Studies on the northeastern American native hops ( Humulus lupulus ssp . lupuloides) from the Canadian Maritimes are scarce. This study aimed to evaluate the genetic structure and diversity among 25 wild-collected hops from three Canadian Maritime provinces using microsatellite (simple sequence repeat (SSR)) markers. Based on 43 SSR markers, four distinct subgroups were found, with a low molecular variance (19%) between subgroups and a high variance (81%) within subgroups. The Nei’s unbiased genetic distance between clusters ranged from 0.01 to 0.08, the genetic distance between clusters 2 and 3 being the farthest and that between clusters 1 and 2 the closest. Cluster 2 captured the highest overall diversity. A total of 18 SSR markers clearly discriminated hop clones by detecting putative subspecies-specific haplotypes, differentiating clones of native-wild H. lupulus ssp . lupuloides from the naturalized old and modern hop cultivars. Seven of the 18 SSR markers also differentiated two clones from the same site from one another. The study is the first, using molecular markers, to identify SSR markers with potential for intellectual property protection in Canadian Maritimes hops. The SSR markers herein used can be prime tools for hop breeders and growers in the region.

Ascorbic acid (ASC) is a molecule naturally synthesized in plant cells, protecting against abiotic stresses by reducing reactive oxygen species (ROS), which cause oxidative damage. Aluminum (Al) toxicity is the major limiting factor on crop productivity in acidic soils, increasing ROS within cells and impairing the growth and development of plants. Exogenous antioxidant applications are an effective strategy to promote tolerance to abiotic stress. The objective was to evaluate the effect of foliar ASC applications (0, 50, 100, 200, and 400 mg L⁻¹ ASC) and their interaction with Al toxicity (0, 400 µM Al) in Star, an Al-sensitive cultivar of highbush blueberry. Significant increases of 1.6-fold in growth were observed in roots and leaves under treatment with 200 mg L⁻¹ ASC. In the same treatment, increased pigments and antioxidant activity (~1.2- to 2.3-fold) were observed concomitant with reduced lipid peroxidation. Positive correlations between organic acid exudation, the ASC/DHA ratio, and calcium levels were observed, whereas a negative correlation between lipid peroxidation and dehydroascorbate (DHA) was observed. Foliar ASC application also increased the ASC/DHA ratio in leaves and enhanced 2.2-fold organic acid exudation in the 200 mg L⁻¹ ASC treatment. The results suggest that foliar ASC applications improved redox balance and underscore the potential of ASC as a practical solution to enhance resilience in Al-sensitive plants.

Nitrogen (N), the most important macro-nutrient for plant growth and development, is a key factor that determines crop yield. Yet its excessive applications pollute the environment and are expensive. Hence, studying nitrogen use efficiency (NUE) in crops is fundamental for sustainable agriculture. Here, an association panel consisting of 123 flax accessions was evaluated for 21 NUE-related traits at the seedling stage under optimum N (N+) and N deficiency (N−) treatments to dissect the genetic architecture of NUE-related traits using a multi-omics approach integrating genome-wide association studies (GWAS), transcriptome analysis and genomic selection (GS). Root traits exhibited significant and positive correlations with NUE under N− conditions (r = 0.33 to 0.43, p < 0.05). A total of 359 QTLs were identified, accounting for 0.11% to 23.1% of the phenotypic variation in NUE-related traits. Transcriptomic analysis identified 1034 differentially expressed genes (DEGs) under contrasting N conditions. DEGs involved in N metabolism, root development, amino acid transport and catabolism and others, were found near the QTLs. GS models to predict NUE stress tolerance index (NUE_STI) trait were tested using a random genome-wide SNP dataset and a GWAS-derived QTLs dataset. The latter produced superior prediction accuracy (r = 0.62 to 0.79) compared to the genome-wide SNP marker dataset (r = 0.11) for NUE_STI. Our results provide insights into the QTL architecture of NUE-related traits, identify candidate genes for further studies, and propose genomic breeding tools to achieve superior NUE in flax under low N input.

Most cultivated potato (Solanum tuberosum) varieties are highly susceptible to common scab (Streptomyces scabei). The disease is widespread in all major potato production areas and leads to high economic losses and food waste. Varietal resistance is seen as the most viable and sustainable long-term management strategy. However, resistant potato varieties are scarce, and their genetic architecture and resistance mechanisms are poorly understood. Moreover, diploid potato relatives to commercial potatoes remain to be fully explored. In the current study, a panel of 384 ethyl methane sulfonate (EMS)-mutagenized diploid potato clones were evaluated for common scab coverage, severity, and incidence traits under field conditions, and genome-wide association studies (GWASs) were conducted to dissect the genetic architecture of their traits. Using the GAPIT-MLM and RTM-GWAS statistical models, and Mann–Whitney non-parametric U-tests, we show that 58 QTNs/QTLs distributed on all 12 potato chromosomes were associated with common scab resistance, 52 of which had significant allelic effects on the three traits. In total, 38 of the 52 favorable QTNs/QTLs were found to be pleiotropic on at least two of the traits, while 14 were unique to a single trait and were found distributed over 3 chromosomes. The identified QTNs/QTLs showed low to high effects, highlighting the quantitative and multigenic inheritance of common scab resistance. The QTLs/QTNs associated with the three common scab traits were found to be co-located in genomic regions carrying 79 candidate genes playing roles in plant defense, cell wall component biosynthesis and modification, plant–pathogen interactions, and hormone signaling. A total of 61 potato clones were found to be tolerant or resistant to common scab. Taken together, the data show that the studied germplasm panel, the identified QTNs/QTLs, and the candidate genes are prime genetic resources for breeders and biologists in breeding and targeted gene editing.

Nitrogen (N) is the most important macro-nutrient for plant growth and development, which not only results in the highest cost in crop production but may also lead to environmental pollution. Hence, there is a need to develop N and use efficient genotypes, a prerequisite for which is a better understanding of N stress adaptation. Here, responses of two contrasting linseed accessions at the seedling stage were assessed for N stress-induced changes in twelve phenotypic traits and for gene expression profiling in the roots. The results showed that nine out of twelve phenotypic traits were affected under N stress conditions, and include total root length (TRL), root tips (RT), shoot dry weight (SDW), root dry weight (RDW), root-to-shoot ratio (R/S), plant nitrogen content (PNC), shoot nitrogen content (SNC), root nitrogen content (RNC), and nitrogen use efficiency (NUE). For example, under N stress, the TRL, RDW, SDW, PNC, SNC, and RNC showed reductions of 7.1, 7.6, 16.0, 43.7, 43.3, and 38.7%, respectively. The N-efficient (NE) genotype outperformed the N-inefficient (NI) genotype for all root and shoot traits and NUE under N stress and N normal conditions. Transcriptome analysis identified 1034 differentially expressed genes (DEGs) under the contrasting N conditions and uncovered the opposite responses of the two linseed genotypes to N starvation at the gene expression level. DEGs included 153 transcription factors distributed in 27 families, among which ERF, MYB, NAC, and WRKY were the most represented. In addition, DEGs involved in N absorption and transport, root development, amino acid transport, and antioxidant activity were found to be differentially expressed. The candidate genes identified in the current study are purported for their roles in N metabolism in other crops and might also play a pivotal role in N stress adaptation in linseed, and therefore could be useful for further detailed research on N stress response in linseed, paving the way toward developing N-efficient linseed cultivars with improved root system architecture.