E93 is indispensable for reproduction in ametabolous and hemimetabolous insects.

Ecdysone-induced protein 93 (E93), known as the 'adult-specifier' transcription factor in insects, triggers metamorphosis in both hemimetabolous and holometabolous insects. Although E93 is conserved in ametabolous insects, its spatiotemporal expression and physiological function remain poorly understood. In this study, we first discover that, in the ametabolous firebrat Thermobia domestica, the previtellogenic ovary exhibits cyclically high E93 expression, and E93 mRNA is broadly distributed in previtellogenic ovarioles. E93 homozygous mutant females of T. domestica exhibit severe fecundity deficiency due to impaired previtellogenic development of the ovarian follicles, likely because E93 induces the expression of genes involved in ECM (extracellular matrix)-receptor interactions during previtellogenesis. Moreover, we reveal that in the hemimetabolous cockroach Blattella germanica, E93 similarly promotes previtellogenic ovarian development. In addition, E93 is also essential for vitellogenesis that is necessary to guarantee ovarian maturation and promotes the vitellogenesis-previtellogenesis switch in the fat body of adult female cockroaches. Our findings deepen the understanding of the roles of E93 in controlling reproduction in insects, and of E93 expression and functional evolution, which are proposed to have made crucial contributions to the origin of insect metamorphosis.

MvGraphDTA: multi-view-based graph deep model for drug-target affinity prediction by introducing the graphs and line graphs.

BACKGROUND: Accurately identifying drug-target affinity (DTA) plays a pivotal role in drug screening, design, and repurposing in pharmaceutical industry. It not only reduces the time, labor, and economic costs associated with biological experiments but also expedites drug development process. However, achieving the desired level of computational accuracy for DTA identification methods remains a significant challenge. RESULTS: We proposed a novel multi-view-based graph deep model known as MvGraphDTA for DTA prediction. MvGraphDTA employed a graph convolutional network (GCN) to extract the structural features from original graphs of drugs and targets, respectively. It went a step further by constructing line graphs with edges as vertices based on original graphs of drugs and targets. GCN was also used to extract the relationship features within their line graphs. To enhance the complementarity between the extracted features from original graphs and line graphs, MvGraphDTA fused the extracted multi-view features of drugs and targets, respectively. Finally, these fused features were concatenated and passed through a fully connected (FC) network to predict DTA. CONCLUSIONS: During the experiments, we performed data augmentation on all the training sets used. Experimental results showed that MvGraphDTA outperformed the competitive state-of-the-art methods on benchmark datasets for DTA prediction. Additionally, we evaluated the universality and generalization performance of MvGraphDTA on additional datasets. Experimental outcomes revealed that MvGraphDTA exhibited good universality and generalization capability, making it a reliable tool for drug-target interaction prediction.

Juvenile hormone signaling is indispensable for late embryogenesis in ametabolous and hemimetabolous insects.

BACKGROUND: Juvenile hormone (JH) is an insect-exclusive hormone involved in regulating diverse aspects of insect physiology, and the evolution of its diverse function is widely interesting. Studying embryogenesis in basal wingless insects is important to understand the functional evolution of JH; however, experimental studies in this regard are scarce. In this study, we conducted CRISPR/Cas9-mediated knockout (KO) of genes involved in JH biosynthesis and signaling cascades in the ametabolous firebrat, Thermobia domestica. Additionally, we investigated whether the primitive action of JH is conserved in the hemimetabolous cricket, Gryllus bimaculatus. RESULTS: We observed that KO of JHAMT, CYP15A1, Met, and Kr-h1 resulted in embryonic lethality in T. domestica. Deprivation of JH or JH signaling arrested the progression of extraembryonic fluid resorption after dorsal closure and hatching, which is consistent with the gene expression pattern showing high Kr-h1 expression in the late embryos of T. domestica. The embryos deficient in JH signaling displayed wrinkled and weak legs. Comparative transcriptome analysis revealed that JH signaling promotes embryonic leg maturation through inducing energy supply and muscle activity, as validated by transmission electron microscopy (TEM). In addition, JH signaling exhibited similar embryonic effects in G. bimaculatus. CONCLUSIONS: This study reveals the indispensable role of JH signaling in facilitating the maturation of terminal tissues during late embryogenesis, as demonstrated by the regulation of leg development, in ametabolous and hemimetabolous insects. These findings further indicate that the embryonic functions of JH evolved earlier than its anti-metamorphic functions during postembryonic development.

Application of a single-cell-RNA-based biological-inspired graph neural network in diagnosis of primary liver tumors.

Single-cell technology depicts integrated tumor profiles including both tumor cells and tumor microenvironments, which theoretically enables more robust diagnosis than traditional diagnostic standards based on only pathology. However, the inherent challenges of single-cell RNA sequencing (scRNA-seq) data, such as high dimensionality, low signal-to-noise ratio (SNR), sparse and non-Euclidean nature, pose significant obstacles for traditional diagnostic approaches. The diagnostic value of single-cell technology has been largely unexplored despite the potential advantages. Here, we present a graph neural network-based framework tailored for molecular diagnosis of primary liver tumors using scRNA-seq data. Our approach capitalizes on the biological plausibility inherent in the intercellular communication networks within tumor samples. By integrating pathway activation features within cell clusters and modeling unidirectional inter-cellular communication, we achieve robust discrimination between malignant tumors (including hepatocellular carcinoma, HCC, and intrahepatic cholangiocarcinoma, iCCA) and benign tumors (focal nodular hyperplasia, FNH) by scRNA data of all tissue cells and immunocytes only. The efficacy to distinguish iCCA from HCC was further validated on public datasets. Through extending the application of high-throughput scRNA-seq data into diagnosis approaches focusing on integrated tumor microenvironment profiles rather than a few tumor markers, this framework also sheds light on minimal-invasive diagnostic methods based on migrating/circulating immunocytes.

CCDC88C variants are associated with focal epilepsy and genotype-phenotype correlation.

CCDC88C gene, which encodes coiled-coil domain containing 88C, is essential for cell communication during neural development. Variants in the CCDC88C caused congenital hydrocephalus, some accompanied by seizures. In patients with epilepsy without acquired etiologies, we performed whole-exome sequencing (trio-based). Two de novo and two biallelic CCDC88C variants were identified in four cases with focal (partial) epilepsy. These variants did not present or had low frequencies in the gnomAD populations and were predicted to be damaging by multiple computational algorithms. Patients with de novo variants presented with adult-onset epilepsy, whereas patients with biallelic variants displayed infant-onset epilepsy. They all responded well to anti-seizure medications and were seizure-free. Further analysis showed that de novo variants were located at crucial domains, whereas one paired biallelic variants were located outside the crucial domains, and the other paired variant had a non-classical splicing and a variant located at crucial domain, suggesting a sub-molecular effect. CCDC88C variants associated with congenital hydrocephalus were all truncated, whereas epilepsy-associated variants were mainly missense, the proportion of which was significantly higher than that of congenital hydrocephalus-associated variants. CCDC88C is potentially associated with focal epilepsy with favorable outcome. The underlying mechanisms of phenotypic variation may correlation between genotype and phenotype.

Simultaneous improvement of fiber yield and quality in upland cotton (Gossypium hirsutum L.) by integration of auxin transport and synthesis.

Cotton is a widely planted commercial crop in the world. Enhancing fiber yield and quality is a long-term goal for cotton breeders. Our previous work has demonstrated that fine promotion of auxin biosynthesis in ovule epidermis, by overexpressing FBP7pro::iaaM, has a significant improvement on lint yield and fiber fineness. Lately, transgenic cottons overexpressing GhROP6 variants modify mature fiber length by controlling GhPIN3a-mediated polar auxin transport in ovules. Here, this study showed that all these GhROP6-related cottons displayed unsatisfactory agronomic performance in field conditions. Yet extra auxin supply could promote their fiber development, suggesting inadequate auxin supply in the ovules. Thus, these cottons were integrated with enhanced auxin synthesis by crossing with FBP7pro::iaaM cotton. All the transgene-stacked cottons exhibited synergetic effects on cotton yield (seedcotton yield, lint yield, and lint percentage) and quality (length, strength, and micronaire). Notably, comparing to the FBP7pro::iaaM background, the transgene-stacked cotton co-expressing FBP7pro::iaaM and CA-ghrop6 (constitutively active GhROP6) exhibited a 12.6% increase in seedcotton yield and a 19.0% increase in lint yield over a three-year field trial, and simultaneously resulted in further improvement on fiber length, strength, and micronaire. Collectively, our data provide a potential strategy for genetic improvement on cotton fiber yield and quality. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-024-01500-w.

GhMYB52 Like: A Key Factor That Enhances Lint Yield by Negatively Regulating the Lignin Biosynthesis Pathway in Fibers of Upland Cotton (Gossypium hirsutum L.).

In the context of sustainable agriculture and biomaterial development, understanding and enhancing plant secondary cell wall formation are crucial for improving crop fiber quality and biomass conversion efficiency. This is especially critical for economically important crops like upland cotton (Gossypium hirsutum L.), for which fiber quality and its processing properties are essential. Through comprehensive genome-wide screening and analysis of expression patterns, we identified a particularly high expression of an R2R3 MYB transcription factor, GhMYB52 Like, in the development of the secondary cell wall in cotton fiber cells. Utilizing gene-editing technology to generate a loss-of-function mutant to clarify the role of GhMYB52 Like, we revealed that GhMYB52 Like does not directly contribute to cellulose synthesis in cotton fibers but instead represses a subset of lignin biosynthesis genes, establishing it as a lignin biosynthesis inhibitor. Concurrently, a substantial decrease in the lint index, a critical measure of cotton yield, was noted in parallel with an elevation in lignin levels. This study not only deepens our understanding of the molecular mechanisms underlying cotton fiber development but also offers new perspectives for the molecular improvement of other economically important crops and the enhancement of biomass energy utilization.

Downregulation of the GhROD1 Gene Improves Cotton Fiber Fineness by Decreasing Acyl Pool Saturation, Stimulating Small Heat Shock Proteins (sHSPs), and Reducing H2O2 Production.

Cotton fiber is one of the most important natural fiber sources in the world, and lipid metabolism plays a critical role in its development. However, the specific role of lipid molecules in fiber development and the impact of fatty acid alterations on fiber quality remain largely unknown. In this study, we demonstrate that the downregulation of GhROD1, a gene encoding phosphatidylcholine diacylglycerol cholinephosphotransferase (PDCT), results in an improvement of fiber fineness. We found that GhROD1 downregulation significantly increases the proportion of linoleic acid (18:2) in cotton fibers, which subsequently upregulates genes encoding small heat shock proteins (sHSPs). This, in turn, reduces H2O2 production, thus delaying secondary wall deposition and leading to finer fibers. Our findings reveal how alterations in linoleic acid influence cellulose synthesis and suggest a potential strategy to improve cotton fiber quality by regulating lipid metabolism pathways.

[Study on mitigating effect and mechanism of Cichorium glandulosum n-butanol extraction site on CCl_4-induced chronic liver injury in rats].

This study aims to investigate the mitigating effect and mechanism of Cichorium glandulosum n-butanol extraction site(CGE) on the disease in carbon tetrachloride(CCl_4)-induced chronic liver injury model in rats. A chronic liver injury model was constructed by subcutaneous injection of CCl_4 olive oil solution, and after four weeks of CGE treatment, serum levels of aspartate aminotransferase(AST), alanine aminotransferase(ALT), alkaline phosphatase(AKP), hydroxyproline(HYP), interleukin-4(IL-4), interleukin-6(IL-6), malondialdehyde(MDA), superoxide dismutase(SOD), and tumor necrosis factor-α(TNF-α) were detected. Liver tissue was processed by hematoxylin-eosin(HE) staining and Masson staining to observe the structure of the rat liver. qPCR and Western blot were used to examine the expression of transforming growth factor-ß1(TGF-ß1)/small mothers against decapentaplegic(Smad), Toll-like receptor 4(TLR4), α-smooth muscle actin(α-SMA), and fibronectin(Fn) in rat liver tissue and hepatic stellate-T6(HSC-T6) and evaluate the inhibitory effect of CGE on HSC activation. The results showed that CGE could significantly reduce the serum levels of AST, ALT, AKP, HYP, and affect the levels of related inflammatory indexes including IL-4, IL-6, and TNF-α, and MDA in CCl_4-induced chronic liver injury in rats and had no effect on SOD activity, which could delay the process of liver injury, alleviate the hepatic collagen deposition and inflammatory infiltration, and had significant efficacy in mitigating chronic liver injury in rats. CGE could inhibit α-SMA and TLR4 protein expression in the liver tissue and reverse the increased TGF-ß1/Smad, Fn, and TLR4-related expression in HSC-T6 in vitro. The above results indicated that CGE exerted hepatoprotective effects in rats by inhibiting HSC activation and alleviated CCl_4-induced chronic liver injury in rats and could ameliorate inflammatory response and slight liver fibrosis in rat liver tissue. Its pharmacodynamic mechanism might be related to TGF-ß1/Smad and TLR4-related expression.

Tailored Exfoliation of Polymeric Carbon Nitride for Photocatalytic H2O2 Production and CH4 Valorization Mediated by O2 Activation.

The exfoliation of bulk C3N4 (BCN) into ultrathin layered structure is an effective strategy to boost photocatalytic efficiency by exposing interior active sites and accelerating charge separation and transportation. Herein, we report a novel nitrate anion intercalation-decomposition (NID) strategy that is effective in peeling off BCN into few-layer C3N4 (fl-CN) with tailored thickness down to bi-layer. This strategy only involves hydrothermal treatment of BCN in diluted HNO3 aqueous solution, followed by pyrolysis at various temperatures. The decomposition of the nitrate anions not only exfoliates BCN and changes the band structure, but also incorporates oxygen species onto fl-CN, which is conducive to O2 adsorption and hence relevant chemical processes. In photocatalytic O2 reduction under visible light irradiation, the H2O2 production rate over the optimal fl-CN-530 catalyst is 952 µmol g-1 h-1, which is 8.8 times that over BCN. More importantly, under full arc irradiation and in the absence of hole scavenger, CH4 can be photocatalytically oxidized by on-site formed H2O2 and active oxygen species to generate value-added C1 oxygenates with high selectivity of 99.2 % and record-high production rate of 1893 µmol g-1 h-1 among the metal-free C3N4-based photocatalysts.

Poor pretransplantation minimal residual disease clearance as an independent prognostic risk factor for survival in myelodysplastic syndrome with excess blasts: A multicenter, retrospective cohort study.

BACKGROUND: Minimal residual disease (MRD) is an important prognostic factor for survival in adults with acute leukemia. The role of pretransplantation MRD status in myelodysplastic syndrome with excess blasts (MDS-EB) is unknown. This study retrospectively analyzed the relationship between pretransplantation MRD status and long-term survival. MATERIALS AND METHODS: Patients with MDS-EB who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) from March 5, 2005, to November 8, 2020, were included. The relationship between pretransplantation MRD status and long-term survival was analyzed using univariate and multivariate logistic regression models. RESULTS: Of 220 patients with MDS-EB who underwent allo-HSCT, 198 were eligible for inclusion in this multicenter, retrospective cohort study. Complete remission was attained in 121 (61.1%) patients, and 103 patients underwent detection of MRD pretransplantation, with 67 patients being MRD-positive and 36 patients being MRD-negative. The median follow-up time was 16 months, the median age was 41 years (6-65 years), and 58% of the patients were men. The 3-year disease-free survival (DFS) and overall survival (OS) probabilities for all patients were 70.1% and 72.9%, respectively. For patients in complete remission, the 3-year DFS and OS probabilities were 72.2% and 74.8%, respectively. Further analysis found that the 3-year DFS rates of MRD-negative and MRD-positive patients were 85.6% and 66.5% (p = .045), respectively, whereas the 3-year OS rates were 91.3% and 66.4% (p = .035), respectively. Univariate and multivariate analyses showed that poor pretransplantation MRD clearance was an independent prognostic risk factor for DFS and OS. CONCLUSION: Poor pretransplantation MRD clearance is an independent prognostic risk factor for long-term survival after allo-HSCT for patients with MDS-EB. PLAIN LANGUAGE SUMMARY: Poor minimal residual disease clearance pretransplanation is an independent prognostic risk factor for long-term survival after allogeneic hematopoietic stem cell transplantation for patients with myelodysplastic syndrome with excess blasts.

GhROP6 GTPase modulates auxin accumulation in cotton fibers by regulating cell-specific GhPIN3a localization.

PIN-FORMED- (PIN) mediated polar auxin transport plays a predominant role in most auxin-triggered organogenesis in plants. Global control of PIN polarity at the plasma membrane contributes to the essential establishment of auxin maxima in most multicellular tissues. However, establishment of auxin maxima in single cells is poorly understood. Cotton fibers, derived from ovule epidermal cells by auxin-triggered cell protrusion, provide an ideal model to explore the underlying mechanism. Here, we report that cell-specific degradation of GhPIN3a, which guides the establishment of the auxin gradient in cotton ovule epidermal cells, is associated with the preferential expression of GhROP6 GTPase in fiber cells. In turn, GhROP6 reduces GhPIN3a abundance at the plasma membrane and facilitates intracellular proteolysis of GhPIN3a. Overexpression and activation of GhROP6 promote cell elongation, resulting in a substantial improvement in cotton fiber length.

Regulation of PIN-FORMED Protein Degradation.

Auxin action largely depends on the establishment of auxin concentration gradient within plant organs, where PIN-formed (PIN) auxin transporter-mediated directional auxin movement plays an important role. Accumulating studies have revealed the need of polar plasma membrane (PM) localization of PIN proteins as well as regulation of PIN polarity in response to developmental cues and environmental stimuli, amongst which a typical example is regulation of PIN phosphorylation by AGCVIII protein kinases and type A regulatory subunits of PP2A phosphatases. Recent findings, however, highlight the importance of PIN degradation in reestablishing auxin gradient. Although the underlying mechanism is poorly understood, these findings provide a novel aspect to broaden the current knowledge on regulation of polar auxin transport. In this review, we summarize the current understanding on controlling PIN degradation by endosome-mediated vacuolar targeting, autophagy, ubiquitin modification and the related E3 ubiquitin ligases, cytoskeletons, plant hormones, environmental stimuli, and other regulators, and discuss the possible mechanisms according to recent studies.

Primary repair for concurrent bilateral intertrochanteric fracture and femoral head necrosis with prolonged shank biologic total hip replacement: A case report and surgical techniques.

For the treatment of an intertrochanteric fracture combined with femoral head necrosis in middle-age patients, it has been controversial whether to perform fracture reduction and fixation first then total hip replacement, or direct total hip replacement. We present a rare case of 53-year-old male patient suffered from bilateral intertrochanteric fracture caused by a road traffic injury. The patient had a history of femoral head necrosis for eight years, and the Harris score was 30. We performed total hip replacement with prolonged biologic shank prostheses for primary repair. One year after the surgery, nearly full range of motion was achieved without instability (active flexion angle of 110°, extension angle of 20°, adduction angle of 40°, abduction angle of 40°, internal rotation angle of 25°, and external rotation angle of 40°). The Harris score was 85. For the middle-aged patient with unstable intertrochanteric fractures and osteonecrosis of the femoral head, we can choose primary repair for concurrent bilateral intertrochanteric fracture and femoral head necrosis with prolonged shank biologic total hip replacement.

Research Progress on Microbial Community Succession in the Postmortem Interval Estimation.

The postmortem interval (PMI) estimation is a key and difficult point in the practice of forensic medicine, and forensic scientists at home and abroad have been searching for objective, quantifiable and accurate methods of PMI estimation. With the development and combination of high-throughput sequencing technology and artificial intelligence technology, the establishment of PMI model based on the succession of the microbial community on corpses has become a research focus in the field of forensic medicine. This paper reviews the technical methods, research applications and influencing factors of microbial community in PMI estimation explored by using high-throughput sequencing technology, to provide a reference for the related research on the use of microbial community to estimate PMI.

Synthetic K+ Channels Constructed by Rebuilding the Core Modules of Natural K+ Channels in an Artificial System.

Different types of natural K+ channels share similar core modules and cation permeability characteristics. In this study, we have developed novel artificial K+ channels by rebuilding the core modules of natural K+ channels in artificial systems. All the channels displayed high selectivity for K+ over Na+ and exhibited a selectivity sequence of K+ ≈Rb+ during the transport process, which is highly consistent with the cation permeability characteristics of natural K+ channels. More importantly, these artificial channels could be efficiently inserted into cell membranes and mediate the transmembrane transport of K+ , disrupting the cellular K+ homeostasis and eventually triggering the apoptosis of cells. These findings demonstrate that, by rebuilding the core modules of natural K+ channels in artificial systems, the structures, transport behaviors, and physiological functions of natural K+ channels can be mimicked in synthetic channels.

Enhanced autophagy promotes radiosensitivity by mediating Sirt1 downregulation in RM-1 prostate cancer cells.

Autophagy is a double-edged sword that affects tumor progression by promoting cell survival or death depending on different living contexts. The concrete mechanism by which autophagy modulates the efficacy of radiotherapy for prostate cancer (PC) remains unclear. We exposed RM-1 PC cells to X-ray and explored the role of autophagy in radiation injury. Our results showed increased apoptosis and autophagy levels in RM-1 cells after radiation. Pharmacological inhibition of autophagy by chloroquine significantly mitigated radiation-induced apoptosis, while the enhancement of autophagy by rapamycin aggravated apoptosis. Sirt1, a member of sirtuin family, deacetylates various transcription factors to trigger cell survival in response to radiation injury. We found that radiation led to Sirt1 downregulation, which was reversed by the inhibition of autophagy. On the contrary, enhanced autophagy further diminished protein level of Sirt1. Notably, overexpression of Sirt1 by plasmid significantly alleviated radiation-induced apoptosis, but silenced Sirt1 by siRNA further induced apoptosis, indicating the radioprotective effect of Sirt1 on RM-1 cells. In summary, our findings suggested that autophagy-mediated Sirt1 downregulation might be a promising therapeutic target for PC.

Characterization of a fungal competition factor: Production of a conidial cell-wall associated antifungal peptide.

Competition is one of the fundamental driving forces of natural selection. Beauveria bassiana is a soil and plant phylloplane/root fungus capable of parasitizing insect hosts. Soil and plant environments are often enriched with other fungi against which B. bassiana competes for survival. Here, we report an antifungal peptide (BbAFP1), specifically expressed and localized to the conidial cell wall and is released into the surrounding microenvironment inhibiting growth of competing fungi. B. bassiana strains expressing BbAFP1, including overexpression strains, inhibited growth of Alternaria brassicae in co-cultured experiments, whereas targeted gene deletion of BbAFP1 significantly decreased (25%) this inhibitory effect. Recombinant BbAFP1 showed chitin and glucan binding abilities, and growth inhibition of a wide range of phytopathogenic fungi by disrupting membrane integrity and eliciting reactive oxygen species (ROS) production. A phenylalanine residue (F50) contributes to chitin binding and antifungal activity, but was not required for the latter. Expression of BbAFP1 in tomato resulted in transgenic plants with enhanced resistance to plant fungal pathogens. These results highlight the importance of fungal competition in shaping primitive competition strategies, with antimicrobial compounds that can be embedded in the spore cell wall to be released into the environment during the critical initial phases of germination for successful growth in its environmental niche. Furthermore, these peptides can be exploited to increase plant resistance to fungal pathogens.

Carpel-specific down-regulation of GhCKXs in cotton significantly enhances seed and fiber yield.

Cytokinin is considered to be an important driver of seed yield. To increase the yield of cotton while avoiding the negative consequences caused by constitutive overproduction of cytokinin, we down-regulated specifically the carpel genes for cytokinin oxidase/dehydrogenase (CKX), a key negative regulator of cytokinin levels, in transgenic cotton. The carpel-specific down-regulation of CKXs significantly enhanced cytokinin levels in the carpels. The elevated cytokinin promoted the expression of carpel- and ovule-development-associated genes, GhSTK2, GhAG1, and GhSHP, boosting ovule formation and thus producing more seeds in the ovary. Field experiments showed that the carpel-specific increase of cytokinin significantly increased both seed yield and fiber yield of cotton, without resulting in detrimental phenotypes. Our study details the regulatory mechanism of cytokinin signaling for seed development, and provides an effective and feasible strategy for yield improvement of seed crops.

Microtubules play a crucial role in regulating actin organization and cell initiation in cotton fibers.

KEY MESSAGE: Dynamic organization of actin and microtubule cytoskeletons directs a distinct expansion behavior of cotton fiber initiation from cell elongation. Cotton fibers are highly elongated single cells derived from the ovule epidermis. Although actin and microtubule (MT) cytoskeletons have been implicated in cell elongation and secondary wall deposition, their roles in fiber initiation is poorly understood. Here, we used fluorescent probes and pharmacological approaches to study the roles of these cytoskeletal components during cotton fiber initiation. Both cytoskeletons align along the growth axis in initiating fibers. The dorsal view of ovules shows that unlike the fine actin filaments (AFs) in nonfiber cells, the AFs in fiber cells are dense and bundled. MTs are randomized in fiber cells and well-ordered in nonfiber cells. The pharmacological experiments revealed that the depolymerization of AFs and MTs assisted fiber initiation. Both AF stabilization and depolymerization inhibited fiber elongation. In contrast, the proper depolymerization of MTs promoted cell elongation, although the MT-stabilizing drug consistently resulted in a negative effect. Notably, we found that the organization of AFs was correlated with MT dynamics. Stabilizing the MTs by taxol treatment promoted the formation of AF bundles (in fiber initials) and transversely aligned AFs (in elongating fibers), whereas depolymerizing the MTs by oryzalin treatment promoted the fragmentation of AFs. Collectively, our data indicates that MTs plays a crucial role in regulating AF organization and early development of cotton fibers.