Syndrome "Basses Richesses" (SBR) is a rapidly emerging sugar beet disease in central Europe that has a severe economic impact on the sugar beet industry and thus requires control. The cultivation of tolerant varieties is a promising method to reduce SBR. Digital plant phenotyping can support the screening process for tolerant varieties by characterizing traits of interest and quantifying tolerance. This research provides foundational work for digitally phenotyping SBR. Morphological and spectral traits were analyzed with machine learning, supporting disease monitoring and screening for tolerant varieties under controlled conditions. A susceptible sugar beet variety was infected with the dominant causal agent of SBR, 'Candidatus Arsenophonus phytopathogenicus' (ARSEPH). Hyperspectral images of the canopy were recorded weekly between 20 and 62 days after inoculation and segmented by leaves and petioles. Sixty-seven days after inoculation, each leaf was two-dimensionally (2D) and each taproot three-dimensionally (3D) imaged by angle-corrected 2D imaging and structured-light 3D scans, respectively. The results indicated substantial decreases in leaf area (19.7%), leaf length (6.9%), leaf blade length (13.1%), and leaf blade width (12.1%) resulting from ARSEPH infection. The most important wavelengths for machine learning classification of ARSEPH-infected sugar beet were from the petioles (97% accuracy) in the range 623 to 659 nm and 421 to 432 nm. The 22 most relevant taproot 3D parameters were evaluated with Boruta-SHAP based on their importance to characterize SBR-induced taproot deformation. Certain value and spatial regions were characteristic, indicating thresholds for 3D parameters and taproot regions to analyze when comparing varieties. [Formula: see text] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY 4.0 International license.

Accurate monitoring of insect vectors is critical for managing Syndrome ‘basses richesses’ (SBR), a disease affecting sugar beet crops in Europe. This study presents a deep learning (DL) approach for the automated identification of Cixiidae planthoppers, the primary SBR vectors. Several DL architectures, including convolutional neural networks (CNN) and vision transformers, were benchmarked, leading to the selection of Inception-v3. This architecture was then used to develop two complementary models: the first to distinguish Cixiidae from other insect groups, and the second to classify species within Cixiidae, namely Pentastiridius leporinus, Hyalesthes obsoletus, and Reptalus spp. Discrimination among these species is essential, as they differ in their efficiency and role in transmitting SBR. The models were trained and validated on over 40,000 high-resolution insect images collected from sticky traps deployed in sugar beet and grapevine fields across Germany and Serbia between 2022 and 2024. Species labels were based on morphological identification and verified via DNA barcoding, and the resulting dataset was made publicly available. Statistical and visual model evaluation confirmed high performance and biological relevance. The first model achieved 94

The disease syndrome "basses richesses" (SBR) leads to a significant reduction in sugar beet biomass and sugar content, negatively affecting the sugar economy. The mechanistic understanding regarding growth and photoassimilates distribution within the sugar beet taproot diseased with SBR is currently incomplete. We combined two tomographic methods, magnetic resonance imaging (MRI) and positron emission tomography (PET) using 11C as tracer, to non-invasively determine SBR effects on structural growth and photoassimilates distribution within the developing taproot over six weeks. MRI analysis revealed a deformed cross-sectional anatomical structure from an early stage, as well as a reduction in taproot volume and width of inner cambium ring structures of up to 26 and 24 ​%, respectively. These SBR disease effects were also confirmed by post-harvest analysis of the taproot. PET analysis revealed a heterogeneous distribution of labeled photoassimilates for diseased plants: sectors of the taproot with characteristic SBR symptoms showed little to very low 11C tracer signal. The heterogeneity of SBR disease effects is most likely due to a partial inoculation of leaves leading to an uneven distribution of the SBR pathogen in the taproot through the strong vascular interconnection between shoot and root. Also, the pathogen needs to spread non-uniformly within the taproot to explain the observed marked increase of the SBR disease effects over time. Our results indicate that SBR affects photoassimilates sink capacity at an early stage of taproot development. Co-registration of MRI and PET may support an early judging of susceptibility and selection of promising genotype candidates for future breeding programs.

Intermolecular recombination is a critical process in the evolution of plant viruses, including geminiviruses. In this study, we investigated the impact of geminiviral factors on the homologous recombination frequency (HRF) in a model system involving replicons of the beet curly top virus (BCTVRepl) and the cotton leaf curl Multan betasatellite (CLCuMB), which lacks the βC1 gene. BCTVRepl-cGFP and CLCuMB-nGFP replicated together and exhibited intermolecular recombination, which was monitored by reconstituted GFP fluorescence. Mutation of the C2, C3, and C4 genes in BCTVRepl-cGFP led to a significant decrease in HRF. Accumulation of BCTVRepl-cGFP was reduced in the C3 mutant but not in the C2 and C4 mutants. These findings suggest that C4 and, to a greater extent, C2 play a role in homologous recombination (HR) between BCTV and CLCuMB replicons. Furthermore, the BCTV large intergenic region (LIR) sequence to which the C1 (Rep) protein binds to initiate viral replication was introduced into the nGFP construct (referred to as LnGFP). This resulted in a low level of HR (5%) compared to the control nGFP construct, where HR did not occur. Subsequent mutational analysis of the iteron and stem-loop sequences within the LIR of LnGFP revealed the role of these sequences and the C1 (Rep) in the process of DNA recombination. This study presents a new model for assessing HRF in BCTV, which can be applied to other geminiviruses. It also highlights the roles of the C2, C4, C1, and LIR structural sequences in intermolecular recombination and replication in the BCTV replicon.IMPORTANCEIntermolecular recombination is a critical process in the evolution, adaptability, and pathogenicity of plant viruses, including geminiviruses. This study developed a visible and quantifiable system to measure the frequency of homologous recombination between beet curly top virus (BCTV) and cotton leaf curl Multan betasatellite (CLCuMB) replicons based on the reconstitution of GFP fluorescence. Furthermore, mutation analysis of complementary-sense genes in the BCTV replicon indicated that C4 and, to a greater extent, C2 play a role in the recombination between the BCTV and CLCuMB replicons. Subsequent mutational analysis of the iteron and stem-loop sequences within the large intergenic region of BCTV revealed the possible role of these structural sequences in the recombination process.

Phytoplasmas were detected in potato tubers and sugar beet roots in neighbouring fields in Southern Germany using quantitative PCR. Infected potato plants showed phytoplasma-associated symptoms including yellowing, upward leaf rolling, aerial tubers and early senescence. Sugar beet plants showed similar symptoms to those of syndrome 'basses richesses' (SBR) disease, including proliferation, yellowing and necrosis of older leaves. The genetic diversity of the phytoplasmas in the symptomatic potato and sugar beet plants was investigated through sequence analysis of 16S rRNA and stamp, vmp1, tuf and secY genes. The RFLP profiles and sequences of 16S rRNA were identical among all the sugar beet-positive samples and aligned with subgroup 16SrXII-P, whereas the potato phytoplasma strains were identified as belonging to subgroup 16SrXII-A. Sequence analysis of the non-ribosomal genes showed that the potato strains belonged to the b1 group of the tuf gene, the V4 and V17 groups of the vmp1 gene and the secY3 and secY4 groups of the secY gene. However, the sugar beet strain was clearly distinct from the potato strains. Together with strain 916/22 from sugar beet in eastern Germany, they formed a new group of tuf, secY, vmp and stamp genes. RFLP assays and multilocus sequence analysis of non-ribosomal genes of the phytoplasma strains confirmed that the potato phytoplasma strains were molecularly different from the sugar beet phytoplasma strains. In addition, this is the first report on the multilocus sequence analysis of 'Candidatus Phytoplasma solani' strains in potato plants in Germany, suggesting differences in source plants other than sugar beet or interactions with insect vectors specific to each crop.

This study investigates the potential of Trichoderma harzianum to mitigate the effects of Beet curly top Iran virus (BCTIV) on tomato plants. Tomato seedlings at the four-leaf stage were treated with a T. harzianum suspension and subsequently agroinoculated with a BCTIV infectious clone. The experiment included four treatments: mock plants (C), BCTIV-inoculated plants (V), Trichoderma-treated plants (T), and plants both infected with BCTIV and treated with Trichoderma (TV). Three weeks post-inoculation, symptom development and virus accumulation were assessed. At 45 days post-inoculation, root colonization by T. harzianum was confirmed. The disease severity index indicated a significant reduction in TV plants compared to V plants. Virus accumulation was also significantly lower in TV plants. Real-time PCR analysis showed increased expression of defense-related genes (HSP90, AGO2a, PR1) in TV plants, suggesting enhanced plant defense responses. Additionally, TV plants exhibited the highest fresh and dry weight among all groups. The presence of T. harzianum spores in the roots of TV plants confirmed successful colonization. These findings demonstrate that T. harzianum enhances tomato resistance to BCTIV by activating plant defense mechanisms, reducing disease severity and viral replication, promoting healthier growth and greater biomass in the treated tomato plants.

Pentastiridius leporinus (Hemiptera: Cixiidae) is the main vector of an emerging and fast spreading sugar beet disease, the syndrome ‘basses richesses’ (SBR), in different European countries. The disease is caused by the γ-3-proteobacterium ‘ Candidatus Arsenophonus phytopathogenicus’ and the phytoplasma ‘ Candidatus Phytoplasma solani’ which are exclusively transmitted by planthoppers and can lead to a significant loss of sugar content and yield. Monitoring of this insect vector is important for disease management. However, the morphological identification is time consuming and challenging as two additional cixiid species Reptalus quinquecostatus and Hyalesthes obsoletus with a very close morphology have been reported in sugar beet fields. Further, identification of females and nymphs of P. leporinus at species level based on taxonomic key is not possible. In this study, an isothermal nucleic acid amplification based on recombinase polymerase amplification (RPA) was developed to specifically detect P. leporinus. In addition, real-time RPA was developed to detect both adults (male and female) and nymph stages using pure or crude nucleic acid extracts. The sensitivity of the real-time RPA for detection of P. leporinus was comparable to real-time PCR, but a shorter time (< 7 min) was required. This is a first report for real-time RPA application for P. leporinus detection using crude nucleic acid templates which can be applied for fast and specific detection of this vector in the field.

The complete genome of "Candidatus Phytoplasma solani" GOE was obtained from the infected vector Pentastiridius leporinus by single-molecule real-time sequencing. This 16SrXII-P phytoplasma is associated with the economically important sugar beet disease "syndrome basses richesses." The genome sequence is an essential resource for diagnosis and understanding pathogen-host interaction.

Syndrome ‘basses richesses’ (SBR) disease in sugar beet caused by two phloem-limited pathogens, 'Candidatus Arsenophonus phytopathogenicus' and 'Candidatus Phytoplasma solani' is a fastspreading disease in Central Europe. The planthopper vector, Pentastiridius leporinus (Cixiidae), has recently expanded its host range to potato in Germany. However, the genetic diversity of 'Ca P. solani' in potato and possible association to SBR phytoplasma is unknown. In this study we charachterized ‘Ca. P. solani’ infecting sugar beet and potato plants in close distance fields in Southern Germany. Initially, the pathogen was detected in the potato tubers (18.7%) and sugar beet roots (60%) using TaqMan Real-Time PCR. Then, the sequences of 16S rRNA and other informative genes (stamp, vmp1, tuf and secY) were analysed in a number of infected potato and sugar beet plants. The phytoplasma strain infecting sugar beet in Southern Germany was classified into 16SrXII-P subgroup, a novel subgroup recently reported from sugar beet in Eastern Germany. While, the potato related strains were close to 16SrXII-A, which is a common subgroup for potato stolbur reported in Europe. The multilocus sequence analysis (MLSA) of non-ribosomal genes of the phytoplasma strains showed that the potato strain is clearly different from the sugar beet associated strain in this region. The presence and prevalence of 16SrXII-P in sugar beet in Southern and Eastern Germany suggests that this subgroup is dominant in sugar beet in Germany. In addition, this study elucidates for the first time, the genetic diversity of ‘Ca. P. solani’ strains in potato in Germany with a possible different source rather than sugar beet. Further investigation is required to investigate genetic variation of ‘Ca. P. solani’ in all sugar beet and potato-growing regions including weeds host in Central Europe to better understand the epidemiology of both sugar beet SBR and potato stolbur disease.

A tomato-infecting virus known as Beet curly top Iran virus (BCTIV) cause a significant disease for tomato plants and several other plant species around the world. Chitosan polysaccharide is a natural biopolymer that has been utilised as an exo-elicitor to enhance plant defence mechanisms against a variety of plant diseases. This study investigates the efficacy of chitosan in combating BCTIV disease on tomato plants and modulating the host-virus interaction under greenhouse conditions. Twenty-four hours before the virus inoculation, tomato plants were sprayed with a protective chitosan solution at different concentrations (0.5, 1, 1.5, and 2 mg/mL). Tomato plants were inoculated with a BCTIV infectious clone using an Agrobacterium-inoculation method. The findings clearly demonstrated a reduction in the severity of the disease in chitosan-treated plants as compared to Mock-plants, with the percentage decreasing from 61.53% to 75.28% in 1.5 mg/mL treated plants and from 9.01% to 28.43% in 0.5 mg/mL treated plants. In addition, the utilisation of chitosan has the potential to deactivate the accumulation of BCTIV within the host tissues. The virus accumulation was greatly alleviated in 1, 1.5, and 2 mg/mL-treated plants by 71.29%, 90.11%, and 93.14%, respectively, and over the mock plants. Furthermore, it was found that chitosan applied at all tested concentrations increased the relative expression and mRNA accumulation of genes related to resistance, including the pathogenesis-related protein gene PR-1, the HSP90 gene, and the AGO2a antiviral gene. These genes reached their maximum by 22.9-, 12.93-, and 4.44-fold increases, respectively, over the untreated control. According to gas chromatography-mass spectroscop (GC-MS) fractionation profile, chitosan increased 28 bioactive metabolic components, such as n-hexadecanoic acid, heptanone, 1,2-dimethylbenzene, dicarboxylic acid, and cis-11-octadecenoic acid methyl-ester, to improve metabolic pathways. Results reported here revealed that foliar application of chitosan decreases the rate of the disease severity and virus accumulation in BCTIV-infected tomato plants. This effect is associated with increased gene expression and defence-related factors, enhancing tomato resistance to BCTIV infection. Consequently, chitosan treatments could be part of an integrated approach for reducing the severity of BCTIV disease in tomato and other host plants.

Curly top disease caused by Beet curly top virus (BCTV) is a limiting factor for sugar beet production. The most economical and sustainable control of BCTV in sugar beet would be via the growth of resistant cultivars, although most commercial cultivars possess only low-to-moderate quantitative resistance. A double haploid line (KDH13) showed a high level of resistance to BCTV infection. However, the mechanism of resistance and response of this line to BCTV infection is unknown. Here, we tested the response of this line to both local and systemic BCTV infections. The virus replicated at a high level in locally infected tissue but lower than in susceptible KDH19 plants. Resistant KDH13 plants systemically infected with BCTV showed only mild enation without leaf curling after 30 days. In contrast, severe leaf curling appeared after 12 days in susceptible plants with higher virus accumulation. Transcriptome analysis of the BCTV-infected KDH13 plants at the early stage of symptom development showed only 132 genes that were exclusively deregulated compared to the regulation of a large number of genes (1018 genes) in KDH19 plants. Pathway enrichment analysis showed that differentially expressed genes were predominantly involved in hormone metabolism, DNA methylation, immune response, cell cycle, biotic stress and oxidative stress. The auxin level in both resistant and susceptible plants increased in response to BCTV infection. Remarkably, exogenous application of auxin caused leaf curling phenotype in the absence of the virus. This study demonstrates the response of resistant and susceptible plants to BCTV infection at both local and systemic infections and highlights the defence-related genes and metabolic pathways including auxin for their contribution towards BCTV symptom development and resistance in sugar beet.

Goal: production of antibodies against the coat protein of Apple stem grooving virus and their application in diagnostic assays and biosensor design represents a crucial strategy for effective plant virus detection. ASGV is a significant pathogen affecting pome fruit trees. The objective of this study was to express the coat protein gene of ASGV in E. coli, generate antibodies against the expressed protein, and assess their effectiveness in diagnostic assays.Methods: In the PCR, we successfully amplified a 714 bp fragment corresponding to the complete coding region of the ASGV coat protein gene. The amplified fragment was then cloned into the pTG19 vector. Subsequently, the desired fragment was subcloned into the pET28a (+) expression vector using BamHI and EcoRI restriction enzymes. The resulting construct was then introduced into E. coli BL21(DE3) cells for gene expression. To determine the optimal conditions for protein expression, the transformed cells were induced with one mM IPTG for various durations (3, 4, 6, and 16 hours). The expression of the protein was confirmed through SDS-PAGE electrophoresis and western blot analysis. Following the purification of the expressed protein, it was utilized as an antigen for immunizing rabbits. Immunoglobulins (IgGs) were subsequently purified from the rabbit serum, and some of them were employed for conjugate production. The efficacy of the conjugates was evaluated in serological assays.Results: Sequencing analysis of the amplified fragments conclusively verified their correspondence to the ASGV coat protein gene. Moreover, PCR and enzymatic digestion of the resulting clone provided further evidence of the successful construction of pET28-ASGV-CP. Comprehensive sequence analysis of the constructed plasmid in both directions confirmed the accurate insertion of the coat protein gene into the expression vector, while also confirming the absence of any nucleotide mutations. Following optimization, the expression of the ASGV coat protein was successfully achieved, resulting in an approximate size of 27 kDa. This confirmation was attained through SDS-PAGE electrophoresis and subsequent western blotting, conducted four hours after induction. The direct, indirect, and dot-blot assays were performed to assess the efficiency of the conjugate. The results indicated that the optimal concentration of the conjugate was approximately 1:1000.Conclusion: The generated and conjugated antibodies exhibit suitable titers relative to the antigen concentration and demonstrate specificity and effectiveness in the detection and identification of Apple stem grooving virus (ASGV). These antibodies can be utilized for various serological diagnostic kits, including ELISA, offering valuable applications in virus detection and identification.

Beet curly top Iran virus (BCTIV) is a yield-limiting geminivirus belonging to the becurtovirus genus. The genome organization of BCTIV is unique such that the complementary strand of BCTIV resembles Mastrevirus, whereas the virion strand organization is similar to the Curtovirus genus. Geminiviruses are known to avoid the plant defense system by suppressing the RNA interference mechanisms both at the transcriptional gene silencing (TGS) and post-transcriptional gene silencing (PTGS) levels. Multiple geminivirus genes have been identified as viral suppressors of RNA silencing (VSR) but VSR activity remains mostly elusive in becurtoviruses. We found that BCTIV-V2 and -Rep could suppress specific Sense-PTGS mechanisms with distinct efficiencies depending on the nature of the silencing inducer and the target gene. Local silencing induced by GFP inverted repeat (IR) could not be suppressed by V2 but was partially reduced by Rep. Accordingly, we documented that Rep but not V2 could suppress systemic silencing induced by GFP-IR. In addition, we showed that the VSR activity of Rep was partly regulated by RNA-dependent RNA Polymerase 6 (RDR6), whereas the VSR activity of V2 was independent of RDR6. Domain mapping for Rep showed that an intact Rep protein was required for the suppression of PTGS. In summary, we showed that BCTIV-Rep and -V2 function as silencing suppressors with distinct modes of action.

Genome editing using CRISPR/Cas is rapidly being developed for gene targeting in eukaryotes including plants. However, gene targeting by homology-directed DNA recombination (HDR) is an infrequent event compared to the dominant DNA repair by non-homologous end-joining. Another bottleneck is the ineffective delivery of CRISPR/Cas components into plant cells. To overcome these constraints, here a geminiviral replicon from Beet curly top virus (BCTV) has been produced with a wide host range and high DNA accumulation capacity for efficient delivery of CRISPR/Cas12a components into plant cells. Initially, a BCTV replicon was prepared after removing the virion sense genes from an infectious full-length clone for agrobacterium mediated infection. This replicon expressed a green fluorescent protein (GFP) marker gene at a high level compared to T-DNA binary vector. In transient assay, the BCTV replicon produced a higher rate of mutagenesis and HDR in the GFP transgene in Nicotiana benthamiana through efficient delivery of CRISPR/Cas12a components compared to the cognate T-DNA control. This was through a range of complete or partial HDR for conversion of GFP into YFP after exchange of a single amino acid (Thr224Tyr) in the target gene. In addition, induced mutagenesis and HDR in the target gene were heritable. Thus, the BCTV replicon provides a new tool for efficient delivery of CRISPR/Cas12a components that could be used in a wide range of dicotyledonous plants. The established GFP to YFP system and the GFP mutant line produced also enable further optimization and understanding of HDR in plants via CRISPR/Cas12a system using geminiviral replicons.

Beet curly top Iran Virus (BCTIV) is a yield-limiting geminivirus belonging to the becurtovirus genus. The genome organization of BCTIV is unique such that the complementary strand of BCTIV resembles mastreviruses, whereas the virion strand organization is close to curtoviruses. Geminiviruses are known to avoid the plant defense system by suppressing the RNA interference mechanisms both at the transcriptional gene silencing (TGS) and post-transcriptional gene silencing (PTGS) level. Multiple geminivirus genes have been identified as viral suppressors of RNA silencing (VSR) but VSR activity remains elusive in becurtoviruses. By screening all verified open reading frames in the BCTIV genome, we found that only V2 and Rep were able to suppress specific PTGS mechanisms, triggered by the expression of a partial or full-length sense-strand transcript of the target gene (S-PTGS). BCTIV-V2 could suppress S-PTGS more efficiently than BCTIV-Rep when then the target GFP gene is transiently expressed. On the other hand, S-PTGS is suppressed by Rep but not V2 when target GFP is only stably expressed. Deletional mutagenesis of BCTIV-Rep implicated that multiple domains are required for its VSR activity. Furthermore, neither V2 nor Rep could fully suppress local PTGS induced by inverted repeat targeting GFP (GFP-IR). Also, in a closer look at the spread of local silencing by GFP-IR, we observed that V2 or Rep are not able to suppress the movement of sRNAs. Nevertheless, Rep suppressed the systemic silencing induced by GFP-IR in 16C plants. Northern blot analyses showed that BCTIV-Rep inhibits silencing by mitigating sRNA production, whereas BCTIV-V2 does not alter sRNA levels. In summary, both the silencing phenotype and the molecular signatures of silencing implicate distinct modes of VSR activity of BCTIV-Rep and -V2. ### Competing Interest Statement The authors have declared no competing interest.

Beet curly top Iran virus (BCTIV) is a member of the genus Becurtovirus (Family Geminiviridae) with a circular single-strand DNA genome. BCTIV causes leaf curling and vein swelling symptoms in plants. However, the potential pathogenicity factor/s in BCTIV is/are not known. This study presents characterization of complementary-sense transcripts of BCTIV and the viral factors in directing the pathogenicity and hypersensitive response (HR) in Nicotiana benthamiana plants. In both local and systemic infection, splicing of the complementary transcripts of BCTIV was observed. Notably, a small number (8.3%) of transcripts were spliced to produce Rep (C1:C2) transcripts after deletion of 155 nt (position 1892-2046 from BCTIV). Expression of BCTIV genes in N. benthamiana using tobacco rattle virus (TRV)-based vector showed that Rep together with C1 are the main pathogenicity factors which cause typical viral leaf curling symptoms. In addition, the V2 caused a mild leaf curling, thickening, and asymmetric leaves, while the V1, V3, and C2 had no clear effect on the plant phenotype. Transient expression of individual viral genes showed that both the C1 and Rep trigger a HR response in N. benthamiana. The higher expression of HR marker genes, harpin-induced 1 (Hin1) and hypersensitivity-related (Hsr203JI), supported the role of C1 and Rep in HR response in plants. It is concluded that Rep and C1 are the main pathogenicity factors that also trigger HR response in plants.

Genome editing (GE) based on CRISPR/Cas (clustered regularly interspaced short palindromic repeats/CRISPR-associated protein) is rapidly being developed for gene targeting in eukaryotes including plants. CRISPR/Cas-based genome editing is precise, target specific, transgene-free, heritable and enables multiplex target modification in a short time. There are several examples for successful applications of GE for improving crop productivity. However, genome editing tools have not yet been used for sugar beet to tackle the negative effects of e.g. abiotic and biotic stresses on the crop production. Despite the constant progress in CRISPR/Casbased genome editing, the efficacy of precise genome editing through homologous DNA recombination (HDR), required to modify, insert or replace traits, is very low and challenging. Here, authors present several CRISPR/Cas-based approaches by considering recent advances and challenges for their application to improve crops including sugar beet.

Monitoring of Pentastiridius leporinus (Hemiptera: Auchenorrhyncha: Cixiidae), representing the main vector of the syndrome 'basses richesses' (SBR) disease in sugar beet is based on morphological identification. However, two other cixiid species, Reptalus quinquecostatus and Hyalesthes obsoletus with similar external characters are known to appear in sugar beet fields and are challenging to be distinguished from P. leporinus. We present a PCR-based method for species-specific detection of both male and female P. leporinus, directly after sweep net collection or after up to 18 months long term storage on sticky traps. Two methods of DNA template preparation, based on a commercial extraction kit or on simple grinding in phosphate-buffered saline (PBS) were compared. The latter method was also established for eggs and all five nymphal instars of P. leporinus from a rearing. Furthermore, in silico primer analysis showed that all Auchenorrhyncha species including far related species reported from sugar beet fields can be differentiated from P. leporinus. This was PCR-confirmed for the most common Auchenorrhyncha species from different German sugar beet fields. Sequence analysis of the P. leporinus mitochondrial cytochrome oxidase I gene (COI) amplicon showed a close relationship to COI from P. beieri but separated from the Reptalus and Hyalesthes species which are grouped into the same family Cixiidae. We present a sensitive, cost- and time-saving PCR-based method for reliable and specific detection of eggs and all nymphal instars, as well as male and female P. leporinus, after different methods of planthopper collection and template DNA template preparation that can be used in large scale monitoring assays.

Tomato bushy stunt virus (TBSV) and Tomato mosaic virus (ToMV) are important economic pathogens in tomato fields. Rhizoglomus irregulare is a species of arbuscular mycorrhizal (AM) fungus that provides nutrients to host plants. To understand the effect of R. irregulare on the infection by TBSV/ToMV in tomato plants, in a completely randomized design, five treatments, including uninfected control plants without AM fungi (C), uninfected control plants with AM fungi (M) TBSV/ToMV-infected plants without AM fungi (V), TBSV/ToMV-infected plants before mycorrhiza (VM) inoculation, and inoculated plants with mycorrhiza before TBSV/ToMV infection (MV), were studied. Factors including viral RNA accumulation and expression of Pathogenesis Related proteins (PR) coding genes including PR1, PR2, and PR3 in the young leaves were measured. For TBSV, a lower level of virus accumulation and a higher expression of PR genes in MV plants were observed compared to V and VM plants. In contrast, for ToMV, a higher level of virus accumulation and a lower expression of PR genes in MV plants were observed as compared to V and VM plants. These results indicated that mycorrhizal symbiosis reduces or increases the viral accumulation possibly via the regulation of PR genes in tomato plants.

The communication system in bacteria is mediated by chemical signal molecules in a process that is known as quorum sensing. Inactivation of this process, called quorum quenching (QQ), could be a potential strategy for controlling plant pathogenic bacteria. This study aimed to identify QQ bacteria as biocontrol agents against Pectobacterium carotovorum subsp. carotovorum (Pcc). For this purpose, the ability of obtained isolates from the rhizosphere to degrade acyl-homoserine lactone signalling molecules was investigated in the presence of gamma-caprolactone. In vitro and GC-MS analyses confirmed the consumption of GCL by some isolates which identified as species of Pseudomonas, Bacillus and Erwinia based on their phenotypic characteristics and partial 16S rRNA gene sequences and, Pseudomonas rhizosphaerae was introduced as QQ agent. Also, in vivo evaluation, Bacillus pumilus, Pseudomonas fluorescens and Pseudomonas sp. reduced soft rot in potato tubers by 98% as compared to the control inoculated with Pcc.