Genome-wide analysis of AP2/ERF genes identifies HpERF144 as a regulator of salt tolerance and phenylpropanoid metabolism in Herpetospermum pedunculosum.

Genome-wide AP2/ERF analysis identifies HmaERF87 as a positive regulator of Hydrangea macrophylla leaf spot resistance

Characterization of the AP2/ERF gene family in Fritillaria thunbergii and functional evaluation of FtAP2/ERF-61 in conferring tolerance to drought and salt stress.

BACKGROUND The APETALA 2/ethylene-responsive element binding factors (AP2/ERFs) are crucial modulators of plant development and stress responses. Fritillaria thunbergii is an important medicinal herb with considerable therapeutic efficacy. However, despite its importance, no systematic identification and functional characterization of the AP2/ERF gene family in F. thunbergii has been reported to date. RESULTS This study identified a total of 71 AP2/ERF genes in F. thunbergii and classified them into 11 subgroups, with genes in the same subgroup exhibiting similar motifs and domains. Expression analysis revealed that these genes displayed distinct expression patterns under salt and drought stress, and Gene Ontology annotation indicated their involvement in stress responses and hormone signaling. Further analysis demonstrated that FtAP2/ERF-61 responded to mannitol, NaCl, ethylene, abscisic acid, and jasmonic acid. The FtAP2/ERF-61 protein consisted of 352 amino acids, contained a conserved AP2/ERF domain, was localized to the nucleus, and possessed transcriptional activation activity. Overexpression of FtAP2/ERF-61 in Arabidopsis thaliana significantly enhanced germination rates and growth status under salt and osmotic stress, while reducing hydrogen peroxide and malondialdehyde accumulation, and upregulating the expression of stress-responsive genes and antioxidant enzyme genes. CONCLUSION This study provided the systematic identification of AP2/ERF family members in F. thunbergii and demonstrated that FtAP2/ERF-61 conferred dual stress tolerance by activating the ROS-scavenging system and stress-responsive genes, thereby offering new genetic resources and a theoretical basis for molecular breeding of stress-tolerant medicinal plants.

Identification of salt and drought resistance function of maize transcription factor ZmEREB54

AP2/ERF (APETALA2/ethylene-responsive factor) represents one of the largest transcription factor superfamilies in plants, playing crucial roles in regulating plant growth and development as well as responding to abiotic stresses. Investigating the functions of maize (Zea mays L.) AP2/ERF family genes will provide novel genetic resources for maize genetic improvement. In this study, the AP2/ERF transcription factor superfamily member ZmEREB54 (GRMZM2G020054, Gene ID: 100,278,463) was cloned from maize and was systematically analyzed functionally. The full-length CDS of ZmEREB54 gene was 561 bp, encoding 186 amino acids with a typical AP2/ERF conserved domain. Its promoter region contained cis-acting elements associated with responses to various abiotic stresses and hormones. Maize expression pattern analysis revealed that ZmEREB54 was highly expressed in V12 roots, with significant expression changes under osmotic stress, drought, high salinity, and treatments with abscisic acid (ABA) and jasmonic acid (JA). Phenotypic analysis showed that transgenic Arabidopsis thaliana over-expressing ZmEREB54 exhibited significantly longer roots compared to wild-type plants under high salinity, drought, osmotic stress, and hormone treatments (JA, ABA). Stress-responsive marker genes RD29A and RD22 were upregulated in the transgenic A. thaliana lines. The significantly decreased malondialdehyde (MDA) accumulation and markedly increased peroxidase (POD) activity in transgenic A. thaliana further demonstrate the improvement of its stress tolerance. Yeast two-hybrid (Y2H) assays revealed an interaction between ZmEREB54 and ZmMADS24.6, suggesting potential cooperative regulation of ZmEREB54 and ZmMADS24.6 in maize root development and stress responses. This study establishes a solid foundation for further clarifying the biological functions and molecular mechanisms of ZmEREB54 in regulating maize root growth and development, as well as responding to drought and salt stresses.

Genome-Wide Characterization of SnRK Gene Family in Mangrove Plant Avicennia marina and Function of AmSnRK2.7-AmENO2 Module in Response to Salinity.

Sucrose non-fermenting-1-related protein kinase (SnRK) is a plant serine/threonine kinase that mediates stress signaling, yet its function in the mangrove Avicennia marina remains unexplored. In this study, we identified 46 SnRK genes in A. marina, classifying them into three subfamilies with high phylogenetic conservation. Family expansion occurred mainly through 20 segmental duplication events under purifying selection (Ka/Ks < 1). Promoter regions were enriched in stress- and hormone-responsive elements, and expression profiling showed distinct tissue-specific and stress-responsive patterns. Our study specifically focused on the functional characterization of AmSnRK2.7. AmSnRK2.7-overexpressed Arabidopsis thaliana increases salt tolerance by altering the expression of ion transport genes and mediating Na+ efflux from the roots. Further investigation revealed that AmSnRK2.7 interacts with and phosphorylates AmENO2 (enolase, a key enzyme in the glycolysis pathway). Meanwhile, measurements of ATP content in wild type, AmSnRK2.7-overexpressed Arabidopsis lines and the atsnrk2.6 (homologous gene of AmSnRK2.7 in A. thaliana) mutant confirm that the AmSnRK2.7-AmENO2 module can affect the energy-driven Na+ efflux. Our findings provide key insights into the role of SnRK gene family in mangrove adaptation to saline intertidal habitat, and suggest AmSnRK2.7-AmENO2 module plays a role in salt tolerance.

Comprehensive characterization of the genes in AP2/ERF family and their involvement in salt–alkali stress response during Nelumbo nucifera seed germination

Nelumbo nucifera Gaertn. is an economically and ecologically important aquatic plant, but its growth and productivity are severely constrained by soil salinization and alkalization. AP2/ERF transcription factors are key regulators of plant abiotic stress responses; however, their roles in salt–alkali tolerance in N. nucifera remain largely unclear. In this study, we performed a genome-wide identification and characterization of the AP2/ERF gene family in N. nucifera , followed by phylogenetic, structural, and physicochemical analyses. A total of 101 AP2/ERF genes were identified and classified into five subfamilies, showing both evolutionary conservation and species-specific divergence compared with Arabidopsis thaliana. Physiological analyses during seed germination under salt–alkali stress revealed significant changes in malondialdehyde content, proline accumulation, and antioxidant enzyme activities, suggesting activation of oxidative stress defense and osmotic adjustment mechanisms. Transcriptome profiling of seedlings treated with 150 mM salt–alkali solution for 5 and 10 days identified 7,350 differentially expressed genes, including 29 AP2/ERF members responsive to stress. Among them, 13 genes, including AP2-9, ERF23, ERF15, ERF31, ERF34 , and DREB21 , were consistently upregulated under both treatments, indicating their potential roles in stress adaptation. qRT-PCR validation further confirmed the sustained upregulation of key genes AP2-9, ERF23, ERF34, and DREB21 , consistent with transcriptome data. Overall, this study provides the first comprehensive overview of the AP2/ERF gene family in N. nucifera and identifies candidate regulators involved in salt–alkali stress responses, offering valuable insights into the molecular mechanisms of stress adaptation and potential genetic resources for breeding salt–alkali tolerant aquatic plants.

The transcription factor BpERF1A enhances drought tolerance in Betula platyphylla by activating dehydrin and ROS scavenging through interaction with BpRAV1

Abstract Although ERF transcription factors (TFs) play critical roles in abiotic stress tolerance, the molecular mechanisms underlying this role remain incompletely understood. This study identified BpERF1A in birch (Betula platyphylla) as a drought-responsive TF through co-expression regulatory network analysis. Expression of BpERF1A was stalwartly induced by drought stress, and drought treatment markedly boosted its promoter activity. Functional analyses demonstrated that overexpression of BpERF1A markedly improved drought tolerance compared with wild-type (WT) birch, whereas its repression increased drought sensitivity. Overexpression lines also exhibited higher antioxidant enzyme activities and proline content relative to WT. Chromatin immunoprecipitation-polymerase chain reaction, yeast one-hybrid and dual-luciferase (dual-LUC) assays confirmed that BpERF1A directly binds to G-box elements in the promoters of BpDHN (dehydrin) and BpAOS (allene oxide synthase), activating their transcription. Furthermore, overexpression of BpDHN/BpAOS enhanced drought tolerance and promoted reactive oxygen species (ROS) scavenging in transgenic plants. Protein–protein interaction analysis using bimolecular fluorescence complementation revealed that BpERF1A interacts with BpRAV1 to form a heterodimer, which further enhances BpERF1A binding to the BpDHN promoter and its transcriptional activation. Collectively, these findings establish a central role for the BpERF1A regulatory module in drought acclimation and highlight its synergistic interaction with BpRAV1, providing an effective strategy to enhance drought tolerance through improved ROS scavenging capacity.