of asymptomatic hosts to PVY and of those showing mild vein clearing but no necrotic plants. There was a progressive increase in ability to resist PVY in successive amphidiploid generations, with 30 and 10% of fully resistant plants appearing in the F₃ amphidiploids involving VAM and Wiślica. Further research is needed to account for the appearance of segregants completely resistant to PVY, since neither N. africana factor is fully expressed in N. tabacum, nor do the va alleles confer resistance against PVY^NTN isolates. Full article