Lead (Pb) severely impairs plant growth, yet the role of WRKY transcription factors in Pb tolerance in maize remains largely unknown. Here, we identified a Pb-responsive WRKY transcription factor, ZmWRKY4, whose transcript levels were rapidly and strongly induced in maize leaves following Pb exposure. Physiological and biochemical analyses showed that overexpression of ZmWRKY4 substantially enhanced Pb tolerance in maize. Transgenic lines exhibited significantly lower malondialdehyde (MDA) levels and reduced electrolyte leakage than wild-type plants. In addition, ZmWRKY4 overexpression increased catalase (CAT) activity and effectively limited H₂O₂ accumulation. Further analyses revealed that ZmWRKY4 positively regulates ZmCAT1, a key antioxidant gene involved in H₂O₂ scavenging, under Pb stress. Electrophoretic mobility shift assays and ChIP-qPCR collectively confirmed that ZmWRKY4 directly binds to W-box elements within the ZmCAT1 promoter in vivo and in vitro, thereby activating its transcription. Together, these findings define a previously uncharacterized ZmWRKY4-ZmCAT1 regulatory module that enhances antioxidant capacity and mitigates oxidative damage during Pb stress. This work provides new insights into the molecular mechanisms underlying heavy metal tolerance in maize and identifies a promising genetic target for developing Pb-resilient crop varieties.

Introduction: Abiotic stressors, particularly saline–alkali stress, restrict plant growth and development. Rosa rugosa , which grows in coastal areas and exhibits high saline–alkali tolerance, serves as an ideal model for analyzing rose response mechanisms to saline–alkali stress (SAS). However, its response mechanisms have not yet been elucidated. Methods: This study examined SAS using a 150 mmol·L ⁻¹ saline–alkali solution and analyzed the physiological and molecular response mechanisms using physiological and biochemical indicators and high-throughput RNA-sequencing technology. Results: Under SAS, reactive oxygen species accumulation increased, resulting in extensive oxidative damage to cell membranes. In response, the superoxide dismutase, peroxidase, and catalase activities, along with the contents of soluble sugars, soluble proteins, and proline increased. Furthermore, 325, 2,197, 4,266, and 6,842 differentially expressed genes (DEGs) were identified at 6, 12, 24, and 48 h of SAS, respectively. Functional annotation and pathway enrichment analyses indicated that DEGs were primarily involved in cell wall organization, enzyme activity, biosynthesis of secondary metabolites, and photosynthesis pathways. Several structural genes from the phenylpropanoid biosynthesis pathway, including PAL , 4CL , HCT , CCR , COMT , CHS , CHI , and DFR , were identified by qRT-PCR, which positively responded to SAS and peaked at 12 h. Weighted gene co-expression network analysis revealed that PKS likely functions as the hub gene in the secondary metabolic pathway responding to SAS. Discussion: This study advances understanding of saline–alkali resistance mechanisms, and the identified genes and metabolic pathways can enhance future rose breeding efforts.

NAC transcription factors are key regulators involved in diverse cellular processes, stress responses, and developmental pathways in plants. However, their roles in female cone development of Torreya grandis, a representative gymnosperm species, remain largely unexplored. In this study, we performed a comprehensive identification and analysis of NAC transcription factors in T. grandis to investigate their potential functions in female cone development. A total of 82 TgNAC members containing conserved NAM domains were identified, distributed unevenly across 11 chromosomes. Phylogenetic analysis with Arabidopsis NACs classified them into 15 groups, with TgNACs represented in 10 groups and showing a notable enrichment in the TERN clade on chromosome 2. Promoter cis-element analysis revealed correlations between regulatory elements and expression patterns. Tissue-specific expression profiling indicated clear functional specialization, with some TgNACs showing no detectable expression in the examined tissues. During female cone development, several TgNACs were highly expressed in the early stages, whereas TgNAC72, TgNAC76 and TgNAC82 were upregulated during the latter stages. Among these, TgNAC72 exhibited the highest overall expression level. Subcellular localization confirmed TgNAC72 is localized in the nucleus. Dual-luciferase assays further demonstrated that TgNAC72 activates the TgBGLU13 promoter, suggesting its role in starch and sucrose metabolism. Collectively, these findings provide novel insights into the regulatory involvement of TgNACs in reproductive organ development.