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Frontiers in Plant Science

Frontiers Media SA

Preprints posted in the last 90 days, ranked by how well they match Frontiers in Plant Science's content profile, based on 256 papers previously published here. The average preprint has a 0.24% match score for this journal, so anything above that is already an above-average fit.

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Generation of lachrymatory factor synthase-suppressed onion (Allium cepa L.) by Agrobacterium-mediated gene transfer for CRISPR/Cas9 genome editing

Tamaru, S.; Imai, S.; Watanabe, S.; Ikegai, T.; Kondo, S.; Igawa, T.; Kamoi, T.

2026-07-22 plant biology 10.64898/2026.07.21.739049 medRxiv
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Lachrymatory factor, an irritating volatile with tear-inducing property, is produced when onion bulbs are cut or chopped. We aimed to generate onion plants with reduced lachrymatory factor synthase (LFS) activity via clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR associated protein 9 (CRISPR/Cas9) genome editing. Calli induced from primary roots were transformed with Agrobacterium tumefaciens carrying expression cassettes for CRISPR/Cas9, guide RNA, green fluorescent protein (GFP), and hygromycin resistance; callus lines that showed a high-frequency stable GFP expression were selected as "elite callus lines" that were suitable for transformation. Cleaved amplified polymorphic sequence (CAPS), heteroduplex mobility assay (HMA), and Sanger sequencing confirmed mutations introduced into the LFS gene, and plants were regenerated from the confirmed LFS-edited callus lines. The LFS enzyme activity in the leaves and bulbs of the LFS-edited plants was lower than that in control plants, while the LFS-edited plants exhibited severe growth abnormalities and failed to set seed, possibly due to long-term culture to maintain the elite callus line. The present study first demonstrated that onion genome editing, which modified a specific trait of onion, the reduction of LFS activity, was achieved. The results obtained opened the feasible way toward the final goal: the production of tear-free, higher health-functional onions.

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Proteomic and Metabolomic Profiling of Transgenic Pod Borer-Resistant Cowpea: Assessing Unintended Molecular Changes and Their Implications for Ecosystem Resilience

Isah, A.;Yoila, M.;Ndana, R.;Ibrahim, A.;Ogunremi, O.

2026-06-25 Plant Biology 10.64898/2026.06.24.734197 medRxiv
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BackgroundThe commercialization of Nigerias single-line pod borer-resistant (PBR) cowpea (IT97KT), the first transgenic cowpea variety in the world expressing Cry1Ab gene, has raised questions about potential unintended molecular changes and their ecological implications. This study employed integrated proteomic and metabolomic profiling to compare the transgenic line with its non-transgenic isoline (IT97KN) and assess molecular indicators associated with ecosystem resilience. MethodsProteomic analyses were conducted using LC-MS/MS following filter-assisted sample preparation, while metabolomic profiling employed GC-MS and UHPLC-MS/MS platforms. Differential protein and metabolite abundance were assessed using label-free quantification, volcano plot analysis, principal component analysis (PCA), hierarchical clustering, and Gene Ontology (GO) enrichment analyses. ResultsProteomic profiling revealed substantial overlap between IT97KT and IT97KN, with only a limited subset of proteins exhibiting significant differential abundance. Upregulated proteins in IT97KT were primarily associated with seed storage, redox regulation, oxidative stress mitigation, and defense-related functions, including Late Embryogenesis Abundant Protein 1 (LEA1), vicilins, thioredoxin, and iron superoxide dismutase. Among 37 proteins linked to ecological adaptation, only LEA1, CPRD22, and Bg7S showed significant differences. Similarly, only carbonic anhydrase II displayed differential abundance among proteins associated with potential ecological risk. PCA and clustering analyses demonstrated high proteomic similarity between genotypes. Metabolomic analyses identified sixteen major metabolites, predominantly fatty acids, with no statistically significant differences in abundance or composition between transgenic and non-transgenic lines ConclusionsThe transgenic PBR cowpea exhibited minimal unintended proteomic and metabolomic alterations relative to its non-transgenic isoline. These findings indicate that Cry1Ab insertion did not substantially disrupt molecular pathways associated with ecological adaptation, environmental risk, or metabolic homeostasis, providing molecular evidence supporting the environmental and biosafety equivalence of PBR cowpea.

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Untargeted metabolic analysis reveals intraspecific and organ-specificchemodiversity in Solanum dulcamara

Mendoza-Servin, J. V.; Moreno-Pedraza, A.; Pires Bueno, P. C.; van Dam, N. M.

2026-07-30 plant biology 10.64898/2026.07.29.741464 medRxiv
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Background and AimsThe genus Solanum including the wild species S. dulcamara, is rich in specialized metabolites such as steroidal glycoalkaloids (SGAs). Yet, much of this chemical diversity remains poorly characterized. This study aims to provide a comprehensive assessment of intra-specific chemodiversity in S. dulcamara. Using a dataset generated from 42 globally distributed accessions, we tested whether metabolic profiles differ among plant organs. We postulated that metabolic richness and abundance vary across accessions. Additionally, we hypothesized that differences in geographic origin or altitude affect SGA chemodiversity. MethodsAn untargeted metabolomic approach was applied to leaf, flower and root samples of 42 S. dulcamara accessions. Plants were grown in the greenhouse, and the extracted metabolites were analyzed using UHPLC-HRMS/MS in positive and negative ionization modes. Data processing and metabolite annotation were performed with a tailored bioinformatics workflow. Multivariate analyses were performed to evaluate chemical variation across organs and accessions. Key ResultsOur analyses revealed both organ and accession-specific metabolic diversity. Principal component analysis and clustering analyses revealed metabolic differentiation between leaves, flowers and roots. Leaves showed the highest metabolite richness and abundance, while roots showed the lowest. Alkaloids, especially SGAs, dominated positive mode profiles in roots, whereas shikimates and phenylpropanoids were prominent in negative mode profiles. Based on the leaf and flower SGAs profiles, four chemotypes were identified. Analyses of flavonoid and cinnamic acid derivatives, however, did not reveal chemotypes. Feature-based molecular network analyses confirmed that metabolite clusters are associated with plant organs, but not with altitude or geographic origin of the accessions. ConclusionsThe intraspecific chemodiversity within S. dulcamara is mainly driven by organ and accession-specific metabolic differences. We identified four SGA leaf and flower chemotypes, suggesting possible functional and ecological roles of this aboveground chemodiversity. These insights may contribute to applied research in plant resistance breeding and crop production.

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LsBADH1 is responsible for sweet fragrance in lettuce (Lactuca sativa L.) through 2-acetyl-1-pyrroline biosynthesis

SEKI, K.; Matsui, K.; YANAGIDATE, M.; NISHIDA, K.; KOYAMA, R.; Uno, Y.

2026-06-16 genetics 10.64898/2026.06.13.731611 medRxiv
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HighlightThe sweet fragrance of lettuce was attributed, for the first time, to the synthesis of 2-acetyl-1-pyrroline caused by a deficiency in the betaine aldehyde dehydrogenase gene. Fragrance is among the most valuable traits of high-quality crops and influences consumer preferences. Although 2-acetyl-1-pyrroline (2AP) is a key component of fragrant cultivars in several crops, its genetic mechanism in lettuce (Lactuca sativa L.) remains poorly understood. The betaine aldehyde dehydrogenase (BADH) gene has been identified as causative for 2AP-derived fragrance in rice and soybean cultivars. Hence, we conducted a linkage analysis using an F2 population derived from a cross between Kukichisya (fragrant) and Rennet (non-fragrant) for three candidate genes of BADH orthologs in the lettuce genome. Analysis linked LOC111877932 located in LG4 to the fragrance trait, and it was designated LsBADH1. Comparison among Kukichisya, Salinas, and candidate BADH of sunflower (Helianthus annuus L.) revealed three non-synonymous single-nucleotide polymorphisms (nsSNPs) in exons 1, 2, and 9, and suggested that nsSNP in exon 9 was strongly correlated with fragrance in Kukichisya. A premature stop codon introduced in exon 5 of LsBADH1 using Target-AID base-editing technology resulted in truncated BADH1 and higher 2AP levels. Our results indicated that LsBADH1 is responsible for the 2AP-derived fragrance. Our findings can be applied to select cultivars based on a novel concept for the cooking process, providing a transformative platform to breed fragrant lettuce as a high-value-added product.

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Pyramiding four genes governing bacterial blight resistance in three popular rice varieties of East Africa and Madagascar

Arra, Y.;Loo, E.;Blasco, C.;Thomas, E.;Devanna, B.;Stiebner, M.;Hutin, M.;Auguy, F.;Szurek, B.;Frommer, W.

2026-06-29 Plant Biology 10.64898/2026.06.29.735165 medRxiv
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Bacterial blight of rice causes substantial crop losses in Asia and Africa. The recent introduction of Asian strains into African countries has led to two independent outbreaks detected in 2019, causing severe damage in Madagascar and Tanzania. The strains are highly virulent on local rice varieties and rapidly spread from Tanzania to neighboring countries. Multiplex genome editing of effector-binding elements in the promoter of SWEET rice promoters has successfully generated elite rice lines with broad-spectrum resistance against bacterial blight. While genome-edited crops can be released in countries with biosafety regulations, their use in countries that have yet to establish regulations, e.g., Tanzania and Madagascar, is hindered. To circumvent this, marker-assisted backcross breeding (MABB) of the African elite varieties Komboka, FARO-44, and NE-RICA-4 was adopted to introgress resistance genes to confer resistance to Xoo strains identified in Tanzania (iTz) and Madagascar (iMg). Resistance gene pyramiding, namely Xa1, Xa4, xa13, and Xa21, in the three elite rice varieties conferred resistance to iTz and iMg strains. Our study presents a solution to provide rice breeders in East Africa with bacterial blight resistance in three local rice varieties for field trials, line registration, and deployment.

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Immunoengineered Chitosanase-Produced Chitosan Oligomers for Elevating Plant Resistance to Viral Infection

Khanahmadi, S.; Singh, R.; Ryll, J.; Nava Cruz, N. Y.; Cord-Landwehr, S.; Richter, C.; Rafieerad, A.; Moerschbacher, B. M.

2026-06-10 plant biology 10.64898/2026.06.09.731087 medRxiv
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Chitooligomers can act as plant biostimulants or biopesticides, but todays chitosan-based agro-biologics often lack sufficient efficacy. This is due to a lack of scalable production processes for structurally well-controlled chitosans combined with a limited understanding of structure-function relationships. Chitosans differ in their degree of polymerization (DP), fraction and pattern of acetylation (FA and PA). While the influence of DP and FA on antimicrobial and phytostimulatory properties is at least partially known, this is not yet the case for PA. PA can be partially controlled by using enzymatic rather than acid hydrolysis for oligomer production. We have used recombinant chitinases and chitosanases to hydrolyse a well-characterised chitosan polymer, and purified oligomers with different DP. We have structurally characterised the products and tested their abilities to protect tobacco from viral disease. Chitinase products were dominated by GlcNAc units at their reducing and non-reducing ends, with GlcN units dominating their centers, and v.v. for chitosanase products. While the chitinase-derived hydrolysates were inactive, the chitosanase-derived oligomers possessed elicitor and priming activities and protected plants from disease, and their activity increased with increasing DP. Clearly, the Bacillus chitosanase used is well-suited to set up a scalable production process for chitosan oligomers with promising agro-biologic properties. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=95 SRC="FIGDIR/small/731087v1_ufig1.gif" ALT="Figure 1"> View larger version (56K): org.highwire.dtl.DTLVardef@c312e9org.highwire.dtl.DTLVardef@10eaf99org.highwire.dtl.DTLVardef@12a937corg.highwire.dtl.DTLVardef@38dc8c_HPS_FORMAT_FIGEXP M_FIG C_FIG

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Transcriptomic analysis reveals SnTox8-mediated reprogramming of wheat defence signalling

Padukka Vidanalage, A. A.; Gagalova, K. K.; Furuki, E.; Kamphuis, F.; Rybak, K.; Periyannan, S.; Gibberd, M.; Phan, H. T. T.

2026-07-09 molecular biology 10.64898/2026.07.02.736222 medRxiv
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Parastagonospora nodorum (Berk.) Quaedvlieg, Verkley & Crousis, a necrotrophic fungal pathogen, is the causal agent for septoria nodorum blotch, a major constraint on global wheat production. Pathogen-produced necrotrophic effectors (NEs) that interact with host-sensitivity genes in an inverse gene-for-gene manner, collectively leading to effector-triggered susceptibility (ETS). Here, we investigated the transcriptional responses of two Triticum aestivum L. genotypes, Mace and Lancer, following infiltration with a novel NE, SnTox8. A total of 12,679 unique differentially expressed genes in Mace and 149 in Lancer were detected from transcriptomic analysis. In the SnTox8-sensitive cultivar, Mace, numerous defence-related genes were induced, including protein phosphorylation cascades, reactive oxygen species bursts, calcium signalling, phytohormone modulation, and suppression of photosynthesis, consistent with findings from other ETS models, in which necrotrophic fungal pathogens hijack host defence systems to proliferate. The interaction also activated genes involved in signal transduction, metabolism, membrane modification, and molecular transport, reflecting a coordinated host reprogramming that promotes cellular dysfunction and cell death, thereby facilitating necrotrophic pathogenesis. In contrast, Lancer, an SnTox8-insensitive cultivar, exhibited minimal transcriptional changes with no evidence of effector recognition or downstream defence-related activities. Overall, this study exhibited that SnTox8 manipulates kinase-mediated immune signalling and metabolic reprogramming to convert defence activation into host cell death, revealing a mechanistic basis for ETS in wheat. The identified SnTox8-Snn8-triggered processes were confirmed through additional transcriptome analysis of Mace mutants. Outcomes from this study establish a foundation for identifying, functionally characterising and validating the corresponding host susceptibility gene Snn8.

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Identification and functional analysis of αKNL2 genes in cowpea

Kochevenko, A.; Amasende-Morales, I.; Leon-Martinez, G.; Lua, J.; Ruiz-Maciel, O.; Fuchs, J.; Vielle-Calzada, J.-P.; Houben, A.

2026-07-30 genetics 10.64898/2026.07.27.740913 medRxiv
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Although the KINETOCHORE NULL2 (KNL2) protein is an essential inner centromeri c protein that is crucially important for assembly and functioning of kinetochores, our understanding of its organization, dynamics and function of distinct isoforms in the cells of plant species undergoing mitosis/meiosis is far from complete. In this study, we identified and characterized two KNL2.1/KNL2.2 genes in cowpea. GUS reporter constructs and qRT-PCR revealed that the expression profiles of both genes were variable across organs, with the highest expression in leaves and roots. Using an EYFP gene fusion coupled with immunostaining, it was demonstrated that both KNL2 variants colocalized at centromeres in a cell-cycle-dependent manner. The CRISPR/Cas9 technique was used to generate various in-frame deletion and out-of-frame knock-out knl2 mutants. Single- and double-gene knock-out mutants were generated, and the effects of mutations on plant development and seed setting were analyzed. The results are discussed both with respect to the roles of these proteins in kinetochore assembly and in the context of using KNL2 genes for in vivo production of haploids in cowpea. Significance statementThis study identifies two paralogous KNL2 genes in cowpea and reveals their functional redundancy during centromere assembly and essential role in seed development. These findings expand our knowledge of kinetochore dynamics and provide a basis for exploring the evolutionary diversification of centromeric proteins in legumes.

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Chromosome-Specific Expansion and Diversification of the Thionin Gene Family in Barley

Fu, Y.;Russell, J.;Schreiber, M.;Bos, J.

2026-06-22 Plant Biology 10.64898/2026.06.19.733385 medRxiv
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Thionins are cysteine-rich peptides involved in plant defense. However, their genomic organization, evolutionary expansion, and potential function in barley remain unclear. Here, we integrated reference genome, pan-genome, and pan-transcriptome resources to systematically characterize the thionin gene family in barley. Fifty-six thionin genes were identified in the reference genome Morex V3, displaying pronounced chromosomal clustering and high sequence conservation consistent with extensive tandem duplication. Promoter analysis of these genes revealed enrichment of cis-acting elements associated with stress- and hormone-related signaling pathways, suggesting a potential role for thionins in biotic stress responses, including aphid defense, as suggested by previous studies. Analysis of 20 barley genotypes revealed substantial copy number variation, particularly on chromosomes 6H and 7H, indicating dynamic population-level expansion. Sequence-based clustering grouped thionins into ten clusters and five singletons, with major clusters corresponding to specific chromosomes. Integration of pan-transcriptome data showed that transcriptional activity was largely confined to four major clusters. Aphid infestation of four genotypes featuring copy number variation in chr 6H thionin genes resulted in a strong induction of thionin gene expression, with more pronounced responses during poor-host interactions. Aphid-induced expression tended to increase with thionin gene number, however, this no correlation was observed regarding basal gene expression levels. Together, these findings indicate that the thionin gene family in barley has undergone species-specific expansion driven by tandem duplication and contributes to genotype-dependent aphid defense responses.

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Introducing PHJ Media: A Unique Machine Learning -Driven Basal Formulation to Overcome Recalcitrance for Multi-Genotype Micropropagation of Cannabis sativa L.

Pepe, M.; Hesami, M.; Jones, M.

2026-07-15 plant biology 10.64898/2026.07.14.738465 medRxiv
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Applications of tissue culture are critical for Cannabis sativa L. (cannabis), supporting clonal propagation, germplasm preservation, pathogen elimination, among other biotechnological applications. However, extensive genetic diversity associated with cannabis results in highly variable responses to in vitro conditioning, and no consensus basal media formulation exists to support reproducible micropropagation across genotypes. To address these limitations, a hybridized ensemble-NSGA-II approach was employed for concurrent optimization of individual media components to create a species specific, cultivar inclusive basal salt formulation for cannabis micropropagation. The resulting PHJ media represents a unique formulation that overcomes recalcitrance across a wide array of cannabis cultivars, facilitating improved growth and uniformity for the nine cultivars used in its development and validation. These results remain consistent from explant initiation through multiple rounds of subculture. The ability of PHJ to overcome genotypic recalcitrance is telling of its potential applicability with an array of plant species beyond cannabis. Additionally, robust performance both with and without plant growth regulators underscores the plausible use of PHJ for diverse applications beyond standard micropropagation. Ultimately, this cultivar-inclusive basal medium demonstrates utility for both scientific research and industrial-scale operations.

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Sunrise and sunset times are the main factors that determine the flowering time of photoperiod-sensitive sorghum

Clerget, B.; Sidibe, M.; vom Brocke, K.; Raharinivo, V.; Ortiz, D.; Trouche, G.

2026-07-08 plant biology 10.64898/2026.06.12.731875 medRxiv
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Crop photoperiodism models assume that flowering time is primarily controlled by daylength, yet many field observations contradict this view. We previously proposed an alternative framework integrating daily changes in sunrise and sunset times (dSR and dSS). Variety trials in Madagascar and in Argentina supported this concept: mid-late sorghum varieties from the northern hemisphere flowered late or very late when sown in November and December, consistent with the higher dSR/dSS values of the southern hemisphere summer. One Malian variety, sown monthly over six years in West Africa, exhibited high interannual variability in flowering time when sown between November and February. This revealed that up to four photoperiodic responses -- two quantitative and two qualitative, occurring at different times of the year -- may coexist within a single late photoperiod sensitive variety. All responses use only dSR and dSS cues. The qualitative responses are triggered by an internal phasic coincidence, which is set by a linear relationship between dSR and dSS at the onset of plant photoperiod sensitivity, and between dSR+dSS at panicle initiation. The research model fitted data from 28 varieties grown in Mali well. It also accurately fitted the duration to PI observed in three varieties sown at tropical and temperate latitudes. HighlightThe seasonal photoperiodic adaptation of flowering time in sorghum plants may rely on several signal transduction pathways regulated by sunrise and sunset times rather than day length.

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Development and application of SNP markers to facilitate DUS testing in tomato

Causse, M.;Bitton, F.;Rampant, P.;Duboscq, R.;Berard, A.;Jouy, C.;Delogu, C.;Teunissen, H.;Collonier, C.;Clainche, I.;Hinsinger, D.

2026-06-16 Plant Biology 10.64898/2026.06.16.732596 medRxiv
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Variety registration in Europe requires the evaluation of Distinction, Uniformity, and Stability (DUS) based on multi-environment trials and extensive phenotyping. The integration of molecular markers into DUS testing offers opportunities to increase efficiency and reduce costs, particularly in tomato (Solanum lycopersicum L.), a species characterized by rapid varietal turnover. We developed a high-density SNP genotyping resource targeting gene-rich regions across the tomato genome and applied it to a panel of 300 varieties registered over the past five decades. Temporal patterns of genetic diversity were assessed and compared with those observed in a collection of heirloom accessions predating 1970. Genome-wide association studies (GWAS) were conducted for 50 DUS traits to identify marker-trait associations and evaluate the potential of SNPs to complement phenotypic descriptors. Detected associations were compared with previously reported genes and quantitative trait loci (QTLs), enabling the validation of known loci and the identification of novel candidate genomic regions underlying trait variation. Finally, we assessed the discriminatory power of selected subsets of informative SNPs for variety distinction and grouping. Our results demonstrate the potential of integrating genomic and phenotypic data to enhance the robustness, resolution, and scalability of DUS testing in tomato.

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VC1 and the production of vicine and convicine in the genus Vicia

Vottonen, L. L.; Chang, W.; Pöysä, M.; Lampi, A.-M.; Tanskanen, J.; Schulman, A. H.; Stoddard, F. L.

2026-07-14 plant biology 10.64898/2026.07.09.737524 medRxiv
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Many Vicia species contain vicine and convicine (VC), which limit the use of faba bean and some vetches in food and feed. The first step in VC biosynthesis in V. faba is shared with the riboflavin pathway and attributed to VC1, a member of the ribAB family. Since riboflavin is ubiquitous to life, we examined the distribution of VC production in genus Vicia. Three accessions of each of 33 Vicia species were grown in glasshouse conditions to provide fresh seeds for VC analysis and leaves for DNA analysis. PCR was used to amplify fragments of the VC1/ribAB gene for sequencing, and these sequences were used to create a phylogenetic tree. COX1 and ITS2 sequences were used for examining the nucleotide diversity in the subgenera. VC and DNA sequences consistent with VC1 were found only in members of subgenus Vicia. In V. lathyroides, VC1 was present but no VC was detected. There was less sequence diversity in VC1/ribAB sequences of subgenus Cracca than in those of subgenus Vicia, suggesting that ribAB remained under stricter purifying selection than VC1. VC1 is confirmed as a prerequisite for the presence of VC, and the gene and its products are restricted to subgenus Vicia. HighlightThe favism-causing factors of vetches and faba bean, vicine and convicine, depend on the presence of the VC1 variant of the ribAB gene, which is found in only one subgenus.

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Plant regulator of flower bud differentiation in in vitro plants of Cymbidium tortisepalum var. longibracteatum with TDZ as the key initiator

WU, C. q.; ZHAO, T.; CAO, F.; LI, H.; LI, J.

2026-07-30 plant biology 10.64898/2026.07.29.741633 medRxiv
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BackgroundCymbidium tortisepalum var. longibracteatum is a Class II nationally protected endangered plant in China with significant economic value. AimThis study aimed to establish an efficient in vitro flowering system and identify key hormonal factors regulating flower bud differentiation. MethodsOrthogonal experiments and hormone treatments were performed to evaluate the effects of TDZ, 6-BA, NAA, IBA, PP333, ABA, and GA3 on flower bud induction in tissue-cultured plantlets. ResultsTDZ was identified as the key initiator of flower bud differentiation, as no flower buds were induced in TDZ-free treatments. The optimal hormone combination was 1.0 mg{middle dot}L-1 6-BA + 0.4 mg{middle dot}L-1 TDZ + 0.8 mg{middle dot}L-1 NAA + 1.6 mg{middle dot}L-1 IBA, achieving a flower bud induction rate of 23.33% and a normal flower bud rate of 20.00%. PP333 inhibited flower bud differentiation but reduced malformation; at 0.2 mg{middle dot}L-1 PP333, the normal flower bud rate reached 20.00%. GA3 pretreatment resulted in a flower bud induction rate of 12.04%, whereas ABA pretreatment showed no significant promoting effect on flower bud induction. ConclusionsThis study provides an efficient in vitro flowering system and key hormonal parameters for shortening the breeding cycle and elucidating orchid flowering mechanisms.

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CRISPR-Cas9 Induced Knockout of BEL5 in Tetraploid Potato: Optimized Methodology via Repeated de novo Regeneration and Impact on Tuberization

Zounkova, A.; Chirivi, D.; Pribylova, A.; Martignago, D.; Myslivcova, J.; Masek, T.; Fischer, L.; Betti, C.; Fornara, F.; Maskova, P.

2026-07-22 plant biology 10.64898/2026.07.21.739726 medRxiv
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CRISPR-Cas9 has emerged as a powerful tool for targeted genome editing in plants; however, its application in tetraploid potato (Solanum tuberosum ssp. tuberosum) remains challenging due to its vegetative propagation and complex highly heterozygous genome. Availability of whole-genome sequence data for the specific genotype is crucial to ensure complete knockout of all alleles of target genes while minimizing off-target mutations. In this study, using the tetraploid potato cultivar Desiree, we report, a complete CRISPR-Cas9-mediated knockout of the BEL5 gene, encoding a transcription factor, known as one of the key regulators driving tuber formation. We employed Agrobacterium-mediated transformation and demonstrated that repeated de novo regeneration could improve editing efficiency by promoting emergence of new mutations. BEL5 knockout plants exhibited a delayed onset of tuberization under inductive short-day conditions in hydroponics; however, their overall tuber yields were comparable to wild type plants. Based on our results, we propose a regulatory role of BEL5 in the timing of tuber onset but, unexpectedly, its dispensability for tuber development in modern cultivated potato. Besides providing functional insight into the BEL5 role in potato, this study includes a methodological approach for efficient CRISPR-Cas9 gene editing in this vegetatively propagated polyploid crop, along with strategies for detecting mutations in genes that lack clear phenotypic manifestation.

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Light spectral quality alters glandular trichome architecture more strongly than cannabinoid accumulation in Cannabis sativa

Dlaymi, S.;Perovich, R.;Kuo, C.;Liu, R.;Fetterley, V.;Lee, A.;Harris, C.;Todesco, M.;Samuels, A.;Cvetkovska, M.

2026-06-30 Plant Biology 10.64898/2026.06.29.735290 medRxiv
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The glandular trichomes in Cannabis sativa, found predominantly on female flowers, produce and store a variety of unique phytocannabinoids, increasingly studied for their use in medicinal applications. Maximizing yield and cannabinoid profiles requires the optimization of the environmental factors that regulate plant growth. Light plays a prominent role, both as an energy source but also as an important developmental signal. Thus, optimization of lighting strategies, particularly through customizable light-emitting diode (LED) fixtures, has become a major focus of controlled-environment cannabis research. Here, we focus on the effect of blue-enriched and far red-enriched light spectra on the morphological traits and biochemical profiles of two THCA-dominant varieties: Pineapple Cough and Rocky Fire #7. Spectral composition exerts modest and genotype-specific effects on the plant development, inflorescence biomass, and cannabinoid concentration but we demonstrate a positive correlation between total yield and plant height in both varieties, regardless of spectra. We also show that growth under far-red enriched light affects the visible pigmentation in both varieties with significantly lower chlorophyll levels and paler fan and sugar leaves. Finally, we demonstrate that far-red light consistently increased the trichome stalk length in both varieties, suggesting that spectral composition can alter trichome development and morphology. Our data offers insights into cannabis development and secondary chemical profiles in response to different light spectra, allowing growers to adjust light spectra to obtain desirable cannabis traits for industrial production.

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A first pangenomic framework for globe artichoke supports SNP-based varietal fingerprinting

Portis, E.;Vergnano, E.;Gaccione, L.;Acquadro, A.;Comino, C.;Carli, C.;Barchi, L.;Martina, M.

2026-06-26 Plant Biology 10.64898/2026.06.25.734495 medRxiv
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Globe artichoke (Cynara cardunculus var. scolymus L.) comprises a broad range of local ecotypes and varietal groups whose genetic diversity has been investigated through different molecular markers. However, recent advances in next-generation sequencing and pangenomics approaches provide new opportunities to capture genome-wide variation at higher resolution and to develop practical tools for varietal discrimination, traceability, and germplasm conservation. In this study, we developed the first pangenomic framework for cultivated artichoke and evaluated pangenome-informed SNP markers for varietal fingerprinting. Whole-genome resequencing data from the Italian local ecotype Asti Sori were integrated with publicly available genomic data from representative globe artichoke and cultivated cardoon accessions to construct and annotate a pangenome. Genome-wide SNP and presence/absence variation (PAV) analyses were combined with pangenome-anchored genotyping-by-sequencing (GBS) data from 45 accessions representing the main cultivated varietal groups. The pangenome revealed a largely conserved core gene repertoire alongside a smaller accessory component, with gene accumulation curves suggesting a tendency toward saturation within the sampled cultivated germplasm. SNP- and PAV-based analyses provided complementary views of accession relationships and consistently resolved the principal cultivated groups. Across the broader germplasm panel, pangenome-anchored GBS-derived SNPs identified well-supported phylogenetic clusters corresponding to recognized varietal types. A reduced panel of 50 SNPs, selected through iterative random subsampling, retained at least 90% of the genetic diversity captured by the full dataset and reproduced its main population structure. This compact pangenome-anchored marker set provides a practical foundation for varietal fingerprinting, DUS-oriented applications, traceability, and conservation of traditional globe artichoke germplasm. Validation across independent collections will be required before routine deployment.

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Bidirectional hybridization between Ulva prolifera and U. linza (Ulvophyceae, Chlorophyta): Evidence for compatibility and paternal chloroplast inheritance

Xu, Z. Z.; Zhao, J.; Jiang, P.

2026-07-22 genetics 10.64898/2026.07.18.739365 medRxiv
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Ulva prolifera and U. linza are closely related species, with abundant adult thalli and reproductive cells co-occurring extensively in time and space during the Yellow Sea green tides. Elucidating their hybridization compatibility is crucial for species delimitation, assessing interspecific gene flow, and evaluating the ecological impacts of green tides. Previous studies suggested asymmetric gamete compatibility (only U. prolifera mt+ x U. linza mt-), but lacked sex-linked markers to reliably identify hybrid diploids and their reproductive modes, and did not examine chloroplast inheritance. Here, we performed bidirectional crosses using sexual strains of different geographic origins from both parents, with sex-linked markers to quantify progeny genotypes, examine fertility and reproduction pathway of F1 hybrids, and trace chloroplast inheritance using the species-specific petB marker. Our results showed that: (1) F1 hybrids were obtained in both cross directions, with significantly higher frequency in the direct cross (U. linza mt+ x U. prolifera mt-), indicating no complete reproductive isolation in either direction; the biased compatibility likely reflected genetic background differences among the limited strain combinations in a single study. (2) A considerable number of germinated progeny arose from parthenogenesis of parental gametes. (3) F1 hybrids from both crosses could undergo meiosis to form gametes and develop into gametophytes; additionally, F1 from the reciprocal cross produced diploid spores for asexual reproduction, suggesting meiotic disturbance. (4) Chloroplasts were maternally inherited in selfing of U. prolifera parent, but in all F1 hybrids they were paternally inherited, indicating a potential reversal of the inheritance pattern due to interspecific hybridization. These findings provided new insights into the potential for genetic exchange between U. prolifera and U. linza.

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Cytogenomic signatures of hybridisation in the genus Carpobrotus reveal biased parental dominance

Pascual-Diaz, J. P.; Torres, M.; Bacovsky, V.; Horakova, L.; Kruzlicova, J.; Novotna, P.; Novoa, A.; Vitales, D.; Garcia, S.

2026-07-09 plant biology 10.64898/2026.07.03.736328 medRxiv
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14.8%
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O_LIHybridisation is frequently associated with plant invasions; however, its consequences for genome organisation and chromosome evolution remain poorly understood in invasive species. We investigated the extent of hybridisation in the invasive Carpobrotus edulis--acinaciformis hybrid complex and determined the cytogenomic contribution of parental species in hybrid accessions. C_LIO_LIWe combined whole-genome sequencing, population genomic analyses, genome size estimation, repeatome characterisation, chromosome counting and fluorescence in situ hybridisation to compare parental species and hybrid accessions from South Africa and the Mediterranean Basin. C_LIO_LIPopulation genomic analyses revealed widespread hybridisation and introgression, with most invasive accessions showing admixed ancestries. Pattersons D-statistic supported asymmetric allele sharing towards C. edulis. Hybrid accessions displayed genome sizes indistinguishable from C. edulis, whereas C. acinaciformis possessed significantly larger genomes. Repeatome analyses identified marked differences in repetitive DNA composition, particularly in satellite DNA abundance and chromosomal distribution. A newly identified satellite repeat (CarpoSat) showed contrasting chromosomal patterns between parental species, whereas hybrids resembled C. edulis satellite pattern. C_LIO_LIOur results demonstrate that Carpobrotus hybrid accessions are a swarm of later-generation hybrids and backcrosses showing a strong bias towards C. edulis, indicating asymmetric introgression. These findings highlight the value of integrating cytogenetic and genomic approaches to understand genome evolution in invasive hybrid complexes. C_LI

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CRISPR/Cas12a-mediated allele engineering of SmAPRR2 and SmGLK2 reveals complementary control of fruit peel and flesh chlorophyll pigmentation in eggplant

Martinez-Lopez, M.; Solana, A.; Arrones, A.; Toppino, L.; Vilanova, S.; Plazas, M.; Prohens, J.; Gramazio, P.

2026-07-29 plant biology 10.64898/2026.07.28.741273 medRxiv
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14.7%
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Eggplant (Solanum melongena L.) displays extensive fruit color diversity, in which chlorophyll-related pigmentation contributes to both external appearance and market value. Previous genetic studies identified SmAPRR2 and SmGLK2 as major candidate genes controlling uniform green pigmentation and green netting in fruit, respectively, but their individual and combined functional contributions had not been validated through targeted mutagenesis in a common genetic background. Here, we established a multiplex CRISPR/Cas12a system in eggplant accession MEL3, representing, to our knowledge, the first application of this nuclease for genome editing in eggplant. Transformation efficiency was 2.0%, but all 15 genotyped regenerants were edited, yielding four SmAPRR2 and six SmGLK2 alleles. Segregation and crossing enabled the recovery of six transgene-free lines carrying single or combined edited alleles. Disruption of SmGLK2 abolished the reticulated green netting pattern while preserving a uniformly green peel and the internal green ring. Conversely, disruption of SmAPRR2 reduced the background uniform peel pigmentation and eliminated the green ring while retaining green netting. Double mutants carrying disruptive alleles at both loci produced white fruits lacking internal green pigmentation, whereas putatively hypomorphic SmAPRR2 and SmGLK2 alleles generated intermediate phenotypes. Whole-genome resequencing identified only two predicted off-target sites under a canonical TTTV PAM search allowing up to four mismatches. Both were fully covered, and no edited-line-specific candidate variants were detected. These findings establish complementary and partially separable roles for SmAPRR2 and SmGLK2 in fruit peel and flesh chlorophyll pigmentation and demonstrate the potential of Cas12a for functional genomics, allele engineering, and precision breeding in eggplant.