Search Results (72)

Background and aims: Snap bean is a widely planted legume vegetable crop in the world, with tender pods as its edible organ. In the actual production process, excessive fiber content in bean pods can lead to a deterioration in their taste after cooking, seriously affecting their edible quality. In order to better study the mechanism of fiber formation in bean pod walls, we selected a bean pod fiber mutant (bfm) from the bean mutant library. Methods: Fiber content determination, cytological observation, and transcriptome and metabolome analysis were performed on the pod walls of mutant bfm and its wild-type at different developmental stages. Key results: The results showed that the crude fiber content of the bfm pod wall tissue was significantly higher than that of the wild type during the mature commercial pod stage, and cellulose may be the main factor causing the increase in fiber content in the bean pod wall. During the mature commercial pod stage, the number of cells in the pod wall tissue of bfm increased significantly compared to the wild type, with an increase in phloem fibers and thicker cell walls. It is speculated that this situation led to changes in fiber content in the mutant bfm. The combined analysis of transcriptome and metabolome showed that differentially expressed genes and metabolites were enriched in metabolic pathways and secondary metabolite biosynthesis pathways. Several metabolites, including glycine, L-glutamine, D-arabinitol, and D-ribose, were associated with the expression of Phvul.007G077800 (CTL) and Phvul.003G089600 (KOR). Conclusions: These genes and metabolites may participate in coordinated metabolic pathways that influence the availability of substrates and energy required for cellulose biosynthesis, thereby potentially contributing to cellulose accumulation in the pod wall. This study provides theoretical research on the mechanism of fiber synthesis in bean pod walls, and also to provide some reference for bean breeding improvement and application practice. Full article

Anoplophora glabripennis (ALB) is an invasive wood-boring cerambycid that causes extensive damage to hardwood host trees through sequential tissue penetration from the bark to the sapwood. Developmental biology of ALB is well established. However, interactions among its life cycle, environmental contaminants, and fungal associates remain poorly understood. In particular, the ecological relationships among microplastics, entomopathogenic fungi, and the fungal symbiont Fusarium solani (FSSC) within ALB-associated woody tissues remain largely uncharacterized. This review develops a conceptual anatomical framework integrating ALB developmental biology, fungal associations, frass deposition pathways, and potential microplastic interactions within woody host tissues. The framework was constructed through ecological literature synthesis and anatomical reconstruction. To our knowledge, this represents the first conceptual framework integrating ALB developmental anatomy, fungal symbiosis, and potential microplastic interactions within host tree gallery systems. A longitudinal cross-sectional model was developed to illustrate oviposition, larval gallery formation, pupation, and adult emergence in relation to the outer bark, cambium/phloem, sapwood, and heartwood. FSSC isolates previously documented on ALB egg surfaces following oviposition and within ALB frass were examined, thereby positioning the fungal symbiont both within and outside galleries produced by ALB throughout its life cycle. Previous studies have demonstrated that microplastics can be taken up by plant stem tissues and accumulate on the forest floor through atmospheric deposition. This widespread presence suggests that micro- and nanoplastics may penetrate sapwood and heartwood galleries through xylem and phloem flow. These transport pathways may overlap with regions where late-instar larvae actively forage. The integrative framework presented here highlights potential ecological interactions within the gallery microhabitat and provides a foundation for future experimental investigations into contaminant–pathogen–host dynamics in xylophagous insects. While we refrain from proposing specific management strategies, we present a conceptual framework to elucidate how microplastics may serve as incidental contact points for cerambycid anatomy and fungal propagules. We hypothesize that these interactions link microplastic pollution to invertebrate ecology. Microplastics may function as substrates for fungal spores within forest canopies and gallery systems, potentially influencing fungal persistence, contaminant transport, and ecological dynamics within infested forest habitats. Full article

Ruta graveolens L. fruits are densely covered with translucent dots corresponding to secretory cavities that accumulate bioactive metabolites, primarily essential oils. Immature fruits present an aromatic surface exudate, indicating the active release of secretory products despite the internal location of the cavities. This study investigated the origin, development, ultrastructure, and secretion-release mechanisms of fruit secretory cavities using light, scanning, and transmission electron microscopy. Secretory cavities originated from clusters of ground meristem cells associated with phloem strands. Lumen formation began with the collapse of central cells, while surrounding cells differentiated into a metabolically active secretory epithelium rich in polymorphic plastids, smooth endoplasmic reticulum, mitochondria, vesicles, and lipid bodies. Mature cavities consisted of a multilayered epithelium surrounding a large lumen and enclosed by a parenchymatous sheath. Progressive lysis of inner epithelial cells contributed to lumen expansion and secretion accumulation. As cavities enlarged, they became positioned immediately beneath the epidermis, whose cells became compressed and flattened. Secretion was released through the rupture of glandular and epidermal cells and through stomata located in epicarp depressions. Ultrastructural evidence indicates the combined operation of eccrine, granulocrine, and holocrine secretion mechanisms. Pectin–cellulosic wall thickenings likely function as apoplastic barriers, directing secretion toward the lumen and protecting adjacent tissues. Full article

The red turpentine beetle, Dendroctonus valens LeConte, is an important phloem-feeding pest of pine forests in China. RNA interference (RNAi) is a conserved, sequence-specific gene-silencing mechanism induced by double-stranded RNA (dsRNA), and has become an important molecular tool for screening and evaluating potential targets for pest management owing to its high efficiency, target specificity, and relative environmental safety. In this study, six candidate genes were selected, including mesh and ssk responsible for gut barrier formation, actin involved in cellular structure maintenance, iap involved in apoptosis regulation, hsp70-2 responsible for stress response, and v-atpaseE involved in ion transport and cellular homeostasis. The effects of dsRNA microinjection on gene silencing and mortality were then evaluated in both larvae and adults of D. valens. Following dsRNA treatment, all six candidate genes were significantly downregulated in both larvae and adults, with v-atpaseE showing the strongest transcript suppression in larvae. Survival analysis revealed target-dependent lethal effects: v-atpaseE caused rapid larval mortality, reaching 100% by day 3, whereas ssk caused the strongest adult mortality, reaching 100% by day 5, and mesh also induced substantial adult mortality. In contrast, actin, iap, and hsp70-2 produced weaker or slower lethal effects. These results indicate that dsRNA injection can induce effective gene silencing in D. valens and that the resulting phenotypic responses differ among target genes and between life stages. Taken together, v-atpaseE and ssk represent the most promising candidate targets for further development of RNAi-based management strategies against D. valens. Full article

Low-temperature stress during the jointing stage severely disrupts the coordination of the source–flow–sink system in winter wheat. To elucidate the underlying mechanism, three wheat cultivars with different winter habits (Zhenmai 12, Jimai 22, and Shannong 38) were selected and subjected to six temperature levels (−6 °C to 8 °C) and three stress durations (2–6 days). The effects of vascular bundle traits on the transport of photosynthetic products, dry matter distribution, and yield formation were analyzed. The results showed that Zhenmai 12 and Jimai 22 completely ceased photosynthesis under 0 °C and −3 °C, respectively. The leaf vascular bundle area continuously decreased with increasing low-temperature stress, while the proportion of xylem and phloem initially increased by approximately 15% and 10%, respectively, before rapidly decreasing to 65% of the control value. In the stem, the three vascular bundle parameters initially increased by 20%, 25%, and 20%, respectively, before quickly decreasing to 50%. Changes in the vascular bundle structure weakened the transport capacity of assimilates, with dry matter in leaves and stems decreasing by 15–20% and 10%, respectively, while the root dry matter increased by 20–30%. Correlation analysis revealed highly significant relationships (p < 0.001) between vascular bundle parameters and yield components. Principal component and cluster analyses indicate that the area of leaf and stem vascular bundles, maximum net photosynthetic rate, and water use efficiency may be key indicators in explaining the variation in yield. Radar plots further validated this finding, showing that Zhenmai 12 and Jimai 22 are more sensitive to changes in the maximum net photosynthetic rate, while Shannong 38 exhibits a greater sensitivity to changes in water use efficiency. Based on existing research on photosynthetic pathways and dry matter distribution, this study innovatively investigates the potential relationship between material transport and yield formation under low-temperature stress during the jointing stage from the perspective of anatomical structure and functional coupling. The findings provide new insights into understanding the structural impact of low-temperature stress on crop yield formation and offer theoretical support for identifying the structural basis of limited material transport under stress and for developing disaster diagnostic models driven by structural parameters. Full article

Enhancing rice yield under high-input systems increasingly relies on optimizing physiological processes rather than further increasing external inputs. This study aimed to clarify the physiological basis underlying the yield advantage of super hybrid rice, focusing on photosynthetic capacity and assimilate transport. We compared super hybrid rice (Yliangyou 3218 and Yliangyou 5867) with super conventional rice (Zhendao 11 and Nanjing 9108) under field conditions in 2023–2024. Super hybrid rice consistently outperformed super conventional rice, with grain yield 19.7% higher in 2023 and 23.7% higher in 2024, primarily due to an increased number of spikelets per panicle, and grain yield was also positively correlated with photosynthetic capacity (net photosynthetic rate, stomatal conductance, maximum carboxylation rate, maximum electron transport rate and triose phosphate utilization rate). In 2024, spikelets per panicle and grain yield were also positively associated with phloem soluble sugar and vascular bundle number, indicating that enhanced assimilate transport contributed to higher spikelet formation. These results demonstrate that, compared to super conventional rice, the yield advantage of super hybrid rice is underpinned by coordinated enhancement of photosynthesis and assimilate transport, highlighting the importance of source–sink optimization for further yield improvement. Full article

The vascular cambium serves as the fundamental meristem for wood formation. It determines wood biomass and structural properties by balancing self-renewal with the bidirectional production of xylem and phloem. This process is controlled by a complex network of peptides, transcription factors, and phytohormones. These regulatory networks coordinate cambial stem cell activity, balancing cell division and differentiation. Additionally, layers of regulation such as chromatin state, protein stability, and non-coding RNAs add significant complexity to these networks. Emerging single-cell and spatial transcriptomics, together with quantitative modeling, now resolve cambial heterogeneity, predicting the dynamic characteristics of wood formation. This review synthesizes current knowledge of cambial regulation, highlighting how feedback loops, spatial gradients, and dynamic signaling networks collectively orchestrate the predictive potential for improving cambial activity and wood formation. Full article

Agarwood is highly valued; however, its formation process is relatively slow. In this study, carbon isotope labeling was used to investigate the effects of girdling on agarwood formation. The starch, soluble sugar, and essential oil contents of the stems above the girdle were higher than those of the stems below the girdle and those of stems without girdling. Carbon isotope labeling revealed that girdling obstructed the transport of non-structural carbohydrates synthesized by the leaves to the stem below the girdle. The concentration of ¹³C in starch, soluble sugars, and essential oils in stems above the girdle was significantly higher than that in stems below the girdle and in stems without girdling. Phenotypic observations revealed that the area of agarwood formation was more extensive in regions closer to the phloem. Slice staining and variations in starch and soluble sugar content showed that starch was converted into soluble sugars during agarwood formation. This study demonstrates that newly synthesized non-structural carbohydrates from leaves following agarwood-inducing treatment contribute as raw materials for agarwood formation. Girdling increases the levels of non-structural carbohydrates in the stem above the girdle, thereby enhancing agarwood formation. Full article

Soybean (Glycine max) is a globally important crop valued for its high seed oil and protein content. However, lodging remains a major abiotic constraint that causes substantial yield losses. Lodging resistance is primarily determined by stem strength and toughness, which are governed by stem anatomical organization, vascular tissue development, and the composition and architecture of secondary cell walls (SCWs). This review synthesizes current knowledge on anatomical, structural, and genetic factors that are implicated in stem mechanical performance in dicotyledonous plants, with particular emphasis on vascular cambium activity, xylem and phloem differentiation, and the biosynthesis of major SCW components, including cellulose, hemicellulose, and lignin. These processes collectively determine stem rigidity, flexibility, and resistance to mechanical stress. By integrating insights from model species, especially Arabidopsis thaliana, and non-soybean dicots, this review highlights conserved regulatory pathways controlling stem development and SCW formation that are directly relevant to soybean improvement. The synthesis provides a translational framework for understanding how conserved anatomical and genetic mechanisms can be leveraged to enhance soybean stem strength, toughness, and lodging resistance. Overall, this review provides a conceptual foundation for future functional studies and breeding strategies to improve soybean yield stability and adaptability across diverse agronomic conditions. Full article

Electron transfer (ET) is a foundational biogeochemical process in paddy soils, distinctively molded by alternating anaerobic-aerobic conditions from flooding-drainage cycles. Despite extensive research on heavy metal(loid) (denoted as “HM”, e.g., As, Cd, Cr, Hg) dynamics in paddies, ET has not been systematically synthesized as a unifying regulatory mechanism, and the trade-offs of ET-based mitigation strategies remain unclear. These critical gaps have drastically controlled HMs’ mobility, which further modulates bioavailability and subsequent accumulation in rice (Oryza sativa L., a staple sustaining half the global population), posing substantial food safety risks. Alongside progress in electroactive microorganism (EAM) research, extracellular electron transfer (EET) mechanism delineation, and soil electrochemical monitoring, ET’s role in orchestrating paddy soil HM dynamics has garnered unparalleled attention. This review explicitly focuses on the linkage between ET processes and HM biogeochemistry in paddy ecosystems: (1) elucidates core ET mechanisms in paddy soils (microbial EET, Fe/Mn/S redox cycling, organic matter-mediated electron shuttling, rice root-associated electron exchange) and their acclimation to flooded conditions; (2) systematically unravels how ET drives HM valence transformation (e.g., As(V) to As(III), Cr(VI) to Cr(III)), speciation shifts (e.g., exchangeable Cd to oxide-bound Cd), and mobility changes; (3) expounds on ET-regulated HM bioavailability by modulating soil retention capacity and iron plaque formation; (4) synopsizes ET-modulated HM accumulation pathways in rice (root uptake, xylem/phloem translocation, grain sequestration); (5) evaluates key factors (water management, fertilization, straw return) impacting ET efficiency and associated HM risks. Ultimately, we put forward future avenues for ET-based mitigation strategies to uphold rice safety and paddy soil sustainability. Full article

Boron (B) is a crucial micronutrient for the initial formation, development, and final quality of fruits, as it affects their physical and chemical properties and helps prevent various functional disorders. Recently, numerous physiological disorders in fruits have been reported, which have been linked to B deficiency. However, there is still uncertainty about whether these issues are directly related to B, other nutrients, their combinations, or environmental conditions. This review aims to compile current and accurate information on how B is absorbed by plants, its role in the cell wall and membrane, its impact on flowering and fruit set, and its influence on physical and chemical properties, as well as its role in preventing physiological disorders. This review examines the latest studies on B published in major scientific journals (Elsevier, Springer, MDPI, Frontiers, Hindawi, Wiley, and SciELO). Boron is mobile in the xylem and slightly mobile in the phloem, and it plays a crucial role in pollination and fruit set. It reduces mass loss, maintains firmness, improves color, and results in larger, heavier fruits. Also, boron increases soluble solids, regulates total titratable acidity and pH, decreases respiration rate, and stabilizes ascorbic acid by delaying its breakdown. It also helps prevent disorders such as splitting, cork spots, internal rot, shot berry in grapes, blossom end rot, and segment drying in citrus. Foliar or soil application of B enhances fruit yield and post-harvest quality. Full article

Meloidogyne incognita (M. incognita) is a devastating root-knot nematode that parasitizes a broad range of crop species by inducing the formation of giant cells (GCs) in host roots, thereby facilitating nutrient acquisition. This process profoundly alters host sugar metabolism, yet the molecular regulators underlying sugar dynamics during infection remain poorly understood in cucumber. In this study, we investigated the role of the cucumber alkaline α-galactosidase gene (CsAGA1) in M. incognita-infected roots. Histochemical analysis of proCsAGA1::GUS transgenic lines demonstrated that CsAGA1 is spatially localized to nematode-induced feeding sites, with its expression markedly induced in GCs and phloem-adjacent tissues during infection. Functional analyses revealed that silencing CsAGA1 impaired root and gall development. CsAGA1-silenced plants exhibited increased gall numbers (per gram root) but significantly reduced root growth and smaller galls compared to controls. These results indicate that CsAGA1 is required for proper gall expansion and root growth during M. incognita infection. This study provides novel insight into the sugar-mediated regulation of host–nematode interactions, and CsAGA1 emerges as a potential target for the biological control of M. incognita. Full article

Ginseng rusty root symptoms (GRSs) compromise the yield and quality of Panax ginseng. While transcriptomic analyses have demonstrated extensive remodeling of stress signaling networks, the post-transcriptional defense circuitry remains obscure. We profiled alternative splicing (AS) in three phloem tissues, the healthy phloem (AG), the non-reddened phloem neighboring lesions (BG), and the reddened lesion core (CG), to delineate AS reprogramming during GRS progression. The frequency of AS was sharply elevated in CG, with intron retention predominating. Extensive gains and losses of splice events indicate large-scale rewiring of the splice network. Overlapping differentially alternative spliced genes (DAGs) identified in both CG vs AG and CG vs BG contrasts were significantly enriched for RNA–spliceosome assembly and stress–response pathways, revealing a conserved post-transcriptional response associated with lesion formation. Integrative analysis of differentially expressed genes uncovered 671 loci under dual regulation; functional classification categorized these genes in receptor-like kinase signaling and chromatin-remodeling modules, underscoring the synergy between AS and transcriptional control. Moreover, the B subgenome disproportionately contributed stress-responsive transcripts in diseased tissue, suggesting an adaptive, subgenome-biased strategy. These findings demonstrate that dynamic AS remodeling and subgenome expression bias jointly orchestrate ginseng defense against GRS and provide a framework for breeding disease-resilient crops. Full article

Resin canals serve as a natural feature with the function of a defense system against fungi, bacteria, and insects. Trees can form these canals in response to mechanical injury and ecological disturbance. Factors, such as plant hormones and temperature, influence cambial activity and cell differentiation. This study examined the effects of increased temperature and plant hormones on cambial reactivation, vessel formation, and resin canal formation using localized heating and the application of the ethylene generator ethephon to dormant stems of the Toxicodendron vernicifluum seedlings. Localized heating was achieved by wrapping an electric heating ribbon around dormant stems, while ethephon was applied to the bark surface. Treatment was initiated on 29 January 2021, including control, heating, ethephon, and a combination of heating and ethephon. Cambial reactivation and resin canal formation were monitored using light microscopy, and bud growth was recorded with a digital camera. Localized heating induced earlier phloem reactivation, cambial reactivation, and xylem differentiation, increasing the number of vessels. The application of exogenous ethylene delayed these processes. The combination of localized heating and exogenous ethylene application resulted in smaller vessels and larger resin canals. These results suggest that increased temperature plays a significant role in cambial reactivation and vessel formation in ring-porous hardwood and that ethylene affects vessel differentiation and resin canal development. Full article

Pilostyles, an endoparasitic genus within the Apodanthaceae family, grows inside host stems with flowers and fruits being the only external manifestations. Previous studies of P. berteroi growing on Adesmia trijuga provided limited details of the endophyte and omitted the origin of flowers and sinker structure. This study, using classical methods of optical microscopy applied to the analysis with scanning electron microscopy and confocal laser scanning microscopy, expands the understanding of the P. berteroi/A. trijuga complex. We find that P. berteroi develops isophasically with its host, forming endophytic patches between the host’s secondary phloem cells. The parasitized Adesmia stem’s cambium primarily produces xylem parenchyma, with limited vessel production and halting fiber formation. The radial polarization of endophytic patches led to the formation of floral meristems. Flowers develop endogenously and emerge by the breakthrough of the host stem. Flowers are connected to the host cambium via chimeric sinkers, combining P. berteroi parenchyma and tracheoids with Adesmia vessels. Unlike previous studies that show uniformity among Pilostyles species, our analysis reveals new insights into the structural interaction between P. berteroi and A. trijuga. Full article