Carl Jonas Jorge Spetz
Research Scientist
Authors
Wiktoria Kaczmarek-Derda Trygve S. Aamlid Ingerd Skow Hofgaard Tatsiana Espevig Khaled Murad Agha Anette Sundbye Zahra Bitarafan Kirsten Tørresen Heidi Udnes Aamot Andrea Ficke Gunda Thöming Annette Folkedal Schjøll Håvard Eikemo Anne Muola Therese With Berge Belachew Asalf Tadesse Jorunn Børve Arne Stensvand Nina Trandem Gunnhild Jaastad Bjørn Arild Hatteland Katherine Ann Gredvig Nielsen Nina Johansen Charles Kwadha Inger Sundheim Fløistad Martin Pettersson Zhibo Hamborg Carl Jonas Jorge Spetz Dag-Ragnar Blystad Özgün Candan Onarman Umu Marit Skuterud Vennatrø Jan Philip Øyen Solveig Haukeland Tor-Einar Skog Roger Holten Anne Straumfors Valborg Kvakkestad Line Ulberg Tveiten Ingrid FlatlandAbstract
I Jordbruksoppgjøret 2025 (Prp. 149 S (2024 – 2025)) ble det enighet om at kunnskapsstatus og -behov innen plantehelseområdet fra 2019 måtte oppdateres. Det er gjort i form av denne rapporten. Den bestilte utredningen er avgrenset til skadegjørere og planteverntiltak som er relevante for jord- og hagebruk. Utredingen tar for seg kunnskap, prosjekter og kunnskapshull siden 2019 og fram til i dag (2026). Kapittel 1 omtaler metodebruk og plantevern i et beredskapsperspektiv. Kapittel 2.1-2.8 omhandler status for utfordringer med skadegjørere og tilgang til planteverntiltak for alle aktuelle plantekulturer for ugras, skadedyr og sopp. Kapittel 2.9 gir en oversikt over godkjente og utgåtte plantevernmidler siden 2019. Kapittel 2.10 omhandler skadegjørere hvor kjemiske plantevernmidler er i begrenset bruk. Det vil si virus, bakterier og nematoder. Kapittel 3 tar for seg ny teknologi og innovative metoder for integrert plantevern og faktorer som påvirker bruken av disse. Kapittel 4 omhandler miljø- og helseeffekter knyttet til bruk av kjemiske plantevernmidler, hvilke plantekulturer som utgjør størst risiko for negative miljøeffekter og faktorer som reduserer helserisikoen. Kapittel 5 tar for seg næringens behov og utviklingstrekk knyttet til kunnskap, rådgivning og tiltak. Dette kapittelet ser også på årsaker til eventuelle endringer i bruk av og behov for plantevernmidler som følge av for eksempel miljøkrav.
Abstract
Viroids are the smallest known nucleic acid‐based infectious agents of plants and consist of single‐stranded, circular, non‐coding RNAs that can cause significant crop diseases. The potato spindle tuber viroid (PSTVd), a model Pospiviroidae member, severely impacts Solanaceous hosts like potato and tomato, causing substantial yield reductions. Its 359‐nucleotide, rod‐like genome, with five functional domains, mediates nuclear replication, systemic movement via plasmodesmata and phloem, and evasion of host RNA silencing. High mutation rates generate diverse quasi‐species, enhancing adaptability. Recent multi‐omics studies reveal PSTVd reprogramming of host transcriptomes, epigenomes, and metabolomes, disrupting defence, hormone signalling, and photosynthesis. Within the plant holobiont, PSTVd modulates interactions with viruses, notably via RNA‐directed DNA methylation, and may affect rhizosphere microbial communities indirectly via changes in host physiology, an area that remains poorly resolved. This review synthesises advances in PSTVd structure, infection mechanisms, and holobiont interactions, highlighting its role in uncovering RNA‐mediated pathogenesis principles. Key knowledge gaps persist regarding host factors facilitating systemic spread and interactions with other organisms, such as microbial communities. Ongoing PSTVd research is essential to address this gap and guide strategies for viroid‐resistant crops and sustainable control.
Authors
Richita Saikia Athanasios Kaldis Carl Jonas Jorge Spetz Basanta Kumar Borah Andreas VoloudakisAbstract
Plant viruses utilize a subset of host plasmodesmata-associated proteins to establish infection in plants. In the present study, we aimed to understand the role of two plant genes, one encoding a putative plasmodesma located protein (PDLP) and a homolog of soybean gene regulated by cold 2 protein (SRC2) during Cucumber mosaic virus (CMV) infection. Virus-induced gene silencing (VIGS) was used to silence PDLP and SRC2 genes in Nicotiana benthamiana and in two related solanaceous plants, N. tabacum and Capsicum chinense Jacq. (Bhut Jolokia). Up to 50% downregulation in the expression of the PDLP gene using the TRV2-PDLP VIGS construct was observed in N. benthamiana and N. tabacum while, using the same gene construct, 30% downregulation of the target mRNA was observed in C. chinense. Similarly, using the TRV2-SRC2 VIGS construct, a 60% downregulation of the SRC2 mRNA was observed in N. benthamiana, N. tabacum, and a 40% downregulation in C. chinense as confirmed by qRT-PCR analysis. Downregulation of the PDLP gene in N. benthamiana resulted in delayed symptom appearance up to 7–12 days post inoculation with reduced CMV accumulation compared to the control plants expressing TRV2-eGFP. In contrast, SRC2-silenced plants showed enhanced susceptibility to CMV infection compared to the control plants. Our data suggest that the PDLP gene might facilitate infection of CMV, thus being a susceptibility factor, while the SRC2 gene could play a role in resistance to CMV infection in N. benthamiana.