Jeanmarie Verchot

Rose rosette virus (RRV) causes witches’ broom disease in roses. This study examined whether differences in disease in these spatially distinct domains are associated with local changes in defense-related hormones and transcriptional reprogramming. The levels of defense-related phytohormones salicylic acid (SA), jasmonic acid (JA), 9-lipoxygenase (9-LOX), 13-lipoxygenase (13-LOX), and derived oxylipins were different in these distinct tissues. We curated differentially expressed genes involved in the biosynthesis, storage, and signaling of SA, JA, and oxylipins to reveal how specific defense pathways correlate with these distinct disease states. Gene ontology (GO) analysis and the Disease Resistance Analysis and Gene Orthology 3 (DRAGO3) pipeline revealed stress-associated genes and classical resistance (R) gene families that were differently expressed in these distinct tissue domains. Promoter analysis of defense-associated transcription factors and histone modifiers revealed hormone responsive elements, suggesting complex hormone crosstalk is involved in defense-related gene expression. We confirmed by RT-qPCR, a notable subset of defense genes in the chromosome 5 hotspot, specifically in the linkage group 5 (LG5) quantitative trait loci, linked to reduced RRV susceptibility, was altered in both field-infected and greenhouse-inoculated plants. The association of high versus low disease states with distinct defense hormone signatures and gene expression patterns suggests that local immune states, rather than whole-plant defenses, determine whether a cane becomes rosetted or remains asymptomatic.

Rose Rosette Disease (RRD) has three components (host plant, virus, and vector mite) which interact with each other as well as with the environment. This review will address each component, their i...

Yeast models are widely used to study molecular chaperones from diverse organisms, including plants, because of their well-characterized genetics and the conservation of the protein-folding machinery among eukaryotes. Cross-species complementation studies in yeast have yielded valuable insights into conserved biochemical activity and molecular functions that manage protein folding, assembly, and repair during stress. This study evaluated the functional capacity of three potato StBiP isoforms (StBiP1, StBiP2, and StBiP3) to complement the kar2 deletion (kar2Δ) strain under a range of environmental and ER stress conditions. All three StBiPs partially restored colony growth under normal conditions, demonstrating that they are functional orthologs of yeast KAR2 and can support core ER housekeeping functions. Under severe stress, however, the isoforms diverged: StBiP3 most effectively complemented the kar2Δ strain during heat- and chemically induced ER stress, whereas StBiP1 and StBiP2 provided weaker protection. Unfolded protein response (UPR) activation, monitored via HAC1 mRNA splicing, further highlighted isoform-specific differences in how the StBiPs support IRE1-HAC1 signaling under ER stress and oxidative stress. A conserved cysteine in the nucleotide-binding domain, previously implicated in Kar2 redox control, was also critical for StBiP3-mediated protection in yeast, although the same mutation led to different consequences in plant tissues. Together, these findings provide evidence of subfunctionalization among potato BiP isoforms, with StBiP3 emerging as a stress-specialized chaperone that is a promising target for improving ER stress resilience in solanaceous crops.

Tomato spotted wilt virus (TSWV) is an economically devastating pathogen that rapidly overcomes genetic resistance in major crops. Reverse genetic systems are crucial for investigating plant–virus interactions and resistance-breaking mechanisms, and developing these tools for segmented ambisense RNA viruses remains a crucial challenge. Current TSWV clones rely on extensively modified Asian isolates requiring co-delivery of multiple replication helpers and viral silencing suppressors. Streamlining these systems for regionally significant strains with minimal genetic alterations is essential. Here, we developed the first infectious clone of a U.S. TSWV isolate (PA01). Three binary plasmids contain cDNAs for the antigenomic L and S segments, as well as the genomic M segment, with enhanced GFP replacing NSs on the S segment. Co-delivery of the cucumovirus 2b alone or in combination with tombusvirus P19 or begomovirus AL2 achieved a high proportion of systemically infected Nicotiana benthamiana and Capsicum annuum plants. In N. tabacum, co-delivering the Caenorhabditis elegans cell death suppressor CED-9 or using NahG transgenic plants produced 30 to 33% systemically infected plants. Co-delivery of 2b boosted infection levels in NahG plants to 62%. These data indicate that in addition to the antiviral RNA-silencing machinery, additional host defense pathways influence TSWV rescue and systemic infection from cDNA. [Formula: see text] Copyright © 2026 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Aims: The plant and soil microbiome serve as a reservoir of beneficial endophytic bacteria, including plant-growth-promoting (PGP) Bacillus subtilis, which enhances nutrient acquisition and protects plants against environmental stresses. We isolated novel bacteria from cultivated peanut plants selected from agricultural fields that survived a season of water scarcity and high temperatures. Experiments were conducted to determine whether plant survival was partially attributable to the presence of beneficial microbes that could be harnessed for future biotechnology applications. Methods and Results: Seven bacterial isolates of Bacillus spp. were identified through 16S rRNA sequencing, revealing close affiliations to B. subtilis, B. safensis, and B. velezensis. Growth curve analysis and colony morphology characterization revealed distinct growth patterns across different media types, while phytohormone production assays demonstrated variable indole-3-acetic acid (IAA) synthesis among isolates. When applied as seed biopriming agents to two hybrid peanut varieties, bacterial inoculation significantly enhanced root surface area and root tip development, with B. subtilis-TAM84A showing the most pronounced effects on ‘Schubert’ roots. In addition, vegetative growth assessments indicated increased branch numbers and plant height, particularly with treatments with B. velezensis strains TAM6B and TAM61A, and a consortium of all isolates. Under drought conditions, inoculated plants exhibited delayed wilting and improved recovery after rehydration, indicating enhanced drought resilience. Conclusions: Several local Bacillus strains recovered from drought-tolerant peanut plants showed improved growth and drought tolerance in greenhouse-grown peanut plants. Ongoing field studies aim to evaluate the potential of regionally adapted microbial populations as soil amendments during planting. Impact Statement: This study demonstrates that local strains of Bacillus isolated from drought-resistant peanut plants possess significant potential as bioinoculants to improve growth and drought tolerance in potted peanut plants. This work provides a foundation for utilizing regionally adapted microbial populations to address agricultural challenges related to water scarcity.

Rose rosette virus (RRV) causes disease in rose shrubs manifesting as abnormal branch growth, stem thickening, increased thorniness, as well as malformed, discolored leaves and flowers. The uneven and strange development near apical regions and only in parts of the plant led us to investigate how RRV influences growth promoters to alter internal developmental programs. Leaf samples were collected from symptomatic (rosetted) and asymptomatic shoots of the same rose plants. We quantified viral RNA levels and analyzed the concentrations of some key hormones (abscisic acid [ABA], caffeic acid [CFA], indole acetic acid [IAA], and gibberellin [GA]). Additionally, gene expression profiling was performed, focusing on genes involved in hormone synthesis and signaling, auxin transport, and plant development. Viral RNA levels were unevenly distributed between rosetted and non-rosetted tissues. The ABA and IAA levels were similar between tissue types, whereas CFA and GA exhibited marked differences. We identified 39 genes with distinct or opposite expression in rosetted versus asymptomatic tissues, including PILS3, PIN1, and two SAUR genes related to auxin transport and response. Expression of key regulators of ABA and GA synthesis and signaling, including YUCCA and AUX/IAA genes, were altered. Notably, Lonely Guy 3 (LOG3), which encodes a cytokinin-acitvating enzyme implicated in leaf patterning was significantly reduced in rosetted leaves, suggesting leaf-specific hormone imbalances. Several WOX transcription factors were suppressed indicating a potential role in antiviral responses. Our findings demonstrate that RRV selectively alters hormonal profiles and gene expression involved in plant growth and development. This study identified precise incursions of RRV into host molecular mechanisms controlling plant development and growth.

Background: Virus infection and herbivory can alter the expression of stress-responsive genes in plants. This study employed high-throughput transcriptomic and alternative splicing analysis to understand the separate and combined impacts on host gene expression in Arabidopsis thaliana by Myzus persicae (green peach aphid), and turnip mosaic virus (TuMV). Results: By investigating changes in transcript abundance, the data shows that aphids feeding on virus infected plants intensify the number of differentially expressed stress responsive genes compared to challenge by individual stressors. This study presents evidence that the combination of virus-vector-host interactions induces significant changes in hormone and secondary metabolite biosynthesis, as well as downstream factors involved in feedback loops within hormone signaling pathways. This study also shows that gene expressions are regulated through alternative pre-mRNA splicing and the use of alternative transcription start and termination sites. Conclusions: These combined data suggest that complex genetic changes occur as plants adapt to the combined challenges posed by aphids and the viruses they vector. This study also provides more advanced analyses that could be used in the future to dissect the genetic mechanisms mediating tripartite interactions and inform future breeding programs.

Summary: IRE1, BI‐1, and bZIP60 monitor compatible plant–potexvirus interactions though recognition of the viral TGB3 protein. This study was undertaken to elucidate the roles of three IRE1 isoforms, the bZIP60U and bZIP60S, and BI‐1 roles in genetic reprogramming of cells during potexvirus infection. Experiments were performed using Arabidopsis thaliana knockout lines and Plantago asiatica mosaic virus infectious clone tagged with the green fluorescent protein gene (PlAMV‐GFP). There were more PlAMV‐GFP infection foci in ire1a/b, ire1c, bzip60, and bi‐1 knockout than wild‐type (WT) plants. Cell‐to‐cell movement and systemic RNA levels were greater bzip60 and bi‐1 than in WT plants. Overall, these data indicate an increased susceptibility to virus infection. Transgenic overexpression of AtIRE1b or StbZIP60 in ire1a/b or bzip60 mutant background reduced virus infection foci, while StbZIP60 expression influences virus movement. Transgenic overexpression of StbZIP60 also confers endoplasmic reticulum (ER) stress resistance following tunicamycin treatment. We also show bZIP60U and TGB3 interact at the ER. This is the first demonstration of a potato bZIP transcription factor complementing genetic defects in Arabidopsis. Evidence indicates that the three IRE1 isoforms regulate the initial stages of virus replication and gene expression, while bZIP60 and BI‐1 contribute separately to virus cell‐to‐cell and systemic movement.

Hop latent viroid (HLVd), a subviral pathogen from the family Pospiviroidae, is a major threat to the global cannabis industry and is the causative agent for “dudding disease”. Infected plants can often be asymptomatic for a period of growth and then develop symptoms such as malformed and yellowing leaves, as well as stunted growth. During flowering, HLVd-infected plants show reduced levels of valuable metabolites. This study was undertaken to expand our basic knowledge of HLVd infectivity, transmission, and host range. HLVd-specific primers were used for RT-PCR detection in plant samples and were able to detect HLVd in as little as 5 picograms of total RNA. A survey of hemp samples obtained from a diseased production system proved sole infection of HLVd (72%) with no coexistence of hop stunt viroid. HLVd was infectious through successive passage assays using a crude sap or total RNA extract derived from infected hemp. HLVd was also highly transmissible through hemp seeds at rates of 58 to 80%. Host range assays revealed new hosts for HLVd: tomato, cucumber, chrysanthemum, Nicotiana benthamiana, and Arabidopsis thaliana (Col-0). Sequence analysis of 77 isolates revealed only 3 parsimony-informative sites, while 10 sites were detected among all HLVd isolates available in the GenBank. The phylogenetic relationship among HLVd isolates allowed for inferring two major clades based on the genetic distance. Our findings facilitate further studies on host–viroid interaction and viroid management.