Background: Frogeye leaf spot (FLS) is a destructive fungal disease that affects soybean production. The most economical and effective strategy to control FLS is the use of resistant cultivars. However, the use of a limited number of resistant loci in FLS management will be countered by the emergence of new high-virulence Cercospora sojina races. Therefore, we identified quantitative trait loci (QTL) that control resistance to FLS and identified novel resistant genes using a genome-wide association study (GWAS) on 234 Chinese soybean cultivars. Results: A total of 30,890 single nucleotide polymorphism (SNP) markers were used to estimate linkage disequilibrium (LD) and population structure. The GWAS results showed four loci (p < 0.0001) distributed over chromosomes (Chr.) 5 and 20, that are significantly associated with FLS resistance. No previous studies have reported resistance loci in these regions. Subsequently, 45 genes in the two resistance-related haplotype blocks were annotated. Among them, Glyma20g31630 encoding pyruvate dehydrogenase (PDH), Glyma05g28980, which encodes mitogen-activated protein kinase 7 (MPK7), and Glyma20g31510, Glyma20g31520 encoding calcium-dependent protein kinase 4 (CDPK4) in the haplotype blocks deserves special attention. Conclusions: This study showed that GWAS can be employed as an effective strategy for identifying disease resistance traits in soybean and narrowing SNPs and candidate genes. The prediction of candidate genes in the haplotype blocks identified by disease resistance loci can provide a useful reference to study systemic disease resistance.

Soybean root rot, a soil-borne fungal disease, is caused by multiple pathogens that seriously affect soybean production. During spring 2021, 92 pathogenic fungal strains were isolated from soybean plants with root rot in Hailun City, Heilongjiang Province, China. Through morphological and molecular identification, these strains were identified as Fusarium oxysporum (39.1%), F. asiaticum (30.4%), F. graminearum (13.0%), Pythium macrosporum (8.7%), and Rhizoctonia solani (8.7%). Among them, F. oxysporum was the dominant species, and F. asiaticum, not previously reported as a soybean root rot pathogen in Northeast China. Approximately 50% of the F. asiaticum isolates were moderately pathogenic. In addition, F. asiaticum had a wide host range, infecting black soybean, French bean, white hyacinth bean, mung bean, and adzuki bean but not corn, peanut, rice, and oat roots. Regarding field management, fludioxonil and pyraclostrobin had the best control effects of 73.8% and 69.4%, with EC₅₀ values of 0.0029–0.0071 μg·mL⁻¹ and 0.0045–0.0076 μg·mL⁻¹, respectively. The study reported that F. asiaticum is a pathogen causing soybean root rot in northeast China. The application of chemical fungicides and non-host crop rotation can effectively control the disease caused by F. asiaticum.

Cold stress critically restricts maize seedling growth in Northeast China, yet the mechanism by which cold priming (CP) enhances cold tolerance through proline–nitrogen metabolic networks remains unclear. This study systematically investigated CP’s synergistic regulation in cold-tolerant (Heyu27) and cold-sensitive (Dunyu213) maize using a two-phase temperature regime (priming induction/stress response) with physiological and multivariate analyses. CP alleviated cold-induced photosynthetic inhibition while maintaining a higher chlorophyll and photosynthetic rate, though biomass responses showed varietal specificity, with Heyu27 minimizing growth loss through optimized carbon–nitrogen allocation. Antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were pre-activated during early stress, effectively scavenging reactive oxygen species (ROS) and reducing malondialdehyde (MDA) accumulation, with Heyu27 showing superior redox homeostasis. CP enhanced proline accumulation via bidirectional enzyme regulation (upregulating ∆¹-pyrroline-5-carboxylate synthase/reductase [P5CS/P5CR], inhibiting proline dehydrogenase [ProDH]) and reprogrammed nitrogen metabolism through glutamate dehydrogenase/isocitrate dehydrogenase (GDH/ICDH)-mediated ammonium conversion to glutamate, alleviating nitrogen dysregulation while supplying proline precursors. Principal component analysis revealed divergent strategies: Heyu27 prioritized proline–antioxidant synergy, whereas Dunyu213 emphasized photosynthetic adjustments. These findings demonstrate that CP establishes “metabolic memory” through optimized proline–nitrogen coordination, synergistically enhancing osmoregulation, reactive oxygen species (ROS) scavenging, and nitrogen utilization. This study elucidates C₄-specific cold adaptation mechanisms, advancing cold-resistant breeding and stress-resilient agronomy.

Soybean frogeye leaf spot (FLS) disease has been reported globally and is caused by the fungus Cercospora sojina, which affects the growth, seed yield, and quality of soybean. Among the 15 physiological microspecies of C. sojina soybean in China, Race 7 is one of the main pathogenic microspecies. A few genes are involved in resistance to FLS, and they cannot meet the need to design molecular breeding methods for disease resistance. In this study, a soybean recombinant inbred line (RIL3613) population and a germplasm resource (GP) population were planted at two sites, Acheng (AC) and Xiangyang (XY). Phenotypic data on the percentage of leaf area diseased (PLAD) in soybean leaves were obtained via image recognition technology after the inoculation of seven physiological species and full onset at the R3 stage. Quantitative trait loci (QTLs) and quantitative trait nucleotides (QTNs) were mapped via linkage analysis and genome-wide association studies (GWASs), respectively. The resistance genes of FLS were subsequently predicted in the linkage disequilibrium region of the collocated QTN. We identified 114 QTLs and 18 QTNs in the RIL3613 and GP populations, respectively. A total of 14 QTN loci were colocalized in the two populations, six of which presented high phenotypic contributions. Through haplotype–phenotype association analysis and expression quantification, three genes (Glyma.06G300100, Glyma.06G300600, and Glyma.13G172300) located near molecular markers AX-90524088 and AX-90437152 (QTNs) are associated with FLS Chinese Race 7, identifying them as potential candidate resistance genes. These results provide a theoretical basis for the genetic mining of soybean antigray spot No. 7 physiological species. These findings also provide a theoretical basis for understanding the genetic mechanism underlying FLS resistance in soybeans.

Drought stress markedly constrains soybean yields; however, progress in breeding has been limited by reliance on single-trait selection. Effective drought

The GARP transcription factor family is integral to the regulation of plant growth, development, hormone signaling pathways, circadian rhythms, and responses to both biotic and abiotic stressors. Despite its recognized importance, a comprehensive characterization of the GARP gene family in Glycine max remains unexplored. In this study, we identified 126 GmGARP genes across the 16 chromosomes of G. max and elucidated their diverse physicochemical properties. Phylogenetic classification grouped the GmGARP genes into eight distinct subfamilies, based on conserved motifs and gene structures, suggesting functional and evolutionary conservation within these clusters. The discovery of 56 segmentally duplicated gene pairs highlights gene duplication as a key driver of family expansion. Promoter analysis revealed various cis-regulatory elements, while expression profiling demonstrated that GmGARP genes possess significant tissue specificity. Furthermore, qRT-PCR analysis indicated that GmGARP genes are highly responsive to exogenous hormones, such as ABA, MeJA, and GA, as well as to abiotic stresses, including cold, salt, and drought conditions. Notably, GmGARP120 and GmGARP98 contain specific cis-elements linked to hormone responses, with their interaction verified through yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays. Additionally, 11,195 potential target genes were predicted, underscoring the regulatory potential of the GmGARP transcription factors. These findings provide significant insights into the GmGARP gene family, laying a strong foundation for future studies on its role in G. max development and adaptive responses to environmental stressors.