Cell Wall Thickness Research Articles

Arabinosylation of cell wall extensin is required for the directional response to salinity in roots.

Soil salinity is a major contributor to crop yield losses. To improve our understanding of root responses to salinity, we developed and exploited a real-time salt-induced tilting assay. This assay follows root growth upon both gravitropic and salt challenges, revealing that root bending upon tilting is modulated by Na+ ions, but not by osmotic stress. Next, we measured this salt-specific response in 345 natural Arabidopsis (Arabidopsis thaliana) accessions and discovered a genetic locus, encoding the cell wall-modifying enzyme EXTENSIN ARABINOSE DEFICIENT TRANSFERASE (ExAD) that is associated with root bending in the presence of NaCl (hereafter salt). Extensins are a class of structural cell wall glycoproteins known as hydroxyproline (Hyp)-rich glycoproteins, which are posttranslationally modified by O-glycosylation, mostly involving Hyp-arabinosylation. We show that salt-induced ExAD-dependent Hyp-arabinosylation influences root bending responses and cell wall thickness. Roots of exad1 mutant seedlings, which lack Hyp-arabinosylation of extensin, displayed increased thickness of root epidermal cell walls and greater cell wall porosity. They also showed altered gravitropic root bending in salt conditions and a reduced salt-avoidance response. Our results suggest that extensin modification via Hyp-arabinosylation is a unique salt-specific cellular process required for the directional response of roots exposed to salinity.

The roles of cell wall polysaccharides in response to waterlogging stress in Brassica napus L. root

BackgroundBrassica napus L. (B. napus) is susceptible to waterlogging stress during different cultivation periods. Therefore, it is crucial to enhance the resistance to waterlogging stress to achieve a high and stable yield of B. napus.ResultsHere we observed significant differences in the responses of two B. napus varieties in root under waterlogging stress. The sensitive variety (23651) exhibited a more pronounced and rapid reduction in cell wall thickness and root integrity compared with the tolerant variety (Santana) under waterlogging stress. By module clustering analysis based on transcriptome data, we identified that cell wall polysaccharide metabolism responded to waterlogging stress in root. It was found that pectin content was significantly reduced in the sensitive variety compared with the tolerant variety. Furthermore, transcriptome analysis revealed that the expression of two homologous genes encoding polygalacturonase-inhibiting protein 2 (PGIP2), involved in polysaccharide metabolic pathways, was highly upregulated in root of the tolerant variety under waterlogging stress. BnaPGIP2s probably confer waterlogging resistance by inhibiting the activity of polygalacturonases (PGs), which in turn reduces the degradation of the pectin backbone polygalacturonic acid.ConclusionsOur findings demonstrate that cell wall polysaccharides in root plays a vital role in response to the waterlogging stress and provide a theoretical foundation for breeding waterlogging resistance in B. napus varieties.

Analysis of R2R3-MYB Repressor Subfamily Identifies FcMYB57 as a Negative Regulator of Anthocyanin Biosynthesis in Ficus carica L. Fruit

Dry fig is a traditional healthy snack and has important economic value in a number of Mediterranean and Middle Eastern countries. Cultivars with no anthocyanin accumulation in the fruit peel are preferred for dry fig production. R2R3-MYB transcription factors have promotive or repressive regulatory roles in plant anthocyanin biosynthesis. In this study, 113 R2R3-MYB genes were identified in Ficus carica, 3 of which were assigned to the S4 subfamily of flavonoid-biosynthesis repressors. FcMYB57 was further recruited as a candidate anthocyanin-biosynthesis repressor based on its sequence features and expression, which was significantly negatively correlated with that of anthocyanin-biosynthesis structural genes. Transient overexpression of FcMYB57 in strawberry totally inhibited fruit pigmentation and significantly increased fruit firmness. The metabolomic analysis confirmed a significant reduction in the contents of cyanidin-3-O-glucoside and pelargonidin-3-O-glucoside, as well as other flavonoids, and transmission electron microscopy revealed an increment in cell-wall thickness. Transcriptome analysis showed downregulation of anthocyanin-biosynthesis structural genes and upregulation of genes related to xylan synthesis. Yeast one-hybrid and dual luciferase assays demonstrated a negative regulatory effect of FcMYB57 on the promoter of FcUFGT3 (UDP glucose-flavonoid 3-O-glcosyl-transferase). Yeast two-hybrid assay showed that FcMYB57 does not interact with FcbHLH42, 3, 14, MYC2, or FcTTG1, all of which have a previously identified or predicted role in flavonoid biosynthesis, however, interaction was detected with FcTPL (Topless), suggesting that FcMYB57 serves as an active repressor of anthocyanin biosynthesis. This is the first identification of an anthocyanin-biosynthesis repressor in fig, with a possible role in fig fruit quality.

Regulatory networks of senescence-associated gene-transcription factors promote degradation in Moso bamboo shoots.

Bamboo cultivation, particularly Moso bamboo (Phyllostachys edulis), holds significant economic importance in various regions worldwide. Bamboo shoot degradation (BSD) severely affects productivity and economic viability. However, despite its agricultural consequences, the molecular mechanisms underlying BSD remain unclear. Consequently, we explored the dynamic changes of BSD through anatomy, physiology and the transcriptome. Our findings reveal ruptured protoxylem cells, reduced cell wall thickness and the accumulation of sucrose and reactive oxygen species (ROS) during BSD. Transcriptomic analysis underscored the importance of genes related to plant hormone signal transduction, sugar metabolism and ROS homoeostasis in this process. Furthermore, BSD appears to be driven by the coexpression regulatory network of senescence-associated gene transcription factors (SAG-TFs), specifically PeSAG39, PeWRKY22 and PeWRKY75, primarily located in the protoxylem of vascular bundles. Yeast one-hybrid and dual-luciferase assays demonstrated that PeWRKY22 and PeWRKY75 activate PeSAG39 expression by binding to its promoter. This study advanced our understanding of the molecular regulatory mechanisms governing BSD, offering a valuable reference for enhancing Moso bamboo forest productivity.

LC-MS/MS phenolic profileand remedial role ofUrtica dioica extract against Li2CO3-induced toxicity.

In this study, the protective role of Urtica dioica extract (Udex) against Li2CO3 toxicity in Allium cepa L. was investigated using various parameters such as germination rates, root growth, weight gain, mitotic index (MI), malondialdehyde (MDA), micronucleus (MN), antioxidant enzyme activity, chromosomal abnormalities (CAs) and anatomical changes. As the biological activity of Udex is related to its active content, the profile of phenolic compounds was determined by LC-MS/MS analysis. Li2CO3 caused abnormalities in the tested parameters and serious regressions in germination parameters. Application of 100mg/L Li2CO3 reduced the chlorophyll a and b contents by 73.04% and 65.7%, respectively. Li2CO3 application exhibited a cytotoxic effect by inducing significant decreases in MI and increases in the frequency of MN, and also showed a genotoxic effect by causing CAs. After 100mg/L Li2CO3 treatment, MDA, proline, superoxide dismutase, and catalase levels increased by 54.9%, 58.5%, 47.8%, and 52.3%, respectively. Li2CO3 and Udex co-administration resulted in a regression in increased biochemical parameters and genotoxicity parameters, and an improvement in germination parameters. Furthermore, Udex demonstrated efficacy in mitigating the detrimental effects of Li2CO3 on the root tip, particularly in the 200µg/mL Udex-treated group. The thickening of the cortex cell wall and conduction tissue, which is commonly induced by Li₂CO₃, was not observed in the Udex-treated group. The protective effect of Udex can be explained by the phenolic compounds it contains. Rutin was detected as the major component in Udex and other phenolics were listed according to their presence rate as protecatechuic acid > caffeic acid > p-coumaric acid > syringic acid > rosemarinic acid > epicatechin. Li ions, which increase in the environment after industrialization, are an important environmental pollutant and exhibit toxicity that affects many pathways in organisms. Scientific research should not only detect these toxic effects but also develop solutions to such problems. In this study, it was determined that the Udex application had a toxicity-reducing role against Li2CO3 toxicity. Also, it has been demonstrated that A. cepa is an important indicator in determining this toxicity and toxicity-reducing applications.

Investigation of the protective role of Ginkgo biloba L. against phytotoxicity, genotoxicity and oxidative damage induced by Trifloxystrobin

Trifloxystrobin (TFS) is a widely used strobilurin class fungicide. Ginkgo biloba L. has gained popularity due to its recognized medicinal and antioxidant properties. The aim of this study was to determine whether Ginkgo biloba L. extract (Gbex) has a protective role against TFS-induced phytotoxicity, genotoxicity and oxidative damage in A. cepa. Different groups were formed from Allium cepa L. bulbs subjected to tap water (control), 200 mg/L Gbex (Gbex1), 400 mg/L Gbex (Gbex2), 0.8 g/L TFS solution (TFS), 200 mg/L Gbex + 0.8 g/L TFS (TFS + Gbex1) and 400 mg/L Gbex + 0.8 g/L TFS (TFS + Gbex2), respectively. The phenolic composition of Gbex and alterations in the morphological, physiological, biochemical, genotoxicity and anatomical parameters were evaluated. Rutin, protocatechuic acid, catechin, gallic acid, taxifolin, p-coumaric acid, caffeic acid, epicatechin, syringic acid and quercetin were the most prevalent phenolic substances in Gbex. Rooting percentage, root elongation, weight gain, chlorophyll a and chlorophyll b decreased by approximately 50%, 85%, 77%, 55% and 70%, respectively, as a result of TFS treatment compared to the control. In the TFS group, the mitotic index fell by 28% compared to the control group, but chromosomal abnormalities, micronuclei frequency and tail DNA percentage increased. Fragment, vagrant chromosome, sticky chromosome, uneven chromatin distribution, bridge, vacuole-containing nucleus, reverse polarization and irregular mitosis were the chromosomal abnormalities observed in the TFS group. The levels of proline (2.17-fold) and malondialdehyde (2.71-fold), as well as the activities of catalase (2.75-fold) and superoxide dismutase (2.03-fold) were increased by TFS in comparison to the control. TFS-provoked meristematic disorders were damaged epidermis and cortex cells, flattened cell nucleus and thickened cortex cell wall. Gbex combined with TFS relieved all these TFS-induced stress signs in a dose-dependent manner. This investigation showed that Gbex can play protective role in A. cepa against the phytotoxicity, genotoxicity and oxidative damage caused by TFS. The results demonstrated that Gbex had this antioxidant and antigenotoxic potential owing to its high phenolic content.

Mechanical properties of a novel negative Poisson's ratio gradient structure

A novel cellular structure is proposed based on bionic structure with negative Poisson's ratio characteristic, and the cell is periodically expanded in the in-plane direction to create a new honeycomb structure. The influence of gradient changes of the structural parameters on the load-bearing capacity and damping characteristics of the structure is investigated through a combination method of finite element numerical simulations and experiments. The results indicate that the concentric gradient arrangement of cell wall thickness and angle parameters, and the symmetrical gradient arrangement of cell height, wall thickness and angle parameters have the most significant influence on the static bearing capacity of the structure. In contrast, the gradient arrangement under the corner circle diameter has minimal effect on the static bearing capacity of the structure. Under the same conditions, the peak values of the transmissibility of C2 (large angle at constraint end and loading end, and smaller angle in the middle) and C3 structures (angle gradually increases from the loading end to the constraint end) are significantly reduced between the frequency 2 Hz and 1024 Hz. The peak values of the transmissibility of the structures C2 and C3 are respectively decreased by 20% and 25% compared to that of the non-gradient structure. This shows that the vibration damping effect of these two structures is better. The structure with the gradient change and the structure without the gradient change of the new honeycomb structure can both achieve certain vibration reduction and isolation from the middle to high frequency range.

Staphylococcus aureus Stress Response to Bicarbonate Depletion.

Bicarbonate and CO2 are essential substrates for carboxylation reactions in bacterial central metabolism. In Staphylococcus aureus, the bicarbonate transporter, MpsABC (membrane potential-generating system) is the only carbon concentrating system. An mpsABC deletion mutant can hardly grow in ambient air. In this study, we investigated the changes that occur in S. aureus when it suffers from CO2/bicarbonate deficiency. Electron microscopy revealed that ΔmpsABC has a twofold thicker cell wall thickness compared to the parent strain. The mutant was also substantially inert to cell lysis induced by lysostaphin and the non-ionic surfactant Triton X-100. Mass spectrometry analysis of muropeptides revealed the incorporation of alanine into the pentaglycine interpeptide bridge, which explains the mutant's lysostaphin resistance. Flow cytometry analysis of wall teichoic acid (WTA) glycosylation patterns revealed a significantly lower α-glycosylated and higher ß-glycosylated WTA, explaining the mutant's increased resistance towards Triton X-100. Comparative transcriptome analysis showed altered gene expression profiles. Autolysin-encoding genes such as sceD, a lytic transglycosylase encoding gene, were upregulated, like in vancomycin-intermediate S. aureus mutants (VISA). Genes related to cell wall-anchored proteins, secreted proteins, transporters, and toxins were downregulated. Overall, we demonstrate that bicarbonate deficiency is a stress response that causes changes in cell wall composition and global gene expression resulting in increased resilience to cell wall lytic enzymes and detergents.

Effects of foliar treatments with urea and nano-urea on the cell walls of Monastrell grape skins

Cell wall composition can be affected by nitrogen availability in the vineyard. Foliar application of urea is effective in supplying nitrogen needs and increasing the nitrogen content of musts. Due to the low recoveries of urea fertilisation, more effective application methods such as the use of nanotechnology are needed. In this work, the effect on the composition of Monastrell grape skin cell walls, after foliar application of urea and amorphous calcium phosphate nano-particles doped with urea was studied. The treatments with urea and nano-urea, although the urea content in the nano-treatment was eight times lower than in the conventional treatment, produce an equivalent modification of the cell wall. In fact, both treatments produced an increase in cell wall thickness and in cell wall composition, contents of proteins, hemicellulose and uronic acids also increased. However, phenolic compounds were not affected and cellulose showed lower concentrations than control grapes. Regarding the spectrophotometric parameters of the wine studied, the anthocyanins content and colour intensity were reduced in wines with both treatments and the total polyphenol index was slightly affected.

Nonlinear models based on leaf architecture traits explain the variability of mesophyll conductance across plant species.

Mesophyll conductance ( ) describes the efficiency with which moves from substomatal cavities to chloroplasts. Despite the stipulated importance of leaf architecture in affecting , there remains a considerable ambiguity about how and whether leaf anatomy influences . Here, we employed nonlinear machine-learning models to assess the relationship between 10 leaf architecture traits and . These models used leaf architecture traits as predictors and achieved excellent predictability of . Dissection of the importance of leaf architecture traits in the models indicated that cell wall thickness and chloroplast area exposed to internal airspace have a large impact on interspecific variation in . Additionally, other leaf architecture traits, such asleaf thickness, leaf densityand chloroplast thickness, emerged as important predictors of . We also found significant differences in the predictability between models trained on different plant functional types. Therefore, by moving beyond simple linear and exponential models, our analyses demonstrated that a larger suite of leaf architecture traits drive differences in than has been previously acknowledged. These findings pave the way for modulating by strategies that modify its leaf architecture determinants.

Biochar and soil contributions to crop lodging and yield performance - A meta-analysis

Applying biochar has beneficial effects on regulating plant growth by providing water and nutrient availability for plants due to its physicochemical characteristics. Nevertheless, it is still unclear how soil and biochar interactions strengthen crop lodging resistance. The objective of the current study was to find out how soil physicochemical conditions and alterations in biochar affect lodging resistance and crop productivity in cereals. To do this, a meta-analysis was carried out using nine groups of effective variables including type of feedstock, pyrolysis temperature, application rate, soil pH, total nitrogen, available phosphorus, potassium, organic matter (OM), and soil texture. Results showed that straw-derived biochar caused the highest positive effect size in the dry weight of biomass (20.5%) and grain yield (19.9%). Also, the lowest lodging index was observed from straw (−8.3%) and wood-based (−5.6%) biochars. Besides, the high application rate of biochar results in the highest positive effect sizes of plant cellulose (8.1%) and lignin content (7.6%). Soils that contain >20 g kg−1 OM, resulted in the highest positive effect size in dry biomass (27.9%), grain yield (30.2%), and plant height (4.7%). Also, fine-textured soil plays an important role in increasing polymers in the anatomical structure of plants. Overall, the strong connection between biochar and soil processes, particularly the availability of OM, could strengthen plants' ability to tolerate lodging stress and contribute to high nutrient efficiency in terms of crop output and cell wall thickening.

The structural organization of the outer tissues in the gametophytic stem of the umbrella moss Hypnodendron menziesii optimizes load bearing.

The ultrastructural design and biochemical organization of the significantly thickened outer tissues of the gametophytic stem of Hypnodendron menziesii optimizes load bearing of the stem. Hypnodendron menziesii is a bryoid umbrella moss growing in high humid conditions on the forest floors of New Zealand. The erect gametophyte bears up to eight whorls of branches in succession, spreading across the stem that bears the heavy weight of branches with highly hydrated leaves. Our investigation using a combination of light microscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and TEM-immunolabeling techniques provided novel information on the structural design and biochemical organization of greatly thickened cell walls of epidermal, hypodermal, and outermost cortical tissues, comparing underlying thin-walled cortical tissues in the gametophytic stem. Probing into the ultrastructure of the cell wall architecture of these target tissues by TEM and SEM revealed the cell walls to display a multilamellar organization, in addition to demonstrating the presence of an electron-dense substance in the cell wall, presumably flavonoids. The pattern of distribution and concentration of rhamnogalacturonan, homogalacturonan, and heteromannan, as determined by immunogold labeling, suggests that it is the combination of structural and molecular design of the cell wall that may optimize the mechanical function of the epidermal, hypodermal, and outer cortical tissues. Statistical relationships between the overall thickness of epidermal, hypodermal, and outer cortical cell walls, the lumen area of cells and the percentage area of cell wall occupied in these tissues at different heights of the stem, and thickness of secondary cell wall layers (L1-L4/5) were explored. The results of these analyses unequivocally support the contribution of outer tissues to the mechanical strength of the resilient stem.

Assessing the effects of mechanical damage on optical properties of strawberries in the 950−1650 nm range

To investigate the effect mechanism of early damage on optical properties of strawberries, the optical parameters, internal qualities and microstructure parameters of bruised samples and intact ones were acquired and quantitatively analyzed. The results showed that the soluble solids content increased with damage time, while the moisture content decreased. Firmness showed no difference between intact and bruised samples. The cell circularity (Cc) initially decreased, then slightly increased over damage time. The average cell diameter (Davg) increased with longer damage durations, and the average values of cell wall thickness (Tcw) decreased with longer damage durations. The absorption coefficient (µα) values of bruised samples were higher than the intact ones at 970 nm and 1190 nm. For reduced scattering coefficient (µ′s), at 970 nm and 1190 nm, differences were observed between intact strawberries and bruised samples subjected to three different durations of damage. The average R values of µ′s with Cc, Tcw and Davg were 0.79, 0.93 and −0.93, respectively, confirming a strong correlation of µ′s with cell diameter and cell wall thickness. The support vector machine classification model built based on µα spectra had better performance than that based on µ′s spectra, and the model based on combinations of µα and µ′s (µeff) exhibited the highest accuracy for both the calibration set and prediction set with accuracies of 96.00 % and 92.19 %, respectively. The study provides a theoretical basis for detecting latent damaged strawberries based on optical properties.

A gyroid TPMS heat sink for electronic cooling

The trend toward thinner and lighter electronic devices necessitates developing advanced thermal management solutions to address modern microprocessors’ escalating heat dissipation demands. This study introduces an advanced thermal solution incorporating a gyroid TPMS structure with remarkable physical properties for microprocessor cooling. Detailed investigations were conducted using a full-scale heat sink model to understand the inner geometric structure, flow, and heat transfer characteristics within a gyroid heat sink (GHS). The thermo-hydraulic performance of the GHS design was systematically assessed against that of a pinfin heat sink (PHS) across different porosities and flow rates. Both heat sinks were evaluated under non-uniform heating conditions, considering three heating schemes, each with eleven randomly distributed hotspots. The thermohydraulic performance was assessed by calculating temperature non-uniformity, thermal resistance, and pumping power. A correlation was established using the cell size and cell wall thickness of a unit cell of gyroid TPMS to calculate its hydraulic diameter. The analysis revealed that the enhanced thermal performance of the GHS design can be attributed to its intricate and convoluted flow structure, along with a significantly large heat transfer surface area. However, these same factors contribute to a notably high-pressure drop. Compared to the PHS design, the GHS design showed better thermal performance at all the selected porosities and flow rates, albeit with higher pumping powers. The GHS design showed improvement in the thermal performance as the porosity decreased. Investigation under heterogeneous heating conditions showed substantially lower temperatures at the hotspots in the GHS design, along with reduced temperature variation among them. The study’s findings provide valuable insight into the advantages and drawbacks of gyroid TPMS structure for their application in electronic cooling.

Host-induced cell wall remodeling impairs opsonophagocytosis of Staphylococcus aureus by neutrophils.

Understanding how bacteria adapt to the host environment is critical in determining fundamental mechanisms of immune evasion, pathogenesis, and the identification of targets for new therapeutic approaches. Previous work demonstrated that Staphylococcus aureus remodels its cell envelope in response to host factors and we hypothesized that this may affect recognition by antibodies and thus killing by immune cells. As expected, incubation of S. aureus in human serum resulted in rapid binding of antibodies. However, as bacteria adapted to the serum, the increase in cell wall thickness resulted in a significant reduction in exposure of bound antibodies. This reduced antibody exposure, in turn, led to reduced killing by human neutrophils. Importantly, while antibodies bound to some cell surface structures became obscured, this was not the case for those bound to wall teichoic acid, which may have important implications for vaccine design.

Functional profiling of CHAP domain-containing peptidoglycan hydrolases of Staphylococcus aureus USA300 uncovers potential targets for anti-staphylococcal therapies

The bacterial pathogen Staphylococcus aureus employs a thick cell wall for protection against physical and chemical insults. This wall requires continuous maintenance to ensure strength and barrier integrity, but also to permit bacterial growth and division. The main cell wall component is peptidoglycan. Accordingly, the bacteria produce so-called peptidoglycan hydrolases (PGHs) that cleave glycan strands to facilitate growth, cell wall remodelling, separation of divided cells and release of exported proteins into the extracellular milieu. A special class of PGHs contains so-called ‘cysteine, histidine-dependent amidohydrolase/peptidase’ (CHAP) domains. In the present study, we profiled the roles of 11 CHAP PGHs encoded by the core genome of S. aureus USA300 LAC. Mutant strains lacking individual CHAP PGHs were analysed for growth, cell morphology, autolysis, and invasion and replication inside human lung epithelial cells. The results show that several investigated CHAP PGHs contribute to different extents to extracellular and intracellular growth and replication of S. aureus, septation of dividing cells, daughter cell separation once the division process is completed, autolysis and biofilm formation. In particular, the CHAP PGHs Sle1 and SAUSA300_2253 control intracellular staphylococcal replication and the resistance to β-lactam antibiotics like oxacillin. This makes the S. aureus PGHs in general, and the Sle1 and SAUSA300_2253 proteins in particular, attractive targets for future prophylactic or therapeutic anti-staphylococcal interventions. Alternatively, these cell surface-exposed enzymes, or particular domains of these enzymes, could be applied in innovative anti-staphylococcal therapies.

Quantitative Trait Loci Mapping and Candidate Gene Analysis for Fiber Quality Traits in Upland Cotton

Superior fiber quality is one of the most important objectives in cotton breeding. To detect the genetic basis underlying fiber quality, an F2 population containing 413 plants was constructed by crossing Jifeng 914 and Jifeng 173, both of which have superior fiber quality, with Jifeng 173 being better. Five fiber quality traits were investigated in the F2, F2:3, F2:4, and F2:5 populations. Quantitative trait loci (QTL) mapping was conducted based on a high-density genetic map containing 11,488 single nucleotide polymorphisms (SNPs) and spanning 4202.12 cM in length. Transgressive segregation patterns and complex correlations in the five tested traits were observed. A total of 108 QTLs were found, including 13 major effect QTLs that contributed more than 10% toward phenotypic variation (PV) and 9 stable QTLs that could be repeatedly mapped in different generations. Chromosome A7 contained 12 QTL, ranking the first. No QTL was found on chromosomes D1 and D11. Two QTLs could be repeatedly detected in three populations, including qFL-D3-2 in F2, F2:4, and F2:5 with 9.18–21.45% of PV and qFS-A11-1 in F2:3, F2:4, and F2:5 with 6.05–10.41% of PV. Another seven stable QTLs could be detected in two populations, including four major effect QTLs: qFL-A12-3, qFS-D10-2, qMC-D6-2, and qMC-D8-1. Fourteen QTL-overlapping regions were found, which might explain the complex correlations among the five phenotypic traits. Four regions on chromosome A11, D3, D6, and D10 covered by both stable and major effect QTLs are promising for further fine mapping. The genomic regions of the two QTLs detected in three populations and the four major effect QTLs contain 810 genes. Gene functional analysis revealed that the annotated genes are mainly involved in protein binding and metabolic pathways. Fifteen candidate genes in the qFL-D3-2 region are highly expressed in fiber or ovules during fiber initiation, elongation, secondary cell wall thickening, or maturation stages. qRT-PCR revealed that Ghir_D03G005440.1 and Ghir_D03G011310.1 may play a role in promoting fiber initiation, while Ghir_D03G006470.1 may be beneficial for promoting fiber elongation. This study provides more information for revealing the molecular genetic basis underlying cotton fiber quality.

Reduced mesophyll conductance under chronic O3 exposure in poplar reflects thicker cell walls and increased subcellular diffusion pathway lengths according to the anatomical model.

Ozone (O3) is one of the most harmful and widespread air pollutants, affecting crop yield and plant health worldwide. There is evidence that O3 reduces the major limiting factor of photosynthesis, namely CO2 mesophyll conductance (gm), but there is little quantitative information of O3-caused changes in key leaf anatomical traits and their impact on gm. We exposed two O3-responsive clones of the economically important tree species Populus × canadensis Moench to 120 ppb O3 for 21 days. An anatomical diffusion model within the leaf was used to analyse the entire CO2 diffusion pathway from substomatal cavities to carboxylation sites and determine the importance of each structural and subcellular component as a limiting factor. gm decreased substantially under O3 and was found to be the most important limitation of photosynthesis. This decrease was mostly driven by an increased cell wall thickness and length of subcellular diffusion pathway caused by altered interchloroplast spacing and chloroplast positioning. By contrast, the prominent leaf integrative trait leaf dry mass per area was neither affected nor related to gm under O3. The observed relationship between gm and anatomy, however, was clone-dependent, suggesting that mechanisms regulating gm may differ considerably between closely related plant lines. Our results confirm the need for further studies on factors constraining gm under stress conditions.

Enhanced lignin and cellulose metabolism promote cell wall synthesis and growth of wild soybean HRA under alkali stress.

Soil salinization adversely threatens plant survival and food production globally. The mobilization of storage reserves in cotyledons and establishment of the hypocotyl/root axis (HRA) structure and function are crucial to the growth of dicotyledonous plants during the post-germination growth period. Here, we report the adaptive mechanisms of wild and cultivated soybeans in response to alkali stress in soil during the post-germination growth period. Diferences in physiological parameters, microstructure, and the types, amounts and metabolic pathways of small molecule metabolites and gene expression were compared and multi-omics integration analysis was performed between wild and cultivated soybean under sufcient and artifcially simulated alkali stress during the post-germination growth period in this study. Structural analysis showed that the cell wall thickness of wild soybean under alkali stress increased, whereas cultivated soybeans were severely damaged. A comprehensive analysis of small molecule metabolites and gene expression revealed that protein breakdown in wild soybean cotyledons under alkali stress was enhanced, and transport of amino acids and sucrose increased. Additionally, lignin and cellulose synthesis in wild soybean HRA under alkali stress were enhanced. verall, protein decomposition and transport of amino acids and sucrose increased in wild soybean cotyledons under alkali stress, which in turn, promotes HRA growth. Similarly, lignin and cellulose synthesis in wild soybean HRA enhanced, which subsequently, enhanced cell wall synthesis, thereby maintaining the stability and functionality of HRA under alkali stress. This study presents important practical implications for the utilization of wild plant resources and sustainable development of agriculture.

Anatomical characteristic and fiber morphology of fibrovascular bundle of Indonesian nipa (Nypa fruticans) frond

Nipa (Nypa Fruticans) is a palm tree that grows in wetlands and mangroves. Nipa fronds possess lignocellulose and hold the potential as a viable source for producing composite boards, pulp, and paper. This research aims to identify the anatomical and morphological characteristics of nipah fronds fiber, especially in the fibrovascular bundle. Nipa fronds were observed in the radial and longitudinal directions. There are four zones in the radial direction, consisting of the outer zone (convex and concave), middle zone, and inner zone. The longitudinal positions consist of the bottom, intermediate, and upper. Anatomical characteristics were observed using a light microscope focused on the fibrovascular bundle's characteristics. Fiber morphology was measured at each position with 20 repetitions of each measurement. The results showed that the number of FVB increased from the outer zone, especially convex towards the middle and inner zone. Thus, the outer fronds are denser than the inner zone. Based on observations of fiber morphology, the concave (radial) zone in the intermediate position (longitudinal) has the longest fiber compared to the other parts. Meanwhile, the cell wall thickness is greatest at the bottom of the concave zone. The widest lumen diameter is the convex zone at the bottom position. This research can conclude that the FVB of nipa palm fronds, both longitudinal and radial, are included in quality class III, which is good enough to be used as raw material for pulp and paper.