nanoVIR: Neue Viruserkrankungen in Erbsen und Ackerbohnen: Status quo-Analyse und Handlungsempfehlungen

Das Projekt war mit Untersuchungen zum wirtschaftlichen Status der neuen Viruserkrankung PNYDV (Pea necrotic yellow dwarf virus) in Erbsen (Pisum sativum L.) und Ackerbohnen (Vicia faba L.) befasst. An drei Standorten der Projektpartner Universität Kassel-FÖP, JKI Braunschweig und TI-OL Trenthorst wurden ferndiagnostische Verfahren zur Früherkennung und Schadenserfassung auf Praxisflächen und im Parzellenversuch erprobt. Bei Ackerbohnen wurden die Reflektionsmuster einzelner infizierter Pflanzen im Vergleich zu unsymptomatischen Kontrollpflanzen vermessen. Erstere waren entweder im Gewächshaus mittels virus-infizierter Erbsenblattläuse (Acyrthosiphon pisum) entweder PNYDV-, PEMV- (Pea enation mosaic virus), bzw. mischinfiziert, oder aus dem Kern natürlicher Infektionsnester. Hyper- und multispektrale Bildauswertungen früh PNYDV-infizierter Ackerbohnen ergaben gegenüber der Kontrolle Reflektionsunterschiede im sichtbaren und insbesondere im Nahinfrarotbereich. Erste Vegetationsindex-Berechnungen, wie GNDVI, ließen sich mit Ernteverlusten auf Praxisflächen schwach, aber signifikant korrelieren. Die Ergebnislage aller analogen Versuche zur fernoptischen Symptomerfassung mit Erbsen war insgesamt weniger konsistent. Das Gelbschalen-Monitoring zur Vektor-Phänologie und PNYDV-Virusfracht ergab für die in 5 Untergruppen eingeteilten Fänge von Erbsen-, Wicken- (Megoura viciae), Pfirischblattlaus (Myzus persicae), Aphis-sp.-Gruppe, und Sonstige, in allen Gruppen PNYDV-Nachweise, bis auf M. viciae, jedoch mit erheblichen Schwankungen und ohne erkennbares Muster. Die Punktinfektions-Methode lieferte reproduzierbare Primärinfektionen in Ackerbohnen und teilweise auch in Erbsen. Beide Ackerbohnensorten ’Fuego’ und ’GL-Sunrise’ erwiesen sich als PNYDV und PEMV anfällig. Aber nur bei ’Fuego’ ließ sich nach 7 Wochen sekundäre PNYDV-Ausbreitung auf Nachbarpflanzen bestätigen, während die sekundäre Ausbreitung bei ’GL-Sunrise’ gänzlich fehlte, was auf mögliche epidemiologische Sortenunterschiede bezüglich PNYDV hinweist. Im Gegensatz dazu, trat PEMV-Sekundärverbreitung bei beiden Sorten, sowohl rein- als auch mischinfiziert, auf. Insgesamt führten PNYDV-Einflüsse in Rein- und Mischinfektion zu signifikant geminderter Bildung intakter Wurzelknöllchen und geringerer Ertragsbildung in allen Gewächshaus- und Feldexperimenten sowie den on-farm Erhebungen in Ackerbohnen 2018. Alle genannten Aspekte sind weiter Untersuchungsgegenstand einer Projektverlängerung in 2019 und finden innerhalb des BÖLN (12OE012, 12OE035) statt

Complementary Strategies for Biological Control of Aphids and Related Virus Transmission in Sugar Beet to Replace Neonicotinoids

peer reviewedNeonicotinoid-based real control of aphids in sugar beet permitted the effective management of associated phytoviruses. However, the prohibition on their usage has prompted an urgent search for viable replacements. The development of sugar beet varieties with aphid and/or virus resistance and/or tolerance has a huge potential to reduce aphids and the harm caused by transmitted viruses. Semiochemicals also play a significant part in determining intra- and inter-specific interactions, which directly affect aphid fitness, feeding activity, and ultimately their capacity to spread viruses. Another method of aphid management involves the use of plant volatile organic compounds (VOCs) in conjunction with an attract and kill strategy. Entomopathogenic fungi could also be used to manage aphids without endangering helpful entomofauna. Finally, soil bacteria are particularly effective biocontrol agents because they induce systemic resistance (ISR) as plant growth promoting rhizobacteria (PGPR). The sugar beet-aphid virus model would be a perfect place to test these microbial players. The adoption of complementing eco-compatible techniques in the sugar beet crop will be ensured by the application of a variety of biocontrol opportunities connected to creative aphid control strategies. This should make it possible to create technical itineraries for a comprehensive approach to controlling aphids and related viruses depending on the situation

DRACULA2 is a dynamic nucleoporin with a role in regulating the shade avoidance syndrome in Arabidopsis

Altres ajuts: C.T. received a Marie Curie IEF postdoctoral contract funded by the European Commission.I.R.-V. received initiallyan FPIfellowship from the SpanishMINECO and later a Beatriu de Pinós contract from AGAUR. - Our research is supported by grants from Generalitat Valenciana [PROMETEO/2009/112, PROMETEOII/2014/006] to M.R.P. and J.L.M.When plants grow in close proximity basic resources such as light can become limiting. Under such conditions plants respond to anticipate and/or adapt to the light shortage, a process known as the shade avoidance syndrome (SAS). Following genetic screening using a shade-responsive luciferase reporter line (PHYB:LUC), we identified DRACULA2 (DRA2), which encodes an Arabidopsis homolog of mammalian nucleoporin 98, a component of the nuclear pore complex (NPC). DRA2, together with other nucleoporins, participates positively in the control of the hypocotyl elongation response to plant proximity, a role that can be considered dependent on the nucleocytoplasmic transport of macromolecules (i.e. is transport dependent). In addition, our results reveal a specific role for DRA2 in controlling shade-induced gene expression. We suggest that this novel regulatory role of DRA2 is transport independent and that it might rely on its dynamic localization within and outside of the NPC. These results provide mechanistic insights in to how SAS responses are rapidly established by light conditions. They also indicate that nucleoporins have an active role in plant signaling

Photoreceptor Activity Contributes to Contrasting Responses to Shade in Cardamine and Arabidopsis Seedlings

Plants have evolved two major ways to deal with nearby vegetation or shade: avoidance and tolerance. Moreover, some plants respond to shade in different ways; for example, Arabidopsis thaliana undergoes an avoidance response to shade produced by vegetation, but its close relative Cardamine hirsuta tolerates shade. How plants adopt opposite strategies to respond to the same environmental challenge is unknown. Here, using a genetic strategy, we identified the C. hirsuta slender in shade1 (sis1) mutants, which produce strongly elongated hypocotyls in response to shade. These mutants lack the phytochrome A (phyA) photoreceptor. Our findings suggest that C. hirsuta has evolved a highly efficient phyA-dependent pathway that suppresses hypocotyl elongation when challenged by shade from nearby vegetation. This suppression relies, at least in part, on stronger phyA activity in C. hirsuta; this is achieved by increased ChPHYA expression and protein accumulation combined with a stronger specific intrinsic repressor activity. We suggest that modulation of photoreceptor activity is a powerful mechanism in nature to achieve physiological variation (shade tolerance vs. avoidance) for species to colonize different habitats

On-farm Untersuchungen zum Nanovirus PNYDV (Pea necrotic yellow dwarf virus) an Ackerbohne (Vicia faba)

Pea necrotic yellow dwarf virus (PNYDV) ist ein neuer Nanovirus in Mitteleurope, der verschiedene Leguminosen befällt und persistent durch Blattläuse übertragen wird. In dieser on-farm Studie untersuchten wir sechs Ackerbohnen-Felder mit PNYDV-symptomatischen Nestern mittels multispektraler Drohnen-Aufnahmen, die mit ground-truth Pflanzenwachstumsparametern korreliert werden. Symptomatische Pflanzen zeigten einen signifikanten Rückgang der Sprosslänge, oberirdische Trockenmasse, Hülsenzahl sowie Anzahl und Trockenmasse N-fixierender Wurzelknöllchen. Im Gegensatz zu gesunden Pflanzen hatten symptomatische Pflanzen keine rosa oder rot gefärbten Knöllcheninhalte, stattdessen höhere Anteile zerfallender und inaktiver Knöllchen. Verschiedene Indices der multispektralen Aufnahmen zeigten einen deutlichen Unterschied in der spekteralen Information von symptomatischem Infektionsherd gegenüber der umgebenden Referenz

Novel multiple sclerosis susceptibility loci implicated in epigenetic regulation.

We conducted a genome-wide association study (GWAS) on multiple sclerosis (MS) susceptibility in German cohorts with 4888 cases and 10,395 controls. In addition to associations within the major histocompatibility complex (MHC) region, 15 non-MHC loci reached genome-wide significance. Four of these loci are novel MS susceptibility loci. They map to the genes L3MBTL3, MAZ, ERG, and SHMT1. The lead variant at SHMT1 was replicated in an independent Sardinian cohort. Products of the genes L3MBTL3, MAZ, and ERG play important roles in immune cell regulation. SHMT1 encodes a serine hydroxymethyltransferase catalyzing the transfer of a carbon unit to the folate cycle. This reaction is required for regulation of methylation homeostasis, which is important for establishment and maintenance of epigenetic signatures. Our GWAS approach in a defined population with limited genetic substructure detected associations not found in larger, more heterogeneous cohorts, thus providing new clues regarding MS pathogenesis

Low-Frequency and Rare-Coding Variation Contributes to Multiple Sclerosis Risk

Multiple sclerosis is a complex neurological disease, with 3c20% of risk heritability attributable to common genetic variants, including >230 identified by genome-wide association studies. Multiple strands of evidence suggest that much of the remaining heritability is also due to additive effects of common variants rather than epistasis between these variants or mutations exclusive to individual families. Here, we show in 68,379 cases and controls that up to 5% of this heritability is explained by low-frequency variation in gene coding sequence. We identify four novel genes driving MS risk independently of common-variant signals, highlighting key pathogenic roles for regulatory T cell homeostasis and regulation, IFN\u3b3 biology, and NF\u3baB signaling. As low-frequency variants do not show substantial linkage disequilibrium with other variants, and as coding variants are more interpretable and experimentally tractable than non-coding variation, our discoveries constitute a rich resource for dissecting the pathobiology of MS. In a large multi-cohort study, unexplained heritability for multiple sclerosis is detected in low-frequency coding variants that are missed by GWAS analyses, further underscoring the role of immune genes in MS pathology

Transmission activation in non-circulative virus transmission: a general concept?

BGPI : équipe 2International audienceMany viruses are transmitted by arthropod vectors. An important mode of transmission is the noncirculative or mechanical transmission where viruses attach to the vector mouthparts for transport to a new host. It has long been assumed that noncirculative transmission is an unsophisticated mode of viral spread, and in the simplest case mere contamination of the vector mouthparts. However, emerging evidence strongly suggests that noncirculative transmission, like other transmission strategies, results from specific interactions between pathogens, hosts, and vectors. Recently, new insights into this concept have been obtained, by demonstrating that a plant virus responds instantly to the presence of its aphid vector on the host by forming transmission morphs. This novel concept, named Transmission Activation (TA), where viruses respond directly or via the host to the outside world, opens new research horizons

Looking for elicitors and receptors of cauliflower mosaic virus (CaMV) transmission activation

BGPI : équipe 2Looking for elicitors and receptors of cauliflower mosaic virus (CaMV) transmission activation. 6. Joint Meeting of the DPG working Group “Virus Diseases of Plants” and the “Nederlandse Kring voor Plantevirologie