Search Results (216)

Granule-bound starch synthase (GBSS) is primarily recognized for its role in amylose production and starch granule formation in plant plastids. While its biochemical function in storage organs has been well documented, its broader contribution to plant growth and stress adaptation remains less defined. To explore these aspects, the maize gene ZmGBSS1 was ectopically expressed in Arabidopsis thaliana and its physiological effects were examined. Subcellular localization assays confirmed that ZmGBSS1 is specifically localized to chloroplasts. Phenotypic analysis of transgenic lines revealed that overexpression of ZmGBSS1 significantly altered early seedling development, promoted root elongation, and accelerated flowering, with flowering occurring approximately four days earlier than in wild-type plants. Changes in development were accompanied by increased starch accumulation, elevated amylose levels, and a higher abundance of enlarged starch granules within chloroplasts. Under drought and PEG-induced osmotic stress, transgenic plants maintained improved growth performance and recovery capacity, together with greater proline accumulation and chlorophyll retention. These physiological advantages coincided with more rapid starch utilization and clear rises in transcripts for proline synthesis enzymes (AtP5CS1, AtP5CS2) and starch-degrading proteins (AtBAM1, AtBAM3, AtDPE1). Collectively, these findings suggest that ZmGBSS1 not only regulates starch biosynthesis but also plays a crucial role in coordinating plant development and drought stress responses, highlighting its potential for improving stress tolerance through metabolic regulation. Full article

Nitrogen is an essential element for plant growth, and low nitrogen stress significantly restricts crop yield. Therefore, cultivating crop varieties that are tolerant to low nitrogen is crucial for agricultural production. The AT-hook motif nuclear localization protein (AHL) family is vital for plant stress resistance. To investigate the potential regulatory mechanisms of the AHL family in maize under low nitrogen stress, 35 ZmAHL genes were identified from the maize genome using bioinformatics methods. The results indicated that these genes encode proteins with lengths ranging from 203 to 573 amino acids, with relative molecular weights between 20.68 and 59.68 kDa, and they are unevenly distributed across 10 chromosomes. Most proteins encoded by these genes are alkaline hydrophilic proteins, primarily localized in the nucleus. Family expansion occurred through tandem and fragment repeats, which exhibited evolutionary conservation with rice homologous genes. Transcriptome analysis revealed that the majority of ZmAHL genes in drought-tolerant maize inbred lines were significantly up-regulated under drought and low nitrogen stress, with the ZmAHL10 gene displaying the most pronounced response to low nitrogen conditions. Experiments involving transgenic Arabidopsis thaliana further confirmed that the growth status, nitrogen uptake, and photosynthetic pigment content of ZmAHL10 overexpression strains under low nitrogen conditions were superior to those of the wild type, while the mutant exhibited significant growth inhibition. Overall, this study delineated the fundamental characteristics of the maize ZmAHL gene family and established that ZmAHL10 enhances low nitrogen tolerance in plants by improving nitrogen absorption capacity and maintaining the stability of the photosynthetic system. This research provides candidate genes and a theoretical foundation for the molecular breeding of maize with enhanced low nitrogen tolerance. Full article

The artificially modified Bacillus thuringiensis (Bt) protein can target lepidopteran pests, and planting genetically modified crops with insect-resistant traits is environmentally friendly. However, it is still uncertain whether the exogenous insect-resistant proteins in genetically modified crops will affect the soil rhizosphere microorganisms. This study utilized 16S rDNA sequencing technology to analyze the rhizosphere soil of insect-resistant genetically modified corn LD05 and its control variety Zheng58 at five developmental stages: before sowing, seedling stage, jointing stage, silk emergence stage, and maturity stage. Each sample was taken with six biological replicates, resulting in a total of 60 sequencing samples, with an average of 4368 OTUs obtained per sample. Both alpha and beta analyses showed that LD05 and Zheng58 did not have a significant impact on the soil rhizosphere microbial community. The developmental stage rather than the variety was the main factor causing differences in the bacterial community. Overall, there was no significant difference in the bacterial diversity between the insect-resistant genetically modified corn LD05 and its control variety Zheng58. The results provide useful information for understanding the impact of genetically modified crops on soil microbial communities and also provide a theoretical basis for the safety evaluation of LD05. Full article

Saline–alkali land represents an important reserve of arable resources in China, and exploiting its agricultural potential is crucial for ensuring food security. In maize (Zea mays L.), which is moderately sensitive to salt stress, proline serves as a key osmoprotectant, and Δ¹-pyrroline-5-carboxylate synthetase (P5CS), the rate-limiting enzyme in its biosynthesis, plays a vital role in plant stress responses. In this study, the maize ZmP5CS gene family was systematically identified and characterized through comprehensive bioinformatics analyses. Four ZmP5CS homologs were identified, most of which were predicted to localize to chloroplasts. Phylogenetic analysis classified these genes into four major clades. Among them, ZmP5CS4 (GRMZM2G028535) expression was significantly upregulated under salt stress. Association analysis using a natural population of 278 inbred lines revealed that nine SNPs significantly associated with relative P5CS enzyme activity were located within ZmP5CS4. Haplotype analysis further identified a superior haplotype, HapA, carried by 14 inbred lines. Under salt stress, lines carried by HapA exhibited higher P5CS enzyme activity, greater proline accumulation, lower standard evaluation scores, and slightly enhanced salt tolerance compared to lines carried by HapB. Functional validation via transgenic approaches demonstrated that ZmP5CS4 overexpression significantly increased proline content and plant survival under salt stress, whereas knockout of this gene led to heightened salt sensitivity. Collectively, this study elucidates the structure and function of the maize ZmP5CS gene family, establishes the critical role of ZmP5CS4 in the salt stress response, and provides both a theoretical foundation and a candidate gene resource for improving salt tolerance in maize breeding programs. Full article

Cadmium (Cd) contamination severely threatens crop productivity and food safety, particularly in maize (Zea mays L.), which exhibits relatively high capacities for metal uptake and translocation. Metal tolerance proteins (MTPs) play essential roles in metal homeostasis and detoxification; however, the functions of maize MTP under Cd stress remain poorly understood. In this study, a comprehensive expression analysis of the maize MTP gene family revealed that two Zn-CDF members, ZmMTP1-1 and ZmMTP1-2, displayed the strongest and most consistent transcriptional induction in response to Cd stress, especially in roots. Phylogenetic and structural analyses confirmed that both genes are closely related to MTP1 homologs from other plant species, while exhibiting distinct gene structures and regulatory features. Functional characterization in transgenic Arabidopsis thaliana demonstrated that overexpression of ZmMTP1-1 or ZmMTP1-2 significantly enhanced tolerance to Cd and Zn stress, as reflected by improved seed germination, root growth, survival, and biomass accumulation. Enhanced metal tolerance was associated with elevated antioxidant enzyme activities, reduced oxidative damage, and coordinated upregulation of endogenous metal transporter genes. Moreover, heterologous expression of ZmMTP1-1 in yeast further supported its conserved role in Cd tolerance. Collectively, these findings indicate that ZmMTP1-1 and ZmMTP1-2 contribute to Cd detoxification through coordinated metal transport and stress-response pathways, providing potential genetic resources for improving heavy metal tolerance in maize. Full article

Plant cell walls provide structural integrity and defense against biotic and abiotic stresses. In rice (Oryza sativa), xylan is the major hemicellulose, and β-xylosidase hydrolyzes xylan by removing xylose residues from non-reducing ends. We analyzed a transgenic rice line (OsXylGH3-1-FOX) that constitutively overexpresses a GH3-family β-xylosidase (Os03g0749100) under the maize ubiquitin promoter. Following inoculation with M. oryzae, OsXylGH3-1-FOX leaves exhibited increased lesion numbers and disease indices, indicating reduced resistance, whereas leaf sheaths showed fewer fungal penetrations, suggesting enhanced resistance. To investigate these organ-specific responses, we quantified cell wall components. In leaves, xylose and arabinose decreased by ~33%, and galacturonic acid (pectin) by ~50%. In leaf sheaths, xylose and arabinose were unchanged, while galacturonic acid and cellulose increased by ~50% and ~70%, respectively. Histochemical staining confirmed reduced pectin in leaves and stronger, organized cellulose and pectin in leaf sheaths. These findings suggest that decreased pectin weakens cell adhesion, facilitating pathogen ingress in leaves, whereas increased pectin and cellulose reinforce wall integrity in leaf sheaths. Thus, pectin and cellulose abundance strongly correlate with organ-specific blast resistance, while hemicellulose plays a secondary role. Full article

Exogenous protein degradation dynamics during transgenic maize straw degradation in soil and the mechanisms underlying soil microbial community construction remain unclear. Applying null-model analysis to determine these mechanisms is important for assessing transgenic crop straw return-to-field-related impacts on dynamic soil quality and microbial ecological function changes. A laboratory leaf degradation burial simulation was conducted to establish an exogenous protein Cry1A.401 soil degradation model and clarify its behaviors. Coupled Illumina MiSeq 16S rDNA sequencing–soil physicochemical factor analysis was used to evaluate soil microbial community characteristic and diversity changes during leaf degradation and explore soil microbial community construction mechanisms and driving factors. The results revealed that exogenous protein Cry1A.401 released from transgenic insect-resistant maize leaves exhibited consistent degradation characteristics, decreasing rapidly at the initial stage but slowly at the middle/late stages. The diversity levels within/between soil microbial community groups did not significantly differ. Coexistence was the dominant interaction type among soil microbial communities. Community assembly occurred stochastically and was limited primarily by diffusion. Insights into the putative mechanistic links among Bacillus thuringiensis (Bt) proteins, soil properties, and microorganisms are provided. Our understanding of the ecological impacts of exogenous Bt proteins released into soil via leaves on soil ecosystems was enhanced. Full article

In the process of maize production, extreme meteorological conditions such as drought and high temperature are often the main environmental stress factors affecting pollination efficiency. Previous studies have shown that, under adversity, the germination rate of pollen grains on the filaments of female spikes directly affects the success rate of reproduction and ultimately determines the grain yield. This study focuses on a cysteine protease named ZmPCP. The expression of this protease in maize pollen is significantly higher than in other tissues, and its specific function has not been clearly defined. Its localization in the cell membrane or apoplast was further confirmed by transient transfection experiments and plasmolysis. The interaction between ZmPCP and ZmSNAP33 was verified by yeast two-hybrid technology and a GST pull-down experiment, indicating that ZmPCP may affect pollen germination and stress resistance by regulating vesicle transport. Secondly, by analyzing the pollen germination rate of maize inbred lines B104, ZmPCP-KO and ZmPCP-OE transgenic maize plants, we found that ZmPCP overexpression could significantly enhance pollen viability and pollen tube growth under drought stress. After 1 h of short-term drying treatment, the pollen germination rate of the ZmPCP-OE line was maintained at 44%, which was significantly higher than that of the other lines. In addition, the observation of pollen tube growth showed that ZmPCP overexpression could promote the extension of pollen tubes in the filament. Moreover, a transcriptome sequencing analysis revealed the regulatory effects of ZmPCP on pollen in multiple biological processes, including stress response, carbohydrate metabolism, growth and development, cell wall material metabolism, signal transduction, etc. The involved pathways of these differential genes indicate that ZmPCP enhances pollen drought tolerance and promotes pollen tube growth through a “metabolism signal structure”. In the germination experiment on the seventh day, the germination rate of ZmPCP-OE maize seeds was the lowest, indicating that its overexpression inhibited seed germination. At the same time, ZmPCP-overexpressing Arabidopsis showed a significant advantage in taproot growth under high-concentration ABA stress. ZmPCP provides an important theoretical basis for regulating the pollination process and improving the pollination efficiency of maize varieties through interaction with ZmSNAP33. Full article

To evaluate the comprehensive ecological risks associated with transgenic plant residues, this study examined their impact on Eisenia fetida and their endogenous microorganisms. The results indicated that transgenic plant residues did not influence the survival or weight of E. fetida, but they significantly altered the microbial community structure at specific time points. Specifically, the diversity and structure of the fungal community exhibited significant changes on the 14th and 28th days after treatment. In contrast, the bacterial response was delayed, with 22 biomarkers, including Caproiciproducens, Lachnoclostridium, and Enterococcus, being specifically enriched on the 21st day. This study confirmed that transgenic plant residues can temporally reshape the microecology within E. fetida. The practical significance of this research lies in highlighting the importance of incorporating the microbiome into safety assessment frameworks, thereby providing a scientific foundation for developing more forward-looking ecological risk assessment standards. Full article

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. Full article

The fall armyworm (Spodoptera frugiperda) is a globally invasive pest that threatens the yield of maize and other grain crops. Transgenic insect-resistant maize offers an effective management strategy; however, rigorous evaluation of resistance to it depends on rapid and standardized infestation protocols. We developed and benchmarked laboratory, screenhouse, and field methods for rapid resistance assessment using 1–4-day-old larvae (L1–L4) and maize whorl leaves, silks, and kernels as feeding substrates. In laboratory bioassays, five L2 on each leaf or silk treatment enabled resistance assessment on day 2 post-infestation, whereas two L1 per treatment on kernels supported evaluation on day 3. In screenhouse trials, infesting each plant with twenty L2 allowed reliable leaf-injury ratings on day 10. In field trials, thirty L3 per plant with assessment on day 12 produced better outcomes. Together, these protocols provide a detailed and adaptable framework that reduces costs, shortens evaluation timelines, and offers practical guidance for resistance assessment of transgenic maize across controlled and open environments. Full article

Leaf color mutants are commonly characterized by altered chlorophyll content and aberrant chloroplast development, making them valuable models for investigating photosynthetic mechanisms and chloroplast biogenesis. In this study, an albino mutant was isolated from a population of transgenic maize breeding lines. Genetic analysis indicated that the mutant phenotype is inherited in a Mendelian manner and is controlled by a single nuclear locus. This was supported by a χ² test performed on the T₂ generation, which confirmed a segregation ratio consistent with 3:1 (176:68, χ² = 1.07 < χ²_0.05 = 3.84, p > 0.05). Microscopic examination revealed the absence of normally developed chloroplasts in mutant cells. Further expression analysis of chloroplast genes via Northern blotting and quantitative real-time PCR (qRT-PCR) suggested that the mutation impairs the regulation of plastid-encoded polymerase (PEP)-dependent chloroplast gene expression. Notably, PCR-based co-segregation analysis indicated that the mutant phenotype is associated with the entire inserted vector sequence, rather than a point mutation or a small genomic deletion. In conclusion, this paper reports the isolation and phenotypic characterization of an etiolated mutant from a transgenic maize breeding population, including comparative ultrastructural analysis of chloroplasts, co-segregation validation, and chloroplast gene expression profiling. These results enhance our understanding of the physiological and molecular mechanisms underlying chlorophyll-deficient mutations in plants. Full article

The global population growth has driven the widespread adoption of genetically modified crops, with Bt maize, due to its insect resistance, becoming the second most widely planted GM crop. However, studies on the effects of continuous Bt maize cultivation on soil ecosystems are limited, and there is an urgent need to assess its ecological safety at the regional scale. To evaluate the potential effects of continuous cultivation of transgenic Bt maize on the soil ecosystem, a five-season continuous planting experiment was conducted using two Bt maize varieties (5422Bt1 and 5422CBCL) and their near-isogenic conventional maize (5422). After five consecutive planting seasons, bulk soil and rhizosphere soil were collected. The main nutrient contents of the bulk soil were measured, and high-throughput sequencing was employed to analyze microbial diversity and community composition in both soil types. The results showed that, compared with the near-isogenic conventional maize 5422, continuous planting of Bt maize varieties 5422Bt1 and 5422CBCL did not affect the contents of organic matter, total nitrogen, total phosphorus, total potassium, alkaline hydrolyzable nitrogen, available phosphorus, or available potassium in bulk soil. Regarding the microbial communities in bulk soil, there were no significant differences in the α-diversity indices of bacteria and fungi after five consecutive seasons of Bt maize cultivation, compared with soils planted with the near-isogenic conventional maize 5422. Proteobacteria and Ascomycota were the dominant phyla of bacteria and fungi, respectively. Principal coordinate analysis (PCoA) and redundancy analysis (RDA) revealed that the structure of microbial communities in bulk soil was primarily influenced by factors such as OM, TP, TN and AN, whereas the Bt maize varieties had no significant effect on the overall community structure. Regarding the rhizosphere soil microbial communities, compared with the near-isogenic conventional maize 5422, the evenness of the bacterial community in the rhizosphere soil of Bt maize decreased, leading to a reduction in overall diversity, whereas species richness showed no significant change. This change in diversity patterns further contributed to the restructuring of the rhizosphere soil microbial community. In contrast, the fungal community showed no significant differences among treatments, and its community structure remained relatively stable. Proteobacteria and Ascomycota were the dominant phyla of bacteria and fungi, respectively. Principal coordinate analysis (PCoA) indicated that continuous cultivation of Bt maize for five seasons had no significant effect on the structure of either bacterial or fungal communities in the rhizosphere soil. In summary, continuous cultivation of Bt maize did not lead to significant changes in soil nutrient contents or microbial community structures, providing a data foundation and theoretical basis for the scientific evaluation of the environmental safety of transgenic maize in agricultural ecosystems. Full article

Phospholipase D (PLD) genes play key roles in plant abiotic stress responses, but the systematic identification of the maize (Zea mays) PLD family and its cold tolerance mechanism remain unclear. Using 26 maize genomes (pangenome), we identified 21 ZmPLD members via Hidden Markov Model (HMM) search (Pfam domain PF00614), including five private genes—avoiding gene omission from single reference genomes. Phylogenetic analysis showed ZmPLD conservation with Arabidopsis and rice PLDs; Ka/Ks analysis revealed most ZmPLDs under purifying selection, while three genes (including ZmPLD15) had positive selection signals, suggesting roles in maize adaptive domestication. For ZmPLD15, five shared structural variations (SVs) were found in its promoter; some contained ERF/bHLH binding sites, and SVs in Region1/5 significantly regulated ZmPLD15 expression. Protein structure prediction and molecular docking showed conserved ZmPLD15 structure and substrate (1,2-diacyl-sn-glycero-3-phosphocholine) binding energy across germplasms. Transgenic maize (B73 background) overexpressing ZmPLD15 was generated. Cold stress (8–10 °C, 6 h) and recovery (24 h) on three-leaf seedlings showed transgenic plants had better leaf cell integrity than wild type (WT). Transgenic plants retained 45.8% net photosynthetic rate (Pn), 47.9% stomatal conductance (Gs), and 55.8% transpiration rate (Tr) versus 7.6%, 21.3%, 13.8% in WT; intercellular CO₂ concentration (Ci) was maintained properly. This confirms ZmPLD15 enhances maize cold tolerance by protecting photosynthetic systems, providing a framework for ZmPLD research and a key gene for cold-tolerant maize breeding. Full article

The commercialization of genetically modified (GM) maize and soybean is advancing, with strip intercropping emerging as a promising model to enhance crop yields and resource efficiency. However, the impact of this system on target pests remains unclear. To address this, we evaluated eight different planting patterns (four different monocultures and four different strip intercropping integrations) of insect-resistant GM maize (‘RF88’) and soybean (CAL16) events and their non-transgenic parental lines (Xianyu 335 maize and Tianlong No. 1 soybean) in the Huang-Huai-Hai planting area from 2023 to 2025. Our results identified Helicoverpa armigera and Spodoptera exigua as the dominant pests on maize and soybean, respectively. We found that the GM trait significantly reduced the population density and plant damage caused by these pests. Strip intercropping also provided significant suppression across both crop lines. Furthermore, the integration of strip intercropping and the GM trait resulted in the most effective pest control. This study provides valuable insights for the top-level design and industrial layout of GM crop commercialization and contributes to promoting its safe application and sustainable pest management. Full article