1,720,978 research outputs found
Effect of Environment and Sugar Beet Genotype on Root Rot Development and Pathogen Profile During Storage
No full textStorage rots represent an economically important factor impairing the storability of sugar beet by increasing sucrose losses and invert sugar content. Understanding the development of disease management strategies, knowledge about major storage pathogens, and factors influencing their occurrence is crucial. In comprehensive storage trials conducted under controlled conditions, the effects of environment and genotype on rot development and associated quality changes were investigated. Prevalent species involved in rot development were identified by a newly developed microarray. The strongest effect on rot development was assigned to environment factors followed by genotypic effects. Despite large variation in rot severity (sample range 0 to 84%), the spectrum of microorganisms colonizing sugar beet remained fairly constant across all treatments with dominant species belonging to the fungal genera Botrytis, Fusarium, and Penicillium. The intensity of microbial tissue necrotization was strongly correlated with sucrose losses (R² = 0.79 to 0.91) and invert sugar accumulation (R² = 0.91 to 0.95). A storage rot resistance bioassay was developed that could successfully reproduce the genotype ranking observed in storage trials. Quantification of fungal biomass indicates that genetic resistance is based on a quantitative mechanism. Further work is required to understand the large environmental influence on rot development in sugar beet
Effect of sugar beet variety resistance on the disease epidemiology of Cercospora beticola
No full textAbstract BACKGROUND Cercospora leaf spot (CLS), caused by Cercospora beticola , is the most destructive foliar disease in sugar beet. CLS is conventionally controlled with fungicide, but the emergence of fungicide‐resistant populations reinforces the importance of developing and cultivating resistant varieties. Understanding the dynamics of CLS in different varieties is hence essential for sustainable CLS management. RESULTS Field experiments (2022 and 2023) with four sugar beet varieties possessing different resistant properties were conducted to describe the relationship between the variety resistance and the disease epidemiology of C. beticola . For this purpose, spore flight and disease progression were assessed on a weekly basis. Disease severity (DS) and disease incidence (DI) were delayed in resistant varieties compared to the susceptible and moderately susceptible ones. This finding was further confirmed by a model‐based analysis of DS and DI for all varieties. Weekly spore flight monitoring during the vegetation period showed a similar tendency of reduced spore quantity by the resistant varieties. This was probably due to the lower DS, as no differences were found when the amount of fungal DNA was determined in individual lesions from the different varieties. Analysis of relative yield loss further confirmed the advantage of growing resistant varieties. CONCLUSION Our results highlight that resistant varieties delay disease onset resulting in less severe symptoms and reduced spore flight. We also proved that aerial spore flight intensity could reflect the resistant property of each variety. These results provide a deeper insight into the interaction between variety resistance and CLS epidemiology, emphasizing variety‐specific CLS management. © 2025 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.Bundesministerium für Ernährung und Landwirtschaft https://doi.org/10.13039/501100005908Fachagentur Nachwachsende Rohstoffe https://doi.org/10.13039/50110001081
Timing of fungicide application against Cercospora leaf spot disease based on aerial spore dispersal of Cercospora beticola in sugar beet
No full textAbstract Cercospora leaf spot is an important foliar disease in sugar beet caused by Cercospora beticola . Tolerant cultivars are available, but application of fungicides is still mandatory for disease control. The timing of the fungicide application is crucial as it determines the outcome of disease epidemiology. A disease incidence (DI) of 5% is widely used as a threshold for fungicide application. Recently a method was developed that allows the quantification of aerial spore dispersal of C . beticola for measuring spore flight intensity. It was aimed in this study to prove if fungicide application based on spore flight might improve disease control compared to DI. In a field trial with artificial inoculation, a single fungicide application at the onset of spore flight slowed down disease development as indicated by reduced disease severity and aerial spore dispersal. However, it did not provide sufficient control in terms of sugar yield. Only a second fungicide application based on spore flight detection achieved an efficacy similar to two fungicide applications based on DI. In contrast, a single fungicide application based either on spore flight or DI was sufficient in two on-farm trials under natural infection with moderate disease pressure. This highlights the necessity of an early timed first fungicide application followed by a second application under high disease pressure induced by artificial inoculation. Although fungicide application based on spore flight achieved sufficient control success in on-farm trials, it seems not to improve disease control compared to the usage of DI as threshold.BASF http://dx.doi.org/10.13039/100004349Georg-August-Universität Göttingen 50110000338
The arms race between beet necrotic yellow vein virus and host resistance in sugar beet
Full text linkBeet necrotic yellow vein virus (BNYVV) causes rhizomania disease in sugar beet (Beta vulgaris), which is controlled since more than two decades by cultivars harboring the Rz1 resistance gene. The development of resistance-breaking strains has been favored by a high selection pressure on the soil-borne virus population. Resistance-breaking is associated with mutations at amino acid positions 67-70 (tetrad) in the RNA3 encoded pathogenicity factor P25 and the presence of an additional RNA component (RNA5). However, natural BNYVV populations are highly diverse making investigations on the resistance-breaking mechanism rather difficult. Therefore, we applied a reverse genetic system for BNYVV (A type) to study Rz1 resistance-breaking by direct agroinoculation of sugar beet seedlings. The bioassay allowed a clear discrimination between susceptible and Rz1 resistant plants already four weeks after infection, and resistance-breaking was independent of the sugar beet Rz1 genotype. A comprehensive screen of natural tetrads for resistance-breaking revealed several new mutations allowing BNYVV to overcome Rz1. The supplementation of an additional RNA5 encoding the pathogenicity factor P26 allowed virus accumulation in the Rz1 genotype independent of the P25 tetrad. This suggests the presence of two distinct resistance-breaking mechanisms allowing BNYVV to overcome Rz1. Finally, we showed that the resistance-breaking effect of the tetrad and the RNA5 is specific to Rz1 and has no effect on the stability of the second resistance gene Rz2. Consequently, double resistant cultivars (Rz1+Rz2) should provide effective control of Rz1 resistance-breaking strains. Our study highlights the flexibility of the viral genome allowing BNYVV to overcome host resistance, which underlines the need for a continuous search for alternative resistance genes
Comparative analysis of virus pathogenicity and resistance-breaking between the P- and A-type from the beet necrotic yellow vein virus using infectious cDNA clones
No full textThe A-type of beet necrotic yellow vein virus (BNYVV) is widely distributed in Europe and is one of the major virus types causing rhizomania disease in sugar beet. The closely related P-type is mainly limited to a small region in France (Pithiviers). Both virus types possess four RNAs (RNA1–4), but the P-type harbours an additional fifth RNA species (RNA5). The P-type is associated with stronger disease symptoms and resistance-breaking of Rz1, one of the two resistance genes which are used to control BNYVV infection. These characteristics are presumably due to the presence of RNA5, but experimental evidence for this is lacking. We generated the first infectious cDNA clone of BNYVV P-type to study its pathogenicity in sugar beet in comparison to a previously developed A-type clone. Using this tool, we confirmed the pathogenicity of the P-type clone in the experimental host Nicotiana benthamiana and two Beta species, B. macrocarpa and B. vulgaris. Independent of RNA5, both the A- and the P-type accumulated in lateral roots and reduced the taproot weight of a susceptible sugar beet genotype to a similar extent. In contrast, only the P-type clone was able to accumulate a virus titre in an Rz1-resistant variety whereas the A-type clone failed to infect this variety. The efficiency of the P-type to overcome Rz1 resistance was strongly associated with the presence of RNA5. Only a double resistant variety, harbouring Rz1 and Rz2, prevented an infection with the P-type. Reassortment experiments between the P- and A-type clones demonstrated that both virus types can exchange whole RNA components without losing the ability to replicate and to move systemically in sugar beet. Although our study highlights the close evolutionary relationship between the two virus types, we were able to demonstrate distinct pathogenicity properties that are attributed to the presence of RNA5 in the P-type.</jats:p
Manipulation of auxin signalling by plant viruses
No full textCompatible plant-virus interactions result in dramatic changes of the plant transcriptome and morphogenesis, and are often associated with rapid alterations in plant hormone homeostasis and signalling. Auxin controls many aspects of plant organogenesis, development, and growth; therefore, plants can rapidly perceive and respond to changes in the cellular auxin levels. Auxin signalling is a tightly controlled process and, hence, is highly vulnerable to changes in the mRNA and protein levels of its components. There are several core nuclear components of auxin signalling. In the nucleus, the interaction of auxin response factors (ARFs) and auxin/indole acetic acid (Aux/IAA) proteins is essential for the control of auxin-regulated pathways. Aux/IAA proteins are negative regulators, whereas ARFs are positive regulators of the auxin response. The interplay between both is essential for the transcriptional regulation of auxin-responsive genes, which primarily regulate developmental processes but also modulate the plant immune system. Recent studies suggest that plant viruses belonging to different families have developed various strategies to disrupt auxin signalling, namely by (a) changing the subcellular localization of Aux/IAAs, (b) preventing degradation of Aux/IAAs by stabilization, or (c) inhibiting the transcriptional activity of ARFs. These interactions perturb auxin signalling and experimental evidence from various studies highlights their importance for virus replication, systemic movement, interaction with vectors for efficient transmission, and symptom development. In this microreview, we summarize and discuss the current knowledge on the interaction of plant viruses with auxin signalling components of their hosts.Open-Access-Publikationsfonds 202
Development of a DNA Microarray-Based Assay for the Detection of Sugar Beet Root Rot Pathogens
No full textSugar beet root rot diseases that occur during the cropping season or in storage are accompanied by high yield losses and a severe reduction of processing quality. The vast diversity of microorganism species involved in rot development requires molecular tools allowing simultaneous identification of many different targets. Therefore, a new microarray technology (ArrayTube) was applied in this study to improve diagnosis of sugar beet root rot diseases. Based on three marker genes (internal transcribed spacer, translation elongation factor 1 alpha, and 16S ribosomal DNA), 42 well-performing probes enabled the identification of prevalent field pathogens (e.g., Aphanomyces cochlioides), storage pathogens (e.g., Botrytis cinerea), and ubiquitous spoilage fungi (e.g., Penicillium expansum). All probes were proven for specificity with pure cultures from 73 microorganism species as well as for in planta detection of their target species using inoculated sugar beet tissue. Microarray-based identification of root rot pathogens in diseased field beets was successfully confirmed by classical detection methods. The high discriminatory potential was proven by Fusarium species differentiation based on a single nucleotide polymorphism. The results demonstrate that the ArrayTube constitute an innovative tool allowing a rapid and reliable detection of plant pathogens particularly when multiple microorganism species are present
Crop protection in sugar beet cultivation in Germany - Analysis of opportunities and challenges
No full textTaxonomic analysis of the microbial community in stored sugar beets using high-throughput sequencing of different marker genes
No full textCrop protection in sugar beet cultivation in Germany - Analysis of opportunities and challenges
No full text- …
