The production of coronavirus disease 2019 vaccines can be achieved by transient expression of the Spike (S) protein of Severe Acute Respiratory Syndrome Coronavirus 2 in agroinfiltrated leaves of Nicotiana benthamiana, a process promoted by the co-expression of viral silencing suppressor P19. Upon expression, the S protein enters the cell secretory pathway, before being trafficked to the plasma membrane where formation of coronavirus-like particles (CoVLPs) occurs. We recently used RNAseq and time course sampling to characterize molecular responses of N. benthamiana leaf cells expressing P19 only or P19 in combination with recombinant S protein. This revealed expression of the viral proteins to deeply affect the physiological status of plant cells, including through the activation of immune responses. Here, transcriptomics shows that the production of CoVLPs also induces leaf senescence, as revealed by the up-regulation of senescence-associated genes, activation of senescence-related proteases and down-regulation of genes involved in basic metabolic functions like photosynthesis or nitrogen uptake and assimilation. CoVLP production also up-regulates asparagine synthetase genes and leads to the consequent accumulation of asparagine, a nitrogen-rich amino acid known to facilitate reallocation of nitrogen resources from senescent to young growing organs. Hypothesizing these combined host responses to restrain foreign protein accumulation, an attempt was made to support nitrogen reduction in CoVLP-producing leaves by co-expressing a constitutively active, light-insensitive form of nitrate reductase. We show this strategy to increase S protein accumulation in leaf tissues, thereby suggesting that boosting nitrogen metabolism in agroinfiltrated leaves may improve recombinant protein yields in N. benthamiana.

Background Hairy root (HR) transformation assays mediated by Agrobacterium rhizogenes, both in vitro and ex vitro, are essential tools in plant biotechnology and functional genomics. These assays can be significantly influenced by various factors, which ultimately can enhance the efficiency. In this study, we optimized a two-step ex vitro HR transformation method using the actual mother plant combined with the RUBY system and compared with existing methods. Results The two-step ex vitro method proved more efficient than both the one-step ex vitro and in vitro methods, with the highest transformation efficiency of 90% observed in the actual plant. This technique also demonstrated a faster and less complicated approach, reducing time to achieve massive transgenic HR formation by 9–29 days compared to other methods. Conclusions A novel, quicker, less complicated, and more efficient two-step transformation method for cannabis has been established, presenting a significantly lower risk of contamination. This protocol is particularly interesting to produce secondary metabolites using the CRISPR/Cas system in cannabis. We anticipate that this method will facilitate substantial time savings by rapidly producing hundreds of transformed samples.

Efficient and consistent DNA extraction is crucial for genotyping but often hindered by the limitations of traditional manual processes, which are labour-intensive, error-prone, and costly. We introduce a semi-automated, robotic-assisted DNA extraction (RoboCTAB) tailored for large-scale plant genotyping, leveraging advanced yet affordable liquid-handling robotic systems. The protocol/workflow integrates a CTAB extraction protocol specifically adapted for a robotic liquid-handling system, making it compatible with high-throughput genotyping techniques such as SNP genotyping and sequencing. Various plant parts (leaves, roots, manual seed chip) were explored as the source material for DNA extractions, with the aim of identifying the tissue best suited for collection on a large scale. Young roots (radicle) proved the easiest to harvest at scale, while the harvest of leaves and seed chips were more laborious and error-prone. DNA yield and quality from both leaves and roots (but not seed chips) were similar and sufficient for downstream analysis. Interestingly, root tissue could still be extracted from imbibed seeds, even if the seeds failed to germinate, thus proving useful for DNA extraction. Cost analysis indicates significant savings in labour costs, highlighting the approach’s suitability for large-scale projects. Quality assessments demonstrate that the robotic process yields high-quality DNA, maintaining integrity for downstream applications. This semi-automated DNA extraction system represents a scalable, reliable solution for large-scale genotyping that is accessible to many users who cannot implement highly sophisticated and costly systems as are known to exist in large multinational seed companies. RoboCTAB, a low-cost, optimized method for high-throughput DNA extraction, minimizes the risk of cross-contamination. RoboCTAB is capable of processing up to four 96-well plates (384 samples) simultaneously in a single run, improving cost-efficiency and providing seamless integration with laboratory workflows, potentially setting new standards for efficiency and quality in DNA processing and sequencing at scale.

Exploitation of disease resistance genes in soybean (Glycine max (L.) Merr.), as an effective method for management of Phytophthora sojae (Kauf. & Gerd.), is on the verge of an impasse. Few of the known resistance genes are commercially exploited, and even fewer have been precisely identified. Therefore, little is known about the identities or relationships between those genes, a hindrance preventing optimal introgression of new sources of resistance into elite soybean lines. In this study, we have applied state-of-the-art nucleotide-binding and leucine-rich repeat gene capture (RenSeq) using a set of approximately 80,000 unique baits on near-isogenic lines, whole-genome resequencing, and bulked segregant analysis to uncover a resistance gene that has remained elusive for 40 years. This work highlights the reassessment of the Rps3b locus from Chr13 to Chr7 and the description of two alleles, from Turkish and Chinese landraces, of a sole candidate gene. We have identified Rps3b in four, fully resequenced, genetic backgrounds, including the original PI from 1985, in which the resistance gene was originally described. Specificity of the resistant alleles was achieved through phenotypic characterization with field isolates carrying virulent and avirulent forms of the corresponding effector, Avr3b. Surprisingly, these alleles showed extremely high synteny and sequence identity with Rps11 consistent with allelism, and conferred a resistance phenotype indistinguishable from that of the recently cloned Rps11. These results offer new sources of resistance for breeders that are effective against the current P. sojae pathotypes in the field.

Lawns are ubiquitous in North American urban environments and constitute a simplified ecosystem with low plant diversity compared to natural ecosystems. Given their prevalence, these areas have great potential to enhance biodiversity, for example by increasing their attractiveness to pollinators. However, scientific data on the use of alternative groundcovers in established lawns is scarce. The goal of this two-year project was to monitor the attraction of pollinators and resilience of four different groundcover species (Fragaria virginiana Miller, Bellis perennis L., Trifolium repens L., and Thymus serpyllum L.) incorporated into existing lawns in Québec City and Montréal (Canada). A total of nine experimental sites were established in June 2021. A conventionally mowed lawn as well as an unmowed lawn were included as controls at each site. Plant survival, growth, and flowering data were collected at 21-day intervals in 2021 and monthly in 2022. Sweep net sampling was performed to assess pollinator diversity and abundance. Our results showed that all four species can be successfully introduced into established lawns. Fragaria virginiana and T. serpyllum had the highest survival, T. repens and T. serpyllum showed the highest cover, and B. perennis consistently produced the most flowers despite having a lower survival. Established lawns at all sites already had significant floral diversity, which resulted in minimal impact of groundcover introduction on pollinator abundance and diversity. However, a total of 2,389 bees and hover flies were captured, which highlights the positive effects of diversified lawns on pollinators.

Cannabis (Cannabis sativa L.), once sidelined by decades of prohibition, has now gained recognition as a multifaceted and promising plant in both medical research and commercial applications following its recent legalization. This study leverages a genome-wide association study (GWAS) on 174 drug-type Cannabis accessions from the legal Canadian market, focusing on identifying quantitative trait loci (QTL) and candidate genes associated with eleven cannabinoid traits using 282K common single-nucleotide polymorphisms. This approach aims to transform our understanding of Cannabis genetics. We have pinpointed 33 significant markers that significantly influence cannabinoid production, promising to drive the development of Cannabis varieties with specific cannabinoid profiles. Among the notable findings is a massive haplotype of ∼60 Mb on chromosome 7 in Type I (i.e., tetrahydrocannabinol [THC]-dominant) accessions, highlighting a major genetic influence on cannabinoid profiles. These insights offer valuable guidance for Cannabis breeding programs, enabling the use of precise genetic markers to select and refine promising Cannabis varieties. This approach promises to speed up the breeding process, reduce costs significantly compared to traditional methods, and ensure that the resulting Cannabis varieties are optimized for specific medical and recreational needs. This study marks a significant stride toward fully integrating Cannabis into modern agricultural practices and genetic research, paving the way for future innovations.

Background and aims

Benefits for soil health associated with crop rotations can improve plant aboveground biomass, although the effect on root traits is unclear. The aim of this study was to measure the legacy effect of crop rotations typical of dairy farms on root traits of subsequent forage corn (Zea mays L.) and soybean (Glycine max [L.] Merr.). Methods

On a silty clay in eastern Canada, six rotations were compared, varying in crop species (perennials and/or annuals) and fertilizer sources (dairy cattle slurry and/or mineral fertilizer) for 5 years. Roots of subsequent corn and soybean were sampled by coring (0–45 cm), washed, and digitized for image analysis.

Results

Crop rotations including perennial crops rather than only annual crops resulted in greater total net annual productivity in corn (+ 20%) and soybean (+ 21%), corn root biomass (+ 31%) and length density (+ 106%), and proportion of fine roots. Compared to the alfalfa-grass mixture, grass-only mixtures resulted in a greater corn root biomass (+ 23%) and length density (+ 54%). A longer duration (5 vs. 3 years) of the alfalfa-grass mixture improved corn root length density (+ 37%) and corn and soybean fine root proportion at depth, suggesting benefits from maintaining perennial forage stands over time. Mineral fertilizer versus slurry improved root traits of subsequent corn and soybean when applied to perennial but not annual crops.

Conclusion

Our results highlight the positive response of corn and soybean root traits to the presence, species composition, and duration of perennial forage crops, extending further their benefits within rotations.

Field experiments were conducted to determine the establishment and the effectiveness of certain predatory mites in controlling spider mites in raspberry grown under high tunnels. First, the efficacy of Neoseiulus fallacis and N. californicus releases combined with Phytoseiulus persimilis was compared to an acaricide (clofentezine). Weather and low release rates being unfavourable to predator establishment, release strategies were not as effective as the acaricide. Second, the effect of adding an artificial mist on the establishment of P. persimilis was measured. Control was achieved more rapidly by treatment with artificial mist, but the difference in prey and predator density was not significant. Third, a population dynamics model was developed and calibrated with the aim of better understanding spider mite dynamics under tunnel production. The model fits the field data well, is useful for sizing up the impact of different parameters on the population dynamic and shows that temperature is a critical parameter in the management of spider mites.

Phenolic compounds have been proposed to influence decomposition by inhibiting extracellular enzyme activities, as described in the enzymic latch mechanism (ELM). This study examined the effects of phenolic treatments on Sphagnum decomposition, productivity, and biomass accumulation within a Sphagnum farming system. A split-plot experiment with three phenolic treatments was implemented in two cultivation basins established with mosses dominated by the Acutifolia or Sphagnum subgenus. Phenolic treatments were wood pellets (wood), old roots from peat harrowing (root), and no addition (control). Phenolic additions did not result in a measurable reduction in decomposition rates nor was Sphagnum productivity or biomass affected by the experimental treatments. Both subgenera functioned as approximately similar small carbon dioxide (CO2) sinks, with values such as −2 ± 1 g CO2 m−2 d−1 (Acutifolia) and −0.2 ± 0.8 g CO2 m−2 d−1 (Sphagnum). Phenolic additions in both subgenera resulted in higher CO2 values as net ecosystem exchange compared to the control, which could be linked to emissions resulting from wood and root decomposition. In both subgenera, phenolic additions neither increased peat phenolic concentrations nor inhibited enzyme activities compared to the control. The current study did not validate the potential of phenolics in limiting decomposition as theorized in the ELM. The short duration of the experiment may have restricted the effect of phenolic products applied at the surface from reaching the ∼10 cm depth where peat was sampled. This could explain the absence of an inhibitory effect of phenolic products on enzyme activities. Therefore, it is recommended to conduct various sample analyses at different depths to better understand phenolic–enzyme interactions in a Sphagnum farming system.

Background Pharmaceutical safety is an increasing global priority, particularly as the demand for therapeutic compounds rises alongside population growth. Phytocannabinoids, a class of bioactive polyketide molecules derived from plants, have garnered significant attention due to their interaction with the human endocannabinoid system, offering potential benefits for managing a range of symptoms and conditions. Traditional extraction from cannabis plants poses regulatory, environmental, and yield-related challenges. Consequently, microbial biosynthesis has emerged as a promising biotechnological alternative to produce cannabinoids in a controlled, scalable, and sustainable manner. Developing diatom-based biofactories represent a crucial step in advancing this biotechnology, enabling the efficient production of high-valued compounds such as cannabinoids. Results We engineered the diatom Phaeodactylum tricornutum, a unicellular photosynthetic model organism prized for its naturally high lipid content, to produce olivetolic acid (OA), a key metabolic precursor to most cannabinoids. The genes encoding tetraketide synthase and olivetolic acid cyclase from cannabis were cloned onto episomal vectors and introduced using bacterial conjugation in two separate P. tricornutum transconjugant lines to evaluate enzyme activity and OA production in vivo. Both genes were successfully expressed, and the corresponding enzymes accumulated within the transconjugant lines. However, despite testing the cell extracts individually and in combination, OA accumulation was not detected suggesting potential conversion or utilization of OA by endogenous metabolic pathways within the diatoms. To investigate this further, we analyzed the impact of CsTKS expression on the diatom’s metabolome, revealing significant alterations that may indicate metabolic flux redirection or novel pathway interactions. Conclusions Our study demonstrates the successful expression of cannabinoid biosynthetic genes in P. tricornutum but highlights challenges in OA accumulation, likely due to endogenous metabolic interactions. These findings underscore the complexity of metabolic engineering in diatoms and suggest the need for further pathway optimization and metabolic flux analysis to achieve efficient cannabinoid biosynthesis. This research contributes to advancing sustainable biotechnological approaches for cannabinoid production. Graphical abstract

The different steps of alternative splicing (AS) in plants and its regulatory mechanisms have already been studied extensively. Its broader impact on cell identity, plant immunity-related genes, and their study as a whole remains to be investigated. Using transgenic plants, we sorted 11 different Arabidopsis thaliana cell types ranging from root to aerial organs using fluorescence-activated cell sorting. RNA-seq data were analyzed with vast-tools and enabled us to generate a high-resolution AS landscape across multiple cell types, all collected through the same experimental procedure. The analysis of cell type-specific gene expression and alternative splicing events highlights the importance of AS on transcription and AS regulation itself. AS is also shown to be tightly linked to cell identity. By using closely related cell types, we captured alternative splicing events involved in specific stages of plant development. The columella cells, among others, show intensified AS regulation and an interesting splicing profile, especially regarding immunity-related genes. Overall, our analysis brings a valuable tool in the study of cell type identity, plant immunity, and AS.

Advancements in sequencing technologies have dramatically transformed genomics research by enabling the analysis of genetic information with unprecedented scale and efficiency. Next-generation sequencing, renowned for its high-throughput capabilities, has significantly reduced costs and expanded the scope of sequencing applications. Among these, sequencing by synthesis on Illumina systems is predominant, favored for its accuracy and cost-effectiveness. However, emerging technologies like Element Biosciences’ sequencing by Avidity (AVITI) are beginning to challenge this dominance. In this study, we sequenced and genotyped a library of 40 Cannabis samples using both the AVITI and Illumina NovaSeq systems. After filtering out low-quality variants, both technologies showed an 81.2% overlap with 98.9% concordance in genotype calls. AVITI stands out for its flexibility and reduced per-base costs, presenting a viable option particularly for mid-sized laboratories. As the scientific community continues to seek ways to lower genotyping expenses, the combination of the AVITI system with NanoGBS library preparation offers a cost-effective solution adaptable to a wide range of project sizes.

Amaryllidaceae alkaloids (AAs) are diverse bioactive metabolites with significant pharmaceutical potential, derived from 4′-O-methylnorbelladine (4′OM). The biosynthesis of these compounds involves the condensation of tyramine and 3,4-dihydroxybenzaldehyde by norbelladine synthase (NBS) and/or noroxomaritidine/norcraugsodine reductase (NR), followed by O-methylation. Cytochrome P450 enzymes, particularly the CYP96T family, introduce further structural diversity through C–C couplings, resulting in lycorine, galanthamine and crinine cores. Despite their importance, the exact biosynthetic pathways remain poorly defined. In this study, we describe key enzymes from Leucojum aestivum (La), providing crucial insight into AA biosynthesis. Transient expression in Nicotiana benthamiana demonstrated that LaNBS and LaNRII catalyse the conversion of tyramine and 3,4-dihydroxybenzaldehyde to norbelladine, which is subsequently O-methylated by a norbelladine-4′-O-methyltransferase (LaN4′OMT) in planta. Co-agroinfiltration of LaNBS, LaNRII, LaN4′OMT and LaCYP96T1 resulted in the production of various phenol-coupled products, with lycorine as the predominant compound, alongside haemanthamine, crinine/vittatine and norgalanthamine. This study identifies LaCYP96T1 and LaCYP96T2 as the first monocot enzymes capable of catalysing all three regioselective C-C phenol couplings and also highlights the substrate promiscuity of LaNRII. The findings not only elucidate critical steps in AA biosynthesis but also open new avenues for biotechnological application in producing valuable alkaloids, offering potential for novel drug development.

This study examines the conservation of ethylene response mechanisms in cannabis seedlings, expanding on evidence of
ethylene’s influence in mature plants, particularly sexual plasticity. Using hemp and drug-type seedlings, we observed a unique
triple-response-like phenotype under dark conditions with ethephon treatment, characterized by hypocotyl and radicle shortening alongside hypocotyl thickening. Employing a novel ethephon-based assay, this research circumvents the challenges of gaseous ethylene, enabling more accessible investigation of ethylene sensitivity in early development. Results showed high
responsiveness to low ethephon concentrations (125–500 mg/L), unlike prior findings in mature plants, while silver thiosulfate
(1–3 mmol/L) consistently reversed ethylene effects, supporting the conservation of ethylene signaling pathways across genetic
backgrounds. Interestingly, the absence of an exaggerated apical hook in treated seedlings suggests unique regulatory adjustments in achene-bearing plants. This study advances our understanding of ethylene signaling in early cannabis development
and provides a foundation for future research on ethylene’s role in developmental processes, including sexual plasticity.

Triazenes, or amino-substituted diazenes, are organic compounds containing three contiguous nitrogen atoms, that have potent biological activities. We previously demonstrated that triazenes, particularly those substituted with a phenyl or 3-pyridyl ring at the 1-position and a 2-pyridyl ring at the 3-position, exhibit anti-DENV properties. Here, we evaluated the antiviral activity against a betacoronavirus (HCoV-OC43) and a lentivirus (HIV-1). 1-(4-trifluoromethylphenyl)-2-imidazole-1-yldiazene (21) exhibited broad-spectrum activity (EC50 = 6.6–6.8 μM) but was cytotoxic to THP-1 cells. Pyridyl triazenes (14, 15) were the most potent against HCoV-OC43, while 1-(4-methoxyphenyl)-2-morpholin-4-yldiazene (6) and 1-(4-methoxyphenyl)3-(-6-methylpyridin-2-yl)triazene (10) inhibited HIV-1 the most. Structure–activity relationship analysis, supported by molecular docking, indicated that para-methoxy groups favored interactions with viral enzyme binding pockets, enhancing antiviral potency, while meta and para-trifluoromethyl groups were associated with reduced activity and increased cytotoxicity. These findings support the further development of triazenes as antiviral scaffolds.

Plant essential oils (EOs) represent a potentially effective, safe, and eco-friendly alternative to synthetic pesticides that cause negative effects for human health and the environment. While numerous studies have been conducted with EOs from tropical and temperate plants, very few studies have investigated the toxicity of EOs from Nordic plants against plant pathogenic organisms and pests. The present study evaluated in airtight glass chambers the toxicity of vapours produced by EOs obtained from sweet gale, balsam poplar, Labrador tea, jack pine, and black spruce against different pathogenic organisms and pests of cultivated plants. Vapours of Labrador tea EO strongly or completely inhibited the mycelial growth of Alternaria solani, Phytophthora capsici, and Sclerotinia sclerotiorum, while vapours of sweet gale, black spruce, and jack pine EOs inhibited the mycelial growth to a lesser extent. Vapours of all tested EOs were shown to have bactericidal activity against Clavibacter michiganensis subsp. michiganensis, insecticidal activity against bird cherry-oat aphids, acaricidal activity against spider mites, and phytotoxicity against Powell's amaranth. The study reveals the toxicity of EOs from Nordic plants against various pathogens and pests affecting crops, opening new avenues of research for the development of low-risk alternatives to synthetic pesticides in agriculture, with minimal impact on the environment and human health.

Viral diseases are an important threat to crop yield, as they are responsible for losses greater than US$30 billion annually. Thus, understanding the dynamics of virus propagation within plant cells is essential for devising effective control strategies. However, viruses are complex to propagate and quantify. Existing methodologies for viral quantification tend to be expensive and time-consuming. Here, we present a rapid cost-effective approach to quantify viral propagation using an engineered virus expressing a fluorescent reporter. Using a microplate reader, we measured viral protein levels and we validated our findings through comparison by western blot analysis of viral coat protein, the most common approach to quantify viral titer. Our proposed methodology provides a practical and accessible approach to studying virus-host interactions and could contribute to enhancing our understanding of plant virology.

In the Global North, alternative livestock farms are sometimes considered preferable to large-scale specialized farms, which are largely preeminent in current livestock supply chains. In this study, we aimed to determine if alternative livestock farms respected the socioeconomic principles of agroecology. A qualitative thematic analysis and a multivariate quantitative analysis were conducted based on data gathered from a sample of 15 farms over the course of three years. All farms raised multiple species and marketed their products through multiple different outlets, most of them directly to the end consumer, ensuring high economic diversification and connectivity. High levels of work satisfaction were commonplace, as farmers’ values were aligned with their work. Even though their sales prices were much higher than those obtained by large-scale specialized livestock farms, average net incomes and employee wages were low. Most farms operated at a small scale, but farms with higher gross incomes had higher net incomes, suggesting a certain level of economic performance due to economies of scale. Most farm characteristics were found to be in line with locally accepted social values such as gender equity, animal welfare, and providing ingredients for meat-forward diets, which are the local norm. Farmers deplored the fact that they did not have the institutional leverage to take part in territorial and food system governance. While alternative livestock farms cannot readily replace large scale specialized farms in terms of production volume, their socioeconomic characteristics were found to align with the agroecological ideal.

With increasing demand for crops resilient to environmental variability, haskap (Lonicera caerulea) emerges as a promising berry for northern climates due to its rich bioactive content and distinct flavor. Nevertheless, its fragility presents major challenges for maintaining postharvest quality. This study evaluated the effect of storage conditions on haskap quality using two experimental approaches. The first experiment monitored quality attributes (color, firmness, total soluble solids, titratable acidity, weight loss, and antioxidant capacity) at temperatures (0°C, 4°C, and 8°C) over 28 days. Storage at 0°C most effectively preserved antioxidant capacity, with peak levels observed on Day 21 (1.04 ± 0.2 mM TE g−1 D.W), alongside maximal phenolic (37.38 ± 1.59 mg GAE g−1 D.W) and flavonoid (26.99 ± 0.99 mg rutin eq g−1 D.W) content. The second experiment, employing a factorial design, assessed the interactive effects of relative humidity (RH) (90% and 95%), temperature (0°C, 4°C, and 8°C), and time (1, 10, and 20 days) on haskap quality. Optimal conditions for quality preservation were identified as 0°C and 90% RH for 10 days of storage. These findings establish key storage requirements for haskap, informing postharvest practices aimed at maximizing shelf life and bioactive retention.

Galanthamine, an isoquinoline alkaloid used to treat symptoms of Alzheimer's disease, is predominantly extracted from Amaryllidaceae plants, yet its supply remains limited. In this study, we identified, isolated, and characterized N-methyltransferases (NMTs) from three galanthamine-producing species: Leucojum aestivum, Lycoris radiata, and Hippeastrum papilio. The transcriptomic analysis identified five unique NMT isoforms, among which LaLrHpNMT1, an isoform highly conserved across all three species, exhibited the highest catalytic activity. Phylogenetic and structural analyses revealed that these enzymes share high sequence conservation and maintain the class I methyltransferase Rossmann fold with key catalytic residues, paralleling known NMTs from benzylisoquinoline alkaloid pathways. Flexible docking simulations confirmed that norgalanthamine, a crucial precursor, fits within the enzyme's active site and interacts with conserved residues Glu204 and His208. In vitro and in planta assays demonstrated that LaLrHpNMT1 efficiently catalyzes the N-methylation of norgalanthamine to galanthamine. Site-directed mutagenesis confirmed the key role of Glu204 and the participation of Phe residues in substrate stabilization. Additional enzyme assays revealed that LaLrHpNMT1 is promiscuous towards various alkaloid intermediates, while subcellular localization using eGFP-tagged constructs exposed a dual distribution in the cytosol and endoplasmic reticulum, suggesting that NMT activity occurs at the cytosol–ER interface where other biosynthetic enzymes reside. Environmental stress experiments in H. papilio shoots culture showed significant upregulation of NMT expression under heat and other stress conditions associated with AA levels modulation, indicating a potential link between stress responses and alkaloid biosynthesis. These findings deepen our understanding of galanthamine biosynthesis and provide a foundation for metabolic engineering strategies aimed at improving production yields.

Protected crops like greenhouses and indoor farms using light-emitting diodes (LEDs) allow precise control of light spectrum, intensity, and photoperiod for agronomic purposes. These artificial light conditions also influence insects and arachnids, including predators used in biological control. Despite growing interest, the effects of LEDs on predator behavior and control efficacy remain poorly understood. In microcosm experiments, we studied the locomotion and predation behaviors of the generalist predator Orius insidiosus against thrips (Frankliniella occidentalis) under different light spectra and intensities. We tested narrowband blue, green, and red spectra, 3 blue-red ratios, and a spectrum combining all 3 colors across a light-intensity gradient. Predators attacked prey under all lighting conditions, with 70% of individuals showing predatory behavior during observations. Spectral composition significantly influenced behaviors of interest, while light intensity had negligible effects. Narrowband spectra elicited the highest attack probabilities, but the mixed blue-red spectrum with a higher proportion of red light yielded the highest prey capture rates. The spectrum combining all 3 colors showed intermediate prey capture success. In complex environments with cucumber plants and 24-h artificial light sequences, prey capture probabilities followed similar trends to microcosm experiments. However, thrips survival rates remained similar across all lighting treatments. Our findings suggest that while lighting influences O. insidiosus behavior, this predator remains effective under various conditions, providing a foundation for lighting strategies that balance plant productivity with biological control.

In February 2023, potato (Solanum tuberosum L.) plants (cv. Fianna) exhibiting symptoms of aerial stem rot (water-soaked and brown lesions on the stem) were observed in a field in the Guasave Valley, northern Sinaloa, Mexico with an incidence of approximately 40%. Ten symptomatic stem fragments from five diseased plants were disinfected, plated on crystal violet pectate (CVP) medium, and incubated at 28°C for 24 h (Hélias, 2012). Single colonies that formed cavities were selected for further analysis. Five representative isolates, showing biochemical and morphological characteristics consistent with Pectobacterium spp. (Palafox et al., 2024), were chosen. These characteristics included catalase activity, pectinolytic activity, Gram-negative bacilli morphology, absence of oxidase activity, and non-fluorescence on King’s B medium.

The production of coronavirus disease 2019 vaccines can be achieved by transient expression of the spike (S) protein of severe acute respiratory syndrome coronavirus 2 in agroinfiltrated leaves of Nicotiana benthamiana. Relying on bacterial vector Agrobacterium tumefaciens, this process is favoured by co-expression of viral silencing suppressor P19. Upon expression, the S protein enters the cell secretory pathway, before being trafficked to the plasma membrane where formation of coronavirus-like particles (CoVLPs) occurs. We previously characterized the effects of influenza virus hemagglutinin forming VLPs through similar processes. However, leaf samples were only collected after 6 days of expression, and it is unknown whether influenza VLPs (HA-VLPs) and CoVLPs induce similar responses. Here, time course sampling was used to profile responses of N. benthamiana leaf cells expressing P19 only, or P19 and the S protein. The latter triggered early but transient activation of the unfolded protein response and waves of transcription factor genes involved in immunity. Accordingly, defence genes were induced with different expression kinetics, including those promoting lignification, terpene biosynthesis, and oxidative stress. Cross-talk between stress hormone pathways also occurred, including repression of jasmonic acid biosynthesis genes after agroinfiltration, and dampening of salicylic acid responses upon S protein accumulation. Overall, HA-VLP- and CoVLP-induced responses broadly overlapped, suggesting nanoparticle production to have the most effects on plant immunity, regardless of the virus surface proteins expressed. Taking advantage of RNAseq inferences, we finally show the co-expression of Kunitz trypsin inhibitors to reduce CoVLP-induced defence and leaf symptoms, with no adverse effect on plant productivity.

The study investigated the effect of 17 synthetic fungicides used in strawberry fields in Québec (Canada) on the in vitro growth of Hirsutella sp., an entomopathogenic fungus. Isolates collected from cyclamen mites from farms with a conventional growing system (Hirsutella sp. H94 and Hirsutella nodulosa H98) and from a farm with an organic growing system (H. nodulosa H0) were selected for the study. All the fungicides tested strongly inhibited the mycelial growth of the three isolates, although slight differences in sensitivity were observed. Fullback® 125 SC (A.I.: flutriafol), Mettle® 125 ME (A.I.: tetraconazole), NovaTM (A.I.: myclobutanil), and Quadris top® (A.I.: azoxystrobin and difenoconazole) were the most effective at inhibiting the growth of the three isolates. Property® 300SC (A.I.: pyriofenone) was the fungicide with the lowest inhibiting effect on the growth of the three isolates. Isolates H94 and H98 obtained from farms with a conventional growing system, and thus frequently exposed to synthetic fungicides, did not show resistance to the fungicides tested. The study suggests that fungicides might negatively impact the natural populations of the entomopathogenic fungi of the genus Hirsutella on strawberry plants.

Angular leaf spot (ALS) caused by Pseudomonas syringae is an important seedborne bacterial disease in cucurbits. Currently, growers have very few alternatives to copper-based pesticides for the control of the disease in both conventional and organic growing systems. Recent work performed by our group revealed that sugar maple and silver maple leaf extracts show potential as alternatives to the use of copper-based pesticides for the control of plant-pathogenic bacteria. This study investigated the antibacterial and prophylactic activity of ethanolic sugar maple/silver maple autumn-shed leaf extracts against P. syringae. Silver maple and sugar maple leaf extracts showed antibacterial activity under in vitro conditions against P. syringae with minimum inhibitory concentration (MIC) values of 0.39 and 0.78 mg/mL, respectively. The extracts were also very effective as seed treatments at concentrations of 50 or 100 mg/mL. Foliar applications of sugar maple leaf extracts at concentrations of 14.1 mg/mL (corresponding to phytotoxic dose 5% [PD5] value) and 28.2 mg/mL (corresponding to 2 × PD5 value) were either as effective (PD5) or more effective (2 × PD5) than copper octanoate to control ALS on cucumber plants. Silver maple leaf extracts used at a concentration corresponding to PD5 value were as effective as copper octanoate to control ALS on cucumber. Foliar applications of the extracts also showed efficacy in reducing the severity of ALS on butternut squash plants. This study opens new avenues for the management of ALS in cucurbits using silver maple and sugar maple leaf extracts as alternatives to the use of copper-based pesticides.