Search Results (471)

Clove (Syzygium aromaticum (L.) Merr. & L.M. Perry) essential oil (EO)-based nanoemulsions may have a promising future in eco-friendly herbicide development. Clove EO was found to have a high eugenol content of 87.27%. Organic-solvent-free nanoemulsions using clove EO as a bioactive ingredient were fabricated using ultrasonication and microfluidization emulsification methods. Fourier-transform infrared spectroscopy confirmed that both emulsification methods did not affect the EO components. The droplet size of optimized nanoemulsions was determined using dynamic light scattering. The smallest size of 66.9 nm was obtained by microfluidization at 20,000 psi and eight passes. Additionally, the smallest droplet size for a sonicated nanoemulsion was 103.9 nm, obtained by ultrasonication at 20% for 6 min. Transmission electron microscopy confirmed the droplet sizes of both optimized nanoemulsions. In a storage test, both optimized nanoemulsions were stored at 4 °C for at least four weeks. Finally, both nanoemulsions were evaluated on pre-emergence herbicidal activities against Echinochloa crus-galli. The results showed that both nanoemulsions inhibited E. crus-galli germination and seedling growth, and additionally, inhibited seed imbibition and α-amylase activity. Micro-morphological and ultrastructural analysis was observed using a scanning electron microscope and an energy dispersive X-ray spectrometer (SEM-EDS). SEM-EDS micrographs of the treated seeds showed that the seed structure was damaged, especially the endosperm, leading to the inhibition of seed germination. Full article

Common wheat (Triticum aestivum L.) is a staple food crop for humans, yet it primarily accumulates the non-provitamin A carotenoid lutein and exhibits limited natural variation in provitamin A β-carotene among its various accessions. This characteristic necessitates the development of alternative strategies for provitamin A biofortification. To address this challenge, we targeted key control points in the carotenoid biosynthetic pathway using the CRISPR-Cas9 system in a wheat cultivar Fielder. Specifically, we knocked out the gene encoding lycopene ε-cyclase (LCYE), an enzyme that acts as a gatekeeper opposing the production of β-branch carotenoids. Biochemical analysis of homozygous transgene-free mutant endosperms at 20 days post-anthesis (DPA) revealed marked metabolic rerouting of carotenoid biosynthesis, characterized by differential, line-specific accumulation patterns. Provitamin A carotenoids—specifically β-carotene—increased by 26.1–34.5% relative to wild-type controls, concomitant with elevated 22.9–125.4% for zeaxanthin, 41.6–73.9% for violaxanthin, and 26.2–186.5% for antheraxanthin. However, these gains were offset by drastic lutein reduction in lines 1–4 and 5–1. Consequently, total carotenoid levels displayed non-uniform responses, with line 5–1 exhibiting a modest decrease relative to wild-type. Moreover, the mutant lines exhibited elevated levels of amylose and soluble sugar, and the seed coats and endosperms of the triple homozygous transgene-free mutant lines exhibited an orange-yellow hue. In conclusion, we have successfully developed novel carotenoids biofortified wheat lines through a gene-editing approach. This study demonstrates targeted redirection of carotenoid biosynthesis via gene editing as an effective strategy to enhance the nutritional value of commercial wheat and mitigate micronutrient deficiencies in modern food systems. Full article

Background: Starch accumulation contributes substantially to maize grain yield and quality. Starch synthase III (SSIII) is a key component of the starch biosynthetic enzyme complex. However, its regulatory role in starch accumulation in maize endosperm remains incompletely understood. Methods: The du1-2018 mutant arose spontaneously during a conventional maize breeding program. Phenotypic characterization, storage compound contents, and starch structure were compared between the mutant and wild-type lines. BSA-seq, genetic linkage analysis, and transcriptomic analysis were employed to identify the candidate gene responsible for the mutant phenotype. Transcriptome sequencing was performed on developing kernels to evaluate the genome-wide effects of the du1-2018 mutation. Results: The du1-2018 mutant exhibited dull, glassy, and mildly shrunken kernels, with decreased starch levels and elevated soluble sugar and protein contents. The du1-2018 mutation disrupted starch accumulation, resulting in smaller, irregularly shaped starch granules and significant changes in starch composition and fine structure. This mutation was identified as a severe loss-of-function allele of the dull1 (du1) gene, evidenced by almost undetectable Du1 transcripts in developing kernels. Notably, transcriptomic analysis revealed that a substantial proportion of differentially expressed genes (DEGs) were involved in amino acid and protein metabolism. Conclusions: The novel du1 allelic variant, du1-2018, disrupts starch biosynthesis in maize endosperm, leading to reduced starch accumulation, altered starch structure, and transcriptional changes in nitrogen-related metabolic pathways. Our results provide new insights into the regulatory mechanisms underlying SSIII function in starch synthesis and endosperm development, and suggest potential links to carbon/nitrogen balance, with implications for future genetic improvement of maize grain quality. Full article

MADS-box transcription factors are key regulators of plant development and environmental responses. Here, we performed an integrated phylogenomic and expression analysis of the MADS-box gene family in Capsicum annuum, identifying 97 members that fall into 52 Type I and 45 Type II genes. Comparative phylogeny, exon–intron organization, conserved motifs, and chromosomal mapping allowed classification into 15 subfamilies. Gene duplication analysis revealed that segmental duplication has been a major driver of family expansion. Expression profiling across multiple tissues, together with promoter cis-element prediction and stress-responsive transcriptome data, demonstrated that Type II genes exhibit broad and dynamic expression patterns, particularly under ABA treatment and temperature stress. A key finding of this study is the complete absence of the Mβ lineage, a Type I subfamily typically associated with gametophyte and endosperm development in other angiosperms. No Mβ-like sequences were detected in the pepper genome, and Type I genes overall showed extremely low expression, suggesting that the Mβ lineage has undergone lineage-specific evolutionary loss and that its functions may be compensated by other Type I members or by expanded Type II regulatory modules. Together, this study provides the first evidence for the evolutionary disappearance of the Mβ subfamily in Capsicum and offers a comprehensive resource for dissecting the developmental and stress-responsive roles of MADS-box genes in pepper. Full article

Juniperus przewalskii Komarov, an endemic conifer in the high-altitude mountains of the Qinghai–Tibet Plateau, develops its cones in a synergistic manner with the oligophagous pest Megastigmus sabinae Xu et He (Hymenoptera: Torymidae), forming a highly specialized interaction system. However, the physiological adaptation mechanisms underlying this interaction remain unclear. Feeding by M. sabinae larvae significantly induced defense responses in J. przewalskii cones. During the early instars (2nd~3rd) of M. sabinae larvae, infested J. przewalskii endosperms upregulated protein content (48.91%; 3rd instar), significantly enhanced peroxidase (POD) activity (71.10%; 2nd instar), and specifically enriched coumarins and cinnamaldehyde derivatives (2nd instar) to increase M. sabinae larvae metabolic costs. In later instars (4th~5th) of M. sabinae larvae, the infested endosperms downregulated starch content (29.69%; 4th instar), increased phenylalanine ammonia-lyase (PAL) activity (57.34%; 4th instar), and accumulated steroid derivatives to suppress larvae development. Conversely, M. sabinae larvae demonstrated unique adaptive strategies: maintaining high levels of glutathione S-transferase (GST) as an antioxidant defense system during early instars and upregulating the level of digestive enzymes in later stages to overcome host multi-layered defenses. Juniperus przewalskii counters pest infestation through dynamic nutrient modulation, temporal activation of protective enzymes, and a multi-layered chemical defense network. The adaptation of M. sabinae larvae appears to involve the developmental regulation of detoxification and digestive enzyme levels. This study provides novel insights that enrich coevolution theory in alpine ecosystems. Full article

The wet gluten content (WGC) of wheat is a key indicator of wheat-processing quality, and its genetic basis is extremely critical in breeding. This study evaluated the WGC of 207 wheat accessions under three growing seasons from a natural population. Nine quantitative trait loci (QTLs) explained 7.61–15.18% of phenotypic variation in a genome-wide association study (GWAS) using a 660K SNP array. Among them, qWGC6B.2 on chromosome 6BL was consistently detected across multiple environments, accounting for 10.08–12.27% of variation. Incorporating grain transcriptome data led to the identification of TaWGC6B.1 (TraesCS6B02G386700), which is highly expressed in developing endosperm and strongly correlated with WGC. A competitive allele specific PCR (KASP) marker development and validation indicated that the Whaas68366_GG allele significantly enhanced gene expression and WGC. This study identified key genes and molecular markers, providing theoretical and technical support for WGC genetic improvement in wheat (Triticum aestivum L.). Full article

Background/Objectives: FLOURY ENDOSPERM 2 (FLO2) is known to affect rice endosperm development and starch quality, yet its role in determining flour physicochemical behavior and endosperm structural integrity has not been quantitatively defined. This study aimed to elucidate how loss of FLO2 function alters starch organization and functional properties of rice flour. Methods: Two independent homozygous, T-DNA-free OsFLO2 knockout lines were generated in the japonica cultivar Dongjin using CRISPR/Cas9. Grain appearance was evaluated in mature seeds. Flour physicochemical properties were analyzed by Rapid Visco Analyzer (RVA) and differential scanning calorimetry (DSC). Amylopectin chain-length distribution was determined by isoamylase debranching followed by HPAEC-PAD, and endosperm microstructure was examined by scanning electron microscopy. Results: OsFLO2 mutants exhibited floury, opaque endosperms, with chalkiness increasing from 4.8% in the WT to 27–29%. RVA analysis showed a marked reduction in peak viscosity (1193 cP to 263–293 cP) and a decrease in pasting temperature (77.2 °C to 68.9–70.5 °C). DSC indicated a tendency toward reduced gelatinization enthalpy in the mutants. These changes were associated with a reduced proportion of short amylopectin chains (DP 6–12), decreased long chains (DP ≥ 37), and a relative increase in intermediate-long chains (DP 25–36), along with disrupted granule packing and a 1.33–1.36-fold increase in endosperm porosity. Conclusions: These results demonstrate that FLO2 plays an important role in maintaining the structural integrity of rice endosperm by harmonizing the microstructure of amylopectin with the thermal and gelatinization properties of starch. Full article

Water scarcity is a major constraint to upland rice production, and optimizing drought management to balance yield and quality is critical for sustainable agriculture. This study investigated the effects of three soil water potential (SWP) levels—0 kPa (control), −20 kPa (moderate drought), and −40 kPa (severe drought)—on grain quality, nitrogen metabolism, and endosperm structure in two upland rice varieties (Brazilian upland rice and Zhonghan 3). Compared with the control, moderate drought significantly improved grain quality: whole milled rice recovery increased by 5.3–7.8%, chalky grain rate decreased by 16.1–29.6%, amylose content declined by 8.65–12.19%, and glutelin content rose by 9.3–12.9%. Under moderate drought, nitrogen metabolism appeared to be upregulated, as indicated by increased activities of glutamine synthetase (GS, +18.6%) and glutamate dehydrogenase (GDH, +14.2%) and higher glutamate content (+21.4%) in Zhonghan 3, with similar but slightly attenuated responses in Brazilian upland rice. Moderate drought was associated with elevated glutelin accumulation and a more compact endosperm microstructure, suggesting a potential link between nitrogen metabolism and grain development. In contrast, severe drought impaired both grain quality and yield. Correlation analysis (n = 12) revealed that the GS/GDH ratio and glutelin content were significantly correlated with improved grain quality—positively with milled rice recovery (r = 0.58 * to 0.82 **, p < 0.05 or 0.01) and negatively with chalkiness, amylose content, and setback viscosity (r = −0.58 * to −0.93 **, p < 0.05 or 0.01). These findings indicate that maintaining SWP at −20 kPa represents a feasible strategy to enhance upland rice grain quality, offering a theoretical basis for water-saving, quality-oriented production systems. Full article

Galactomannans are a typical reserve polysaccharide in the endosperm of leguminous seeds; they turn the endosperm hard when dry and gelatinous and swollen when hydrated. Although galactomannans of several species have been biochemically characterized, little is known about their deposition within the endosperm. This study aimed to clarify how polysaccharides, galactomanans according to the literature, are produced and stored in the endosperm of Caesalpinia pulcherrima seeds by describing its structural and ultrastructural features throughout development. Samples of seeds at different developmental stages were collected and processed for study under light and electron microscopy. During development, the endosperm of C. pulcherrima undergoes substantial anatomical modifications associated with cellular cycles of polysaccharide release that gradually accumulates in the intercellular spaces. Endosperm cells exhibit an active Golgi apparatus with intense polysaccharide production, confirming their secretory function. In the mature endosperm, polysaccharides are stored in periplasmic and intercellular spaces rather than in thickened cell walls, as previously reported for other Leguminosae. By showing that galactomannans accumulate in periplasmic and intercellular spaces rather than in cell walls, our findings expand current understanding of endosperm diversity in Leguminosae and provide a foundation for future comparative studies on galactomannan synthesis and deposition across the family. Full article

Sweet corn is widely cultivated and valued for its palatability and nutritional quality, with kernels accumulating substantial carotenoids, which serve as essential antioxidants and vitamin A precursors. This study elucidated the genetic basis of carotenoid variation in sweet corn kernels by integrating quantitative trait loci (QTL) mapping with a candidate region association study. Seven carotenoid-related traits were quantified in a recombinant inbred line (RIL) population and its parental lines. QTL mapping based on a high-density genotyping-by-target sequencing (GBTS) map and BLUE values across two environments identified 15 loci on chromosomes 5, 6, 7, 8, and 9, explaining 3.83–17.25% of the phenotypic variance. Notably, chromosome 6 harbored a cluster of major-effect QTLs regulating β-cryptoxanthin, zeaxanthin, lutein, total carotenoids, and provitamin A contents. A regional association study within these linkage-defined intervals detected 71 significant SNPs (Bonferroni p < 1/n) and identified Zm00001d036238, encoding a GDSL esterase/lipase, as a strong candidate gene associated with β-cryptoxanthin accumulation. This gene exhibited kernel-specific expression in the endosperm and harbored a downstream cis-variant (Chr6: 78,466,427) correlated with increased carotenoid content. Allelic effect analysis indicated that the A/A genotype conferred markedly higher β-cryptoxanthin levels than other genotypes. Collectively, these findings provide valuable genetic resources for marker-assisted selection and biofortification breeding to enhance the nutritional quality of sweet corn. Full article

Grain filling governs grain weight formation in rice, while starch biosynthesis during this process critically determines both grain quality and yield. In this study, we characterized the heading date regulator OsPRR37 on regulating grain development, starch metabolism, and starch physicochemical properties. The osprr37 mutants exhibited undesirable agronomic traits, including reduced plant height, decreased grain thickness, lower 1000-grain weight, and diminished yield. Moreover, mutant endosperm displayed irregular starch packing, aberrant granules morphology, and decreased granule diameter. Impaired grain filling was observed in osprr37 mutants with reduced grain filling rates, which coincided with elevated soluble sugar content and reduced starch accumulation during grain development. Simultaneously, the expression of starch synthesis-related genes (SSRGs) was significantly altered. osprr37 mutants had decreased total starch and amylose content, leading to reduced starch crystallinity, lower structural order degree, and impaired gelatinization properties. Collectively, our results demonstrated that OsPRR37 functions as a key regulator of grain filling and starch biosynthesis, thereby determining starch composition and physicochemical properties that ultimately affect rice quality and yield. Full article

The H9N2 avian influenza virus (AIV) is difficult to prevent and control because of its low pathogenicity and frequent mutation. In a previous study, the HA (hemagglutinin) protein of H9N2 was expressed in a rice endosperm reactor and prepared into a subunit vaccine to immunize chickens and mice, both of which exhibited a good immunity effect. The results of the intermediate tests of the transgenic strains (AIV-1 and AIV-3) showed that the HA gene can be stably expressed. Agronomic traits, such as plant height and number of grains, were significantly optimized in the transgenic strains. Moreover, no exogenous HA genes were found in the leaves of the weeds, and it was initially determined that there was no risk of gene drift. This study provides key technical support for the commercialization of plant subunit vaccines for avian influenza viruses. Full article

Foxtail millet is a plant that is highly drought-resistant and rich in nutrients. Its grain structure traits are linked with water uptake during grain germination, which is closely related to plant density for high yield under rain fed regions; however, there is no related research. Using Micro-CT technology, we investigated a total of 15 internal structure traits of foxtail millet grains, such as the volume and surface area of the embryo, endosperm, cavity, hull, and whole grain, and mapped relevant quantitative trait loci (QTLs) using recombination inbred lines (RILs). With phenotypic variations in these traits and genome sequences of 100 foxtail millet RILs, four QTLs were identified. In combination with transcriptome profiling during grain development, we identified seven candidate genes that may play a role in the regulation of grain structure in foxtail millet. Full article

The LATERAL ORGAN BOUNDARIES DOMAIN (LBD) gene family encodes plant-specific transcription factors that play vital roles in plant growth, development, and stress responses. Rice (Oryza sativa L.), a staple food for more than half of the world’s population, also serves as an important model organism for monocot functional genomics. In this study, we conducted a comprehensive genomic survey of the OsLBD gene family in Oryza sativa ssp. japonica using the latest genomic sequence data. A total of 35 members of this family were identified through systematic characterization of their gene structures, conserved domains, phylogenetic relationships, and chromosomal distributions. Our analysis indicated that the expansion of OsLBD genes may have resulted mainly from segmental duplication, with these duplicated genes exhibiting diverse evolutionary fates ranging from functional conservation to expression divergence. Phylogenetic analysis further classified the OsLBD genes into two major groups: Class I and Class II. Expression profiling across various developmental stages demonstrated dynamic spatiotemporal regulation, with certain genes exhibiting tissue-specific expression, particularly in reproductive tissues. Furthermore, a comprehensive co-expression analysis of OsLBD genes and their co-regulators revealed multiple modules with tissue-specific roles in pollen cell wall synthesis and endosperm glycogen biosynthesis. Promoter analysis identified several cis-regulatory elements associated with hormone responses, stress adaptation, and developmental processes, consistent with the observed expression patterns under phytohormone treatments. Comparative genomics revealed a higher degree of synteny between rice and barley than between rice and Arabidopsis, highlighting the evolutionary conservation within the Poaceae family. This study provides a foundational framework for understanding the biological functions of OsLBD genes in rice and identifies promising candidate genes involved in vegetative and reproductive growth, development, and stress responses. Full article