Maize (Zea mays L.) is one of the most important food crops. Salt stress can hinder crop growth and development, but the molecular mechanisms underlying maize’s response to salt tolerance remain unclear. In this study, we conducted comparative transcriptome, metabolome, and physiological analyses of a salt-tolerant maize inbred line (J1285) subjected to different NaCl concentrations during the seedling stage. The results demonstrated that, with increasing salt concentration, seedling growth parameters and antioxidant enzyme activities (SOD, POD, CAT) exhibited initially increases before subsequently decreasing, peaking at 50–150 mmol/L. Transcriptome data analysis revealed that the experimental groups subjected to 50, 100, 150, and 200 mmol/L treatments had 375, 1043, 2504, and 2328 differentially expressed genes (DEGs) compared to the control group, respectively. Additionally, through GO and KEGG analysis, we found that the DEGs were primarily enriched in the MAPK signaling pathway and plant hormone signal transduction, especially the abscisic acid (ABA) signaling pathway, both of which play instrumental roles in orchestrating the maize response to salt-induced stress. Transcription factors involved in the salt stress response, including WRKY, TIFY, bZIP, and bHLH, were identified. Metabolomic data analysis revealed that the experimental groups subjected to 50, 100, 150 and 200 mmol/L treatments had 44, 335, 278, and 550 differentially expressed metabolites (DEMs) compared to the control group, respectively. The DEMs were mainly enriched in metabolic pathways and the biosynthesis of secondary metabolites. Transcriptomics and metabolomics combined analysis were performed on J1285 seedling leaves, and it was found that the co-enrichment pathways included starch and sucrose metabolism, linoleic acid metabolism, α-linolenic acid metabolism, phenylpropanoid biosynthesis pathway, etc. Collectively, these results will aid in identifying resistance genes and elucidating the molecular mechanisms underlying salt tolerance for maize.

MADS-box transcription factors play critical roles in plant development and stress responses. In this study, we identified 114 LuMADS genes in flax (Linum usitatissimum L.) and analyzed their phylogenetic relationships, gene structure, conserved motifs, miRNA targets, and expression patterns. We classified 45 LuMADS proteins as type I and 69 as type II, further subdivided into 11 subfamilies. Notably, lus-miR396 and lus-miR156 were identified as primary miRNA targets. Cis-acting elements in the promoter regions suggested roles in hormone and stress responses. Expression analysis revealed type II LuMADS genes were associated with floral organ formation and abiotic stresses such as cold, drought, and salt. This research provides insights for improving flax stress resistance and breeding.

The WOX (WUSCHEL-related homeobox) gene family plays pivotal roles in plant growth, development, and responses to biotic/abiotic stresses. Flax (Linum usitatissimum L.), a globally important oilseed and fiber crop, lacks a comprehensive characterization of its WOX family. Here, 18 LuWOX genes were systematically identified in the flax genome through bioinformatics analyses. Phylogenetic classification grouped these genes into three clades: Ancient, Intermediate, and WUS Clades, with members within the same clade exhibiting conserved exon–intron structures and motif compositions. Promoter analysis revealed abundant cis-acting elements associated with hormone responses (MeJA, abscisic acid) and abiotic stress adaptation (anaerobic induction, drought, low temperature). Segmental duplication events (nine gene pairs) contributed significantly to LuWOX family expansion. Protein–protein interaction networks implicated several LuWOX proteins in stress-responsive pathways. Expression profiling demonstrated that most LuWOX genes were highly expressed in 5-day-post-anthesis (DPA) flowers and embryonic tissues. qRT-PCR validation further uncovered distinct expression patterns of LuWOX genes under cold, drought, and salt stresses. This study established a foundational framework for leveraging LuWOX genes to enhance stress tolerance in flax breeding and functional genomics.

Low temperature during early spring severely impairs maize germination, leading to significant yield losses. To elucidate the mechanisms underlying cold tolerance at the germination stage, we compared two cold-tolerant maize inbred lines (AM and CM) with a cold-sensitive line (BM) under control (25 °C) and chilling (6 °C) conditions. Phenotypic observations showed that AM and CM maintained high germination rates and exhibited enhanced coleoptile elongation under cold stress, whereas BM displayed substantial growth inhibition. Cold-tolerant lines accumulated less malondialdehyde and showed markedly higher SOD and POD activities, indicating a stronger antioxidant defense. Transcriptome profiling revealed that cold tolerance is associated with a more robust transcriptional response in AM and CM, characterized by significant activation of the phenylpropanoid and flavonoid biosynthesis pathways. Among the differentially expressed genes, the class III peroxidase gene ZmPER5 was strongly upregulated in AM and CM but only weakly induced in BM, suggesting its central role in reinforcing the cell wall structure and enhancing ROS-scavenging capacity under chilling conditions. Other lignin- and flavonoid-related genes, including ZmHCT4 and ZmCYP75, also exhibited genotype-specific induction patterns consistent with cold tolerance. qRT-PCR validation confirmed the RNA-seq expression trends. These results demonstrate that maize cold tolerance during germination relies on the coordinated enhancement of antioxidant enzyme activity, activation of phenylpropanoid-derived lignin biosynthesis, and accumulation of protective flavonoids. The identified candidate genes, especially ZmPER5, provide valuable targets for improving cold tolerance in maize breeding.

Lodging is a key factor affecting maize yield and harvestability. This study utilized Reid population baselines and their improved lines as female parents and No-Reid population baselines and their improved lines as male parents to form 48 incomplete diallel crosses. The genetic improvement effects, combining ability, and heterosis of three lodging resistance-related traits (stem tension, puncture strength, and crushing strength at the third internode) were analyzed. Regarding genetic improvement, the results indicated that all three traits were significantly improved in the improved lines compared to the baselines, with improvements increasing in each round. Combining ability analysis showed positive general combining ability (GCA) effects for the improved lines J133A, JM25, JM115, and JM1895 in all three traits, with higher GCA values than the baselines and first-round improved lines. Heterosis analysis revealed the highest advantages for the combinations J133A × JM115 (stem tension), JM25 × JM115 (crushing strength), and J133A × J1865 (puncture strength). These findings suggest that the improved female lines J133A and JM25, along with male lines JM115 and JM1895, not only possess strong lodging resistance but also exhibit high yield potential in the cross J133A × JM115, offering new materials and varieties for maize mechanization.

Northern corn leaf blight is caused by Exserohilum turcicum and poses a significant threat to maize yields. Therefore, it is of vital importance to explore