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PubMed2026

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.

AP2/ERF transcription factors↗
PubMed1978

Seed germination as a thermobiological problem.

Thermal effects on seed germination are considered through the changes brought about by temperature in the germination capacity, in the germination rate, and in the distribution of the relative frequency of germination along the incubation times. A number of questions of general thermobiological interest are thus raised, entailing the need of an analysis of the temperature dependence of the seed germination rate. A treatment of these rates by the activation-energy approach cannot be general, for their Arrhenius plots are not always linear. Moreover, it is shown that any process displaying a temperature optimum (as happens in the germination of most seed species) cannot follow one of the fundamental tenets of the collision rate theory. The need of a theoretical treatment stressing the essential role of the partition of energy within the seed system has led to an anlysis using the absolute reaction rate theory. New experimental prospects for the physiology of seed germination are thus raised, concerning the meaning of the temperature cardinal points, the growth pattern of the embryo in germinating seeds, the dual effect of protein thermodenaturation, the effects of high hydrostatic pressures, and a whole pharmacological line of work. The cybernetic counterpart of the thermodynamic view of seed germination appears in the study of the distribution of the relative frequency of germination along the isothermal incubation time. In some species of seeds the thermal communication between the environment and the seed growth effector can be shown to proceed by molecular collisions at all germination isotherms. In the seeds of Dolichos biflorus this communication through random thermal noise prevails only at temperatures close to both extreme limits of germination. Both in this species and in Calotropis procera there is a temperature range (encompassing the optimum) within which a temperature signal is superimposed upon the gaussian noise. An interpretation is proposed according to which the temperature signal is transduced in a protein-conformation code.

Protein Denaturation↗
PubMed2026

Positive feedback loop between RAF12 and ABI5 reinforces ABA-mediated suppression of Arabidopsis seed germination.

ABA-INSENSITIVE 5 (ABI5) is a key transcriptional regulator mediating abscisic acid (ABA)-induced suppression of seed germination. However, the downstream regulatory network through which ABI5 exerts its function remains incompletely understood. Here, by integrating ChIP-seq and RNA-seq analyses, we identify RAF12, a member of the B2 Raf-like kinase subfamily, as a direct transcriptional target of ABI5. ABI5 binds to the RAF12 promoter and activates its expression. Loss-of-function raf12 mutants exhibit reduced sensitivity to ABA during seed germination, suggesting a negative regulatory role for RAF12 in this process. Conversely, RAF12 interacts with and phosphorylates ABI5, thereby enhancing its transcriptional activity. Further analysis showed that RAF12 regulates its own kinase activity through autophosphorylation. Mutations at its phosphorylation sites significantly weaken its ability to enhance ABI5's transcriptional activity. Together, these findings uncover a positive feedback loop wherein ABI5 transcriptionally activates RAF12, which in turn reinforces ABI5 activity through phosphorylation. This module may function in parallel with the canonical SnRK2s-ABI5-mediated ABA signaling cascade, offering new mechanistic insights into the fine-tuning of ABA responses during seed germination.

Arabidopsis↗
PubMed1975

Toxicological implications of pesticides: their toxic effects on seeds of food plants.

Pesticides are widely used for the protection of economic crops from a variety of noxious pests. The repeated and indiscriminate uses and the extreme stability of certain pesticides have led to their accumulation in plants, animals, soils and sediments, thus effecting widespread contamination of the environment. Soil contaminants are especially serious because they can inhibit or impair the seed germination of our food and feed crops. Seeds can come in close contact with pesticides through processes such as prematurity application, fumigation, seed dressings, and seed treatments. Several reports have indicated the toxic effects of pesticides on seed germination. Possible mechanisms of the toxic action on pesticides during the germination of seeds have been discussed with emphasis on biochemical, histological, and cytological alterations. Bioassay procedures employing seed germination as a smiple, feasible, economical, time-saving indicator of toxicity have been described briefly. Attention is then drawn to the possible potential health hazards arising from the presence of pesticidal chemicals in food plants since the toxicological implications of long term exposure to pesticides are often more far-reaching.

Animals↗
PubMed1977

Introduction. Membrane transport of peptides.

Carrier-mediated membrane transport of small peptides is now realized to be a process of wide biological distribution, occurring not only in the small intestine and elsewhere in the animal body but also in bacteria, yeast, the mould Neurospora crassa, and probably in higher plants during the germination of seeds. The important features of peptide transport are outlined, and possible relationships between peptide transport and hydrolysis are discussed. Peptide transport is a stereochemically specific active process, and is independent of the transport of free amino acids. It is frequently, though not always, more rapid than the transport of amino acids. In the intestine, it is probably limited to dipeptides and tripeptides, but certain other animal cells and bacteria can take up larger peptides of seven or more amino acid residues. The ability to take up small peptides on a large scale is nutritionally important in some microorganisms, and might be of nutritional importance to the intact animal and to animal cells in culture. In the absorptive cells of the small intestine, and in Escherichia coli, peptide transport into the cells is followed by intracellular hydrolysis; transport and hydrolysis are quite distinct processes. Whether hydrolysis and amino acid transport can be coupled processes, or whether peptide transport and hydrolysis are different aspects of the same process, remains to be seen. This question is one of those where a close integration of studies of peptide transport with those of peptide hydrolysis should be particularly helpful.

Bacteria↗
PubMed1978

Structural transformation and modulation of succinic dehydrogenase activity in the mitochondria of germinating seeds.

Ultrastructural transformation of mitochondria in the cotyledons of dry and germinating seeds of Vigna sinensis from the 'orthodox' to 'condensed' forms is coupled with an increasing rise in the specific activity of succinic dehydrogenase (SDH). Apparently, the transformation of mitochondria to the 'condensed' form associated with the utilization of substrate which is reflected in the rise in enzyme activity. During the process of germination, the mitochondria of the cotyledonary cells undergo three different phases namely, (1) activation phase, (2) preparatory phase, and (3) multiplication phase.

Mitochondria↗
PubMed2026

From dormancy to germination: Transcriptome analysis reveals the potential involvement of heat shock proteins in gibberellin-induced seed dormancy release in Solanum torvum.

Solanum torvum, a superior vegetable grafting rootstock and medicinal Solanaceae plant, exhibits strong seed dormancy, which limits its commercial cultivation. Among various strategies explored to improve the germination rate of S. torvum, exogenous application of gibberellin (GA) has been shown to be effective. In this study, a GA concentration of 2.5 mM was established as the optimal for breaking dormancy in S. torvum seeds. Transcriptome analysis of dry, water-soaked, GA-soaked, and GA-induced germinated seeds was conducted to investigate the molecular mechanism of GA-mediated dormancy release. During the soaking period, GA application significantly induced transcriptome changes in processes including protein processing, translation, and peptide biosynthesis. Concurrently, GA treatment promoted plant hormone signal transduction, enhanced DNA-binding transcription factor activity, and activated monocarboxylic acid biosynthetic process, all of which facilitated seed water absorption. Furthermore, the differentially expressed genes (DEGs) induced by GA during soaking primarily functioned in signal transduction or activation. While most of these DEGs returned to their pre-treatment expression levels before subsequent recovery, a subset persisted until seed germination. During radicle protrusion, the persistent DEGs were associated with energy metabolism and cell structure establishment. Notably, heat shock protein (HSP) genes showed dynamic expression across all stages (soaking, germination, and radicle penetration). Furthermore, by adjusting germination conditions, temperature was confirmed to be a necessary but not sufficient condition for GA-induced S. torvum seed germination. However, functional validation (e.g., using HSP inhibitors or genetic approaches) is still required to confirm the causal role of HSPs. Collectively, these findings not only clarify the molecular basis of GA-regulated seed dormancy breaking in S. torvum but also provide practical guidance for optimizing its commercial propagation protocols.

Gibberellins↗
PubMed2026

Disruption of the ubiquitin-mediated proteolysis pathway: a study of seed aging in Saposhnikovia divaricata caused by UBC1 gene family suppression.

BACKGROUND: Saposhnikovia divaricata (Turcz.) Schischk. is a perennial herb whose seed aging during storage significantly reduces germination rates, limiting industrial-scale production. Reactive oxygen species (ROS)-induced oxidative damage is a key driver of seed aging, but the underlying mechanisms in Saposhnikovia divaricata remain unclear. RESULTS: Suppression of the UBC1 gene family reduces the activity of ubiquitin-conjugating enzymes, leading to dysfunction of the ubiquitin-mediated proteolysis pathway, which in turn decreases protein degradation efficiency and causes the accumulation of damaged proteins. Transcriptome analysis revealed predominant downregulation of genes crucial for seed physiological maintenance. By the fourth year of storage, germination dropped sharply to 30.67%, accompanied by embryo cavitation. Downregulation of ribosome pathway genes hindered ribosome assembly and protein synthesis, while suppression of endoplasmic reticulum protein processing genes led to unfolded/misfolded protein accumulation and intensified cellular stress, accelerating aging. Proteomic analysis showed increased total differential and antioxidant-related proteins. ROS content fluctuated with storage time: peroxyl radicals peaked in year two (5.68 RFU/mg), whereas hydroxyl radicals and hydrogen peroxide were highest in year four (0.0655 pg/mL and 0.0946 pg/mL, respectively), with significant differences across periods. Elevated membrane-related proteins, increased electrical conductivity, and malondialdehyde content (maximum 54.30 nmol/g at year four) confirmed oxidative membrane damage. ROS-induced stress promotes protein misfolding, and reduced UBC1 expression is associated with impaired clearance of misfolded proteins by the ubiquitin-mediated proteolysis pathway. CONCLUSIONS: This study provides the first integrated transcriptomic and proteomic insight into UBC1 deficiency-mediated seed aging in Saposhnikovia divaricata. The findings enhance molecular understanding of seed aging and offer new directions for improving seed storage and viability.

Ubiquitin-Conjugating Enzymes↗
PubMed1978

[Influence of b and giberellic acid on the transformation of lipids in glucids during the germination of sunflower seeds (author's transl)].

The transformation of total lipids in carbohydrates and the evolution of the fatty acids, constituents of these lipids, during the germination of sunflower seeds, soaked previously in B and giberellic acid solutions, was studied. An inverse relationship between the total content in fatty acids and sugars of the blank (H20) and AG3 treatments was found. However, in the whole germinative process, the B and B + AG3 treatments changed strongly the carbohydrates metabolism and no significant differences of those constituents was observed. The content in fatty acids in the two last treatments showed a great stability and the percentage of these components remained fixed in all the treatments.

Boronic Acids↗
PubMed1977

[Partial purification and characterization of protease A of germinating vetch seeds, hydrolyzing native reserve proteins].

Protease A is 870-fold purified by means of isoelectric precipitation, DEAE-cellulose chromatography and gel filtration through Sephadex G-50, the yield of the enzyme being 28%. The purified preparation is free of contaminant proteolytic activity and is almost homogenous chromatographically, but it produces a complex pattern under electrophoresis in 30% polyacrylamide gel, which is probably due to enzyme autolysis. As evidenced from the effect of protease A on A and B chains of insulin, the enzyme has a wide substrate specificity. It hydrolyses native vetch legumin and vicilin up to peptides having on average 9 and 16 amino acid residues respectively. No free amino acids were found in hydrolysates of both vetch proteins. Thus, protease A is an endopeptidase, which probably plays the main role in the process of reserve proteins degradation.

Fabaceae↗
PubMed1977

Decline in ribonucleic acid and protein synthesis with loss of viability during the early hours of imbibition of rye (Secale cereale L.) embryos.

A decline in protein synthesis and slow germination accompanies loss of viability in embryos of rye (Secale cereale L.) grains. Associated with this, incorporation of precursors into all the major classes of RNA is decreased and the processing of precursor rRNA to 25S and 18S RNA is retarded. Embryos that just reach 0% viability still synthesize some low-molecular-weight non-nucleolar material, although they do not synthesize protein. It is suggested that early-synthesized RNA could play a major part in determining the extent of protein synthesis at early germination, and thereby regulate the rate at which germination can proceed.

Plant Proteins↗
PubMed2025

Unveiling the mechanism of micro-and-nano plastic phytotoxicity on terrestrial plants: A comprehensive review of omics approaches.

Micro-and-nano plastics (MNPs) are pervasive in terrestrial ecosystems and represent an increasing threat to plant health; however, the mechanisms underlying their phytotoxicity remain inadequately understood. MNPs can infiltrate plants through roots or leaves, causing a range of toxic effects, including inhibiting water and nutrient uptake, reducing seed germination rates, and impeding photosynthesis, resulting in oxidative damage within the plant system. The effects of MNPs are complex and influenced by various factors including size, shape, functional groups, and concentration. Recent advancements in omics technologies such as proteomics, metabolomics, transcriptomics, and microbiomics, coupled with emerging technologies like 4D omics, phenomics, spatial transcriptomics, and single-cell omics, offer unprecedented insight into the physiological, molecular, and cellular responses of terrestrial plants to MNPs exposure. This literature review synthesizes current findings regarding MNPs-induced phytotoxicity, emphasizing alterations in gene expression, protein synthesis, metabolic pathways, and physiological disruptions as revealed through omics analyses. We summarize how MNPs interact with plant cellular structures, disrupt metabolic processes, and induce oxidative stress, ultimately affecting plant growth and productivity. Furthermore, we have identified critical knowledge gaps and proposed future research directions, highlighting the necessity for integrative omics studies to elucidate the complex pathways of MNPs toxicity in terrestrial plants. In conclusion, this review underscores the potential of omics approaches to elucidate the mechanisms of MNPs-phytotoxicity and to develop strategies for mitigating the environmental impact of MNPs on plant health.

Plants↗
PubMed1979

Deoxyribonucleotide synthesis and DNA polymerase activity in plant cells (Vicia faba and Glycine max).

Enzymes of deoxyribonucleotide and DNA biosynthesis, which are little known in plants, were studied in root tips of germinating broad beans (Vicia faba) and in fast-growing cultures of soybean cells (Glycine max). The plant cells contain a ribonucleoside 5'-diphosphate reductase which is detected in vitro only during a limited period of growth, viz. 30--32 h after inhibition of Vicia seeds, and between the second and third day after inoculation of soybean cultures. In both species ribonucleotide reductase activity precedes maximum DNA synthesis. The reductases could be precipitated with ammonium sulfate but were not purified further due to the extremely low enzyme content of the plant extracts. Therefore the reductive pathway of deoxyribotide formation was also established in Vicia root tips by efficient labeling of the plant DNA with a ribonucleoside, [5-3H]cytidine, which reaches a maximum at the same time as the reductase activity measured in vitro. Cycloheximide inhibits this process, indicating the need for de novo enzyme induction. In contrast, DNA polymerase is present in the tissue throughout the entire development and rises only 2-fold in activity during the S phase. The soluble polymerases were partially characterized in both legume species and were found very similar to the DNA polymerase of pea seedlings. Ribonucleotide reductase is more likely a limiting component of DNA formation during the plant cell cycle than DNA polymerase.

DNA↗