Seed storability is an important trait for improving grain quality and germplasm conservation, but little is known about the regulatory mechanisms and gene networks involved. MicroRNAs (miRNAs) are small non-coding RNAs regulating the translation and accumulation of their target mRNAs by means of sequence complementarity and have recently emerged as critical regulators of seed germination. Here, we used the germinating embryos of two maize inbred lines with significant differences in seed storability to identify the miRNAs and target genes involved. We identified a total of 218 previously known and 448 novel miRNAs by miRNA sequencing and degradome analysis, of which 27 known and 11 newly predicted miRNAs are differentially expressed in two maize inbred lines, as measured by Gene Ontology (GO) enrichment analysis. We then combined transcriptome sequencing and real-time quantitative polymerase chain reaction (RT-PCR) to screen and confirm six pairs of differentially expressed miRNAs associated with seed storability, along with their negative regulatory target genes. The enrichment analysis suggested that the miRNAs/target gene mediation of seed storability occurs via the ethylene activation signaling pathway, hormone synthesis and signal transduction, as well as plant organ morphogenesis. Our results should help elucidate the mechanisms through which miRNAs are involved in seed storability in maize.

The NAC gene family has transcription factors specific to plants, which are involved in development and stress response and adaptation. In this study, ZmNAC89, an NAC gene in maize that plays a role in saline–alkaline tolerance, was isolated and characterized. ZmNAC89 was localized in the nucleus and had transcriptional activation activity during in vitro experiments. The expression of ZmNAC89 was strongly upregulated under saline–alkaline, drought and ABA treatments. Overexpression of the ZmNAC89 gene in transgenic Arabidopsis and maize enhanced salt tolerance at the seedling stage. Differentially expressed genes (DEGs) were then confirmed via RNA-sequencing analysis with the transgenic maize line. GO analyses showed that oxidation–reduction process-regulated genes were involved in ZmNAC89-mediated salt–alkaline stress. ZmNAC89 may regulate maize saline–alkali tolerance through the REDOX pathway and ABA signal transduction pathway. From 140 inbred maize lines, 20 haplotypes and 16 SNPs were found in the coding region of the ZmNAC89 gene, including the excellent haplotype HAP20. These results contribute to a better understanding of the response mechanism of maize to salt–alkali stress and marker-assisted selection during maize breeding.

The environmental effects of genetically modified crops are now a global concern. It is important to monitor the potential environmental impact of transgenic corn after commercial release. In rhizosphere soil, plant roots interact with soil enzymes and microfauna, which can be affected by the transgenes of genetically modified crops. To determine the long-term impact of transgenic plant cultivation, we conducted a field study for 3 consecutive years (2018–2020) and observed the enzyme activities and nematode populations in plots planted with transgenic maize BQ-2, non-transgenic wild-type maize (Qi319), and inbred line B73. We took soil samples from three cornfields at four different growth stages (V3, V9, R1, and R6 stages); determined soil dehydrogenase, urease, and sucrase activities; and collected and identified soil nematodes to the genus level. The results demonstrated seasonal variations in dehydrogenase, urease, and sucrase activities. However, there was a consistent trend of change. The generic composition and diversity indices of the soil nematodes did not significantly differ, although significant seasonal variation was found in the individual densities of the principal trophic groups and the diversity indices of the nematodes in all three cornfields. The results of the study suggest that a 3-year cultivation of transgenic corn had no significant effects on soil enzyme activity and the soil nematode community. This study provides a theoretical basis for the environmental impact monitoring of transgenic corn.

Maize is an essential staple food, and its genetic diversity plays a central role in breeding programs aimed at developing climate-adapted cultivars. Constructing a representative core germplasm set is necessary for the efficient conservation and utilization of maize genetic resources. In this study, we analyzed 588 cultivated maize accessions using agronomic traits such as plant morphology and yield traits such as ear characteristics and single-nucleotide polymorphisms (SNPs) to assess molecular diversity and population structure and to construct a core collection. Nineteen phenotypic traits were evaluated, revealing high genetic diversity and significant correlations among most quantitative traits. The optimal sampling strategy was identified as “Mahalanobis distance + 20% + deviation sampling + flexible method.” Whole-genome genotyping was conducted using the Maize6H-60K liquid phase chip. Population structure analysis, principal component analysis, and cluster analysis divided the 588 accessions into six subgroups. A core collection of 172 accessions was selected based on both phenotypic and genotypic data. These were further evaluated for salt–alkali tolerance during germination, and cluster analysis classified them into five groups. Sixty-five accessions demonstrated salt–alkali tolerance, including 18 with high resistance. This core collection serves as a valuable foundation for germplasm conservation and utilization strategies.

GLABROUS1 enhancer-binding protein (GeBP) family members are plant-specific transcription factors involved in growth, development, and environmental responses. However, the characteristics and stress-responsive patterns of this family in maize (Zea mays L.), particularly during seed aging and saline–alkali stress, remain insufficiently understood. We identified 19 ZmGeBP genes and classified their encoded proteins into four phylogenetic groups together with homologs from sorghum and rice. Duplication and synteny analyses showed that segmental duplication was the predominant duplication pattern detected in maize and that collinear relationships were retained among the three grasses. The ZmGeBP promoters contained cis-acting elements associated with development, light, phytohormone responses, and stress. RT-qPCR analysis of seven selected genes revealed temporal and genotype-dependent expression patterns during artificial seed aging and saline–alkali stress. Subcellular localization confirmed nuclear targeting of ZmGeBP8, and dual-luciferase reporter assays showed that ZmOCL13 reduced ZmGeBP8 promoter activity, suggesting a potential repressive effect. Overall, these findings elucidate the molecular features of maize ZmGeBP genes and establish a framework for validating their roles in stress resilience.