Ziv Spiegelman

The role of reactive oxygen species and calcium signaling in antiviral defense in Arabidopsis https://www.biorxiv.org/content/10.64898/2026.03.03.709233v1

Tomato leaves with late blight caused by Phytophthora infestans

Hello friends of science! I’m migrating over here from X. There, I had 3,000 followers enjoying plant pathology content! Please help me rebuild. I’ll post plant disease photos, management info, science & nature content. Kicking off with some tomato late blight caused by Phytophthora infestans.

Fig. 1 (shortened, full legend in paper): Wild-type (WT) callus exhibits enrichment in the expression of genes involved in diverse developmental pathways. (A) A 6-week-old callus derived from cotyledons exhibits a remarkable capacity for regeneration. Left to right: somatic embryo formation following a short exposure to 2,4-D; root regeneration; and shoot regeneration. (B) Arabidopsis leaves (third and fourth) lack the capacity for direct regeneration. Leaf explants cultured on root-inducing medium first produce callus, from which roots later regenerate (see Supplementary Fig. S1). Leaves cultured on shoot-inducing medium form green callus but do not regenerate shoots. (C–E) Arabidopsis leaves and 6-week-old calli, derived from cotyledons, were subjected to mRNA-seq analysis in three replicates. (C) Scatter plot of differential gene expression between Arabidopsis WT callus and leaves from 3-week-old plants (FDR<0.05).

🧬🌱 RESEARCH 🌱🧬

Plant callus remains proliferative, pluripotent, and regeneration-competent by promoting cell division, activating developmental regulators, and simultaneously repressing differentiation via H3K27me3 – Mandel et al.

🔗 doi.org/10.1093/jxb/...
#PlantScience 🧪

RNA splicing generates a functionally specialized Rep protein isoform in geminiviruses — enabling timely control of the viral cycle. Strikingly, similar strategies might have evolved in DNA viruses infecting different kingdoms: www.biorxiv.org/content/10.6... Spearheaded by @delphinem-p.bsky.social!

Fig. 1.Potential applications of diverse PL technologies in studying PD biology. Various PL technologies have been developed in recent years, offering promising avenues for advancing the study of PD biology. (A) Comprehensive PL assays using known PD-localized proteins as baits to map PD subdomain proteomes. (B) Tissue/cell type-specific PD-localized proteins tagged with TbID to identify PD protein complexes in specific tissues/cell types. (C) Stress-responsive PD-associated proteins tagged with TbID to identify PD protein complexes in response to stresses. (D) Split-TbID to identify proteins at PD-PM and PD-ER contact sites. (E) TransitID to map endogenous protein movement between cells through PD. (F) MS2-based TbID assay to identify RBPs of mobile RNAs.

🧬📍 SPECIAL ISSUE EXPERT VIEW 📍🧬

📄 Implementation of proximity labeling technologies will advance our understanding of plasmodesmata.
✍️ Li & Aung

🔗 doi.org/10.1093/jxb/...
#PlantScience 🧪

Fig. 2 (shortened, full legend in paper): Structurally characterized M. oryzae effectors in complex with the HMA or HMA-like domains of host target proteins and ID-NLRs. Crystal structures of (A) AVR-PikF with the HMA-like domain of OsHIPP19 from rice (7B1I) (Maidment et al., 2021); (B) APikL2A with the HMA-like domain of sHMA25 from foxtail millet (7NLJ) (Bentham et al., 2021); (C) Pwl2 with the HMA domain of OsHIPP43 from rice (8R7D) (Zdrzałek et al., 2024); (D) AVR-PikD with the HMA-like ID of Pikp-1 from rice (5A6W) (Maqbool et al., 2015); (E) AVR-Pia with the HMA-like ID of Pikp-1 (6Q76) (Varden et al., 2019); (F) AVR1-CO39 with the HMA-like ID of RGA5 from rice (5ZNG) (Guo et al., 2018). Complexes are displayed such that the HMA/HMA-like domains are in equivalent orientations. Domains from HPP/HIPP host targets are coloured light green. Domains from ID-NLRs are coloured dark green.

⚙️🦠 REVIEW 🦠⚙️

Turley & Faulkner explore the function of plant heavy metal-associated domain-containing proteins and speculate about their functions at plasmodesmata by drawing from plant–pathogen interaction studies.

🔗 doi.org/10.1093/jxb/...

#PlantScience 🧪 Christine Faulkner

Fig. 1.Conceptual illustration of retention of plasmodesmata (PDs) components paired with plasma membrane (PM) and endoplasmic reticulum (ER) trafficking mechanisms. (A) PM-associated proteins traffic to the bulk PM via the Golgi body and secretory pathway. (B) Ribosomes associated with the rough ER traffic ER-associated proteins to the bulk ER. (C) The specialized composition at PDs indicated with labels and illustrated with colour gradients: the cortical ER (green) and PD–ER (navy blue), and the bulk (light blue) and specialized (purple) cell wall (CW). Magenta outlining conceptualizes the properties of PD-retained proteins clustered to the PD-specific membranes.

🔎 SPECIAL ISSUE VIEWPOINT 🔎

A variety of motifs mediate protein localization at plasmodesmata. Should they be viewed as targeting or retention signals?

Barr & Tilsner explore the motifs and mechanisms underlying plasmodesmal protein localization ⚙️

🔗 doi.org/10.1093/jxb/...
#PlantScience 🧪

Iranians are experiencing a collective trauma. Thousands have been killed/injured in recent events, the economy is crippled & the threat of a wider conflict is real. This is especially difficult for those living in Iran, as many have lost (or fear losing) loved ones. www.nature.com/articles/d41...

Fig. 1.Dynamic regulation and role of plasmodesmata (PD) in viral RNA and siRNA movement. PD regulate the symplasmic transport of molecules between cells. Viruses encode movement proteins (MPs) that are expressed in cells at the viral infection front to facilitate viral movement through PD. Tobamovirus MPs interfere with pattern-triggered immunity (PTI), a defense mechanism activated by plant receptors that recognize viral double-stranded RNA (dsRNA) and cause PD closure by callose deposition. The open state of the PD at the viral infection front, which allows the virus to spread, also allows the movement of signaling molecules, including viral and host-derived small interfering RNAs (siRNAs). As they move ahead of the infection, these siRNAs play a critical role in systemic defense signaling and the regulation of disease outcomes. MIR, miRNA-encoding gene; PTGS, post-transcriptional gene silencing; TGS, transcriptional gene silencing.

🧬🦠 REVIEW 🧬🦠

In this review, Elvira-González et al. describe how virus-induced small RNA synthesis and small RNA movement through plasmodesmata and phloem determine the outcome of viral infection in terms of disease and tolerance.

🔗 doi.org/10.1093/jxb/...
#PlantScience 🧪

A highly potent and broadly accessible bispecific nanobody for the treatment of ebola virus infections Author summary Ebola virus (EBOV) remains a significant global health threat, with current treatments providing only modest survival benefits and limited accessibility due to their dependence on injec...

A highly potent and broadly accessible bispecific nanobody for the treatment of ebola virus infections

journals.plos.org/plospathogen...

Arabidopsis Membrane Contact Site protein SYNAPTOTAGMIN A maintains sieve element endomembrane morphology and function https://www.biorxiv.org/content/10.64898/2026.01.26.701828v1

It was great visiting @mpi-mp-potsdam.bsky.social
Thank you so much ☺️ @incavirus.bsky.social @fritz-kragler.bsky.social

Ziv Spiegelmann (left) and Marco Incarbone (right) standing outside near an office building in snowy weather. They are both smiling in the camera.

Thanks a lot to @zivirus.bsky.social visiting us from @volcaniinstitute.bsky.social to talk about the #tobamovirus revealing a crossroad between viral movement and #PlantImmunity 🍅🦠

Thanks as well to @incavirus.bsky.social for hosting! 🙏

The cover of Vol 77 | Issue 3 | 2026 of the Journal of Experimental Botany, Special Issue: Plasmodesmata: Current perspectives on plant intercellular communication and signalling. Teal coloured banners border the top and bottom of the page and in the centre is an image of multicoloured Nicotiana benthamiana cells under a microscope. Fluorescent proteins (mTurquoise2, mEGFP, mCitrine, mScarlet-I) move between cells via plasmodesmata in the epidermis of N. benthamiana. (Image credit: Rory Greenhalgh, Jacob O. Brunkard.)

📣 Check out JXB's newest Special Issue 📣
📜 Issue 3 of 2026 📜

🔬 Plasmodesmata: Current perspectives on plant intercellular communication and signalling 🔬

📘 Guest edited by Jake Brunkard & Tessa Burch-Smith

🔗 academic.oup.com/jxb...

#JXBspecialissues #PlantScience 🧪 SEBiology

The (Yoav) Voichek lab has opened its gates at the Weizmann Institute, and is actively recruiting students and researchers at all levels - come explore gene regulation and computational genomics in a fun, friendly sprouting lab 🤗🥼⚗️🧪
www.weizmann.ac.il/plants/voichek

An in planta single-cell screen to accelerate functional genetics Genetic screens in whole plants are a powerful tool for functional genetics. However, elucidating gene function in highly redundant genetic programs such as signaling pathways remains challenging in b...

An in planta single-cell screen to accelerate functional genetics--very cool application of the TMV vector pTRBO by Elizabeth Sattely’s Lab 😎
www.biorxiv.org/content/10.1...

Umbravirus-like RNA viruses are capable of independent systemic plant infection in the absence of encoded movement proteins The spread of viral genomes into adjacent cells and the plant vascular system is enabled by viral movement proteins. This study shows that umbravirus-like RNA viruses can spread systemically without e...

#RNASky Hi RNA people! As I look back on 2025 (and not fondly), I’d like to know what you think were the most exciting #RNA papers published and why. Here’s one of mine- we showed for first time that some plant viruses have evolved to use host movement proteins

journals.plos.org/plosbiology/...

bioRxiv: Structural basis for heat tolerance in plant NLR immune receptors (2025) Nucleotide-binding leucine-rich repeat (NLR) immune receptors sense pathogen molecules and oligomerize, initiating defense signaling. Some NLRs function poorly at elevated temperatures for unknown reasons. We show that temperature-sensitive NLRs retain ligand binding at elevated temperatures but are impaired in oligomerization. We identify key residues involved in temperature resilience. Structural modeling reveals stabilizing intramolecular interactions of the NB-ARC domain with surface residues of the adjacent leucine-rich repeat (LRR) that preserve receptor integrity and functionality under heat stress. These insights enable in silico classification of NLRs as temperature-sensitive or -tolerant and underpin design of temperature tolerant variants of temperature sensitive NLRs. These findings provide a mechanistic basis for temperature sensitivity in plant immune receptors and enable engineering of temperature-tolerant disease resistance in crops.

New Preprint: Structural basis for heat tolerance in plant NLR immune receptors (2025)
https://www.tsl.ac.uk/publications/161552

Engineering compact Physalis peruviana (goldenberry) to promote its potential as a global crop Goldenberry (Physalis peruviana) produces sweet, nutritionally rich berries, yet like many minor crops, is cultivated in limited geographical regions and has not been a focus of breeding programs for...

Genome editing of goldenberry ERECTA for crop ideotype. Congrats, Zach Lippman, Joyce Van Eck & the team! "Engineering compact Physalis peruviana to promote its potential as a global crop". ERECTA rock😉
nph.onlinelibrary.wiley.com/doi/10.1002/...

Our work now on @jxbotany.bsky.social. Make sure you add some Cas13a fluorescent virus detection to your Christmas lights ✨️

The Clavel Group is recruiting a new postdoc for two possible projects dealing with plant-virus interactions and selective autophagy! More (wordy) details below ⬇️🌱🦠

Fig. 5 (shortened, full legend in paper): Development of a simplified approach for on-site Cas13a-based diagnostics. (A) Cas13a-mediated detection of tomato brown rugose fruit virus (ToBRFV) in serial dilutions of crude RNA samples from ToBRFV-infected plants diluted in RNA from healthy plants. Viral RNA can be detected in a 1:5 dilution using this method. (B) Equipment required for on-site diagnostics includes dry bath, vortex, portable fluorescence viewer, a pipette, and test tubes. (C) Schematic illustration of virus detection using a portable fluorescence viewer and a cellular phone camera. (D) Mobile phone camera image of serial dilutions of crude RNA from ToBRFV-infected plants. (E) Samples are converted to grayscale. (F) Fluorescence intensity is quantified using ImageJ.

🧬 TECHNICAL INNOVATION 🧬

CRISPR/Cas technology is an emerging tool for identifying nucleic acid sequences.

Hak et al. present a user-friendly, extraction-free, rapid protocol for specific on-site detection of plant viruses using CRISPR/Cas13a.

🔗 doi.org/10.1093/jxb/...
#PlantScience 🧪

The cover of Vol 76 | Issue 21 | 2025 of the Journal of Experimental Botany, Special Issue: Tomato. Purple banners border the top and bottom of the page and in the centre is an image of a ripe tomato fruit on its truss (credit: Marine Honoré).

📣 Check out the Journal of Experimental Botany's newest special issue 📣

🍅 Tomato - Issue 21 of 2025 🍅
📘 Guest edited by Yves Gibon, Diane Beckles, Sonia Osorio & Hiroshi Ezura

🔗 academic.oup.com/jxb...

#JXBspecialissues #PlantScience 🧪 @sebiology.bsky.social @dianemariabeckles.bsky.social

Amazing work by @incavirus.bsky.social and @gesahoffmann.bsky.social on how plants restrict virus transmission to their progeny

🍅 #TomatoTuesday on Monday and I am here for all the 🍅 #PlantScience! 🍅

Rational design of induced regeneration via somatic embryogenesis in the absence of exogenous phytohormones Stem cell transcription factors synergistically induce regeneration involving somatic embryogenesis and can break recalcitrance in Arabidopsis and pepper w

Rational design of induced regeneration via somatic embryogenesis in the absence of exogenous phytohormones (Jana Wittmer, Menno Pijnenburg, Tristan Wijsman, Sieme Pelzer, et al) doi.org/10.1093/plce... #PlantScience @aspbofficial

Florigen activation complex forms via multifaceted assembly in Arabidopsis - Nature In flowering plants, DNA–FD–14-3-3 recruits FT to the florigen activation complex both through DNA–FT interactions and by reducing liquid phase condensation of FD protein, which promotes dimerization,...

Florigen activation complex forms via multifaceted assembly in Arabidopsis

www.nature.com/articles/s41...

Bioluminescent sentinel plants enable autonomous diagnostics of viral infections Plants engineered with synthetic genetic programs can transform how we monitor and manage the extension of crop pests and diseases. Here, we establish a bioluminescent platform in Nicotiana benthamian...

Such a cool pre-print on making sentinel plants - so much potential!

Bioluminescent sentinel plants enable autonomous diagnostics of viral infections

www.biorxiv.org/content/10.1...

Robust branch patterning in moss shoots via symplasmic auxin diffusion Abitbol-Spangaro et al. show that a diffusion-based model of auxin movement accounts for shoot branching patterns in a moss. The model predicts branch distribution changes caused by altered callose-dependent cell-to-cell permeability and reveals how shoot geometry and phyllotaxis drive robust branch spacing as an emergent property of auxin diffusion.

Robust branch patterning in moss shoots via symplasmic auxin diffusion CurrentBiology

a man in a suit and tie is standing in front of a blackboard with the words " anyone ? anyone ? " ALT: a man in a suit and tie is standing in front of a blackboard with the words " anyone ? anyone ? "

This semester, for our Plant & Micro Biosci Grad program, I'm developing a new course on ✨Peer Review✨ & critical thinking. Final project is a full review of a preprint!

I'd love to have a journal editor zoom with the class to share their perspective and do a Q&A.
Anyone interested?

Pls share!