Cell Wall Biosynthesis Research Articles

Genome-wide characterization of the Rho family in cotton provides insights into fiber development

BackgroundCotton is the source of natural fibers globally, fulfilling 90% of the textile industry's requirements. However, fiber development is a complex biological process comprising four stages. Fiber develops from a single cell, and cell elongation is a vital process in fiber development. Therefore, it is pertinent to understand and exploit mechanisms underlying cell elongation during fiber development. A previous report about cell division control protein 42 (CDC-42) with its key role in cell elongation in eukaryotes inspired us to explore its homologs Rho GTPases for understanding of cell elongation during cotton fiber development.ResultWe classified 2 066 Rho proteins from 8 Gossypium species into 5 and 8 groups within A and D sub-genomes, respectively. Asymmetric evolution of Rho members was observed among five tetraploids. Population fixation statistics between two short and long fiber genotypes identified highly diverged regions encompassing 34 Rho genes in G. hirustum, and 31 of them were retained through further validation by genome wide association analysis (GWAS). Moreover, a weighted gene co-expression network characterized genome-wide expression patteren of Rho genes based on previously published transcriptome data. Twenty Rho genes from five modules were identified as hub genes which were potentially related to fiber development. Interaction networks of 5 Rho genes based on transcriptional abundance and gene ontology (GO) enrichment emphasized the involvement of Rho in cell wall biosynthesis, fatty acid elongation, and other biological processes.ConclusionOur study characterized the Rho proteins in cotton, provided insights into the cell elongation of cotton fiber and potential application in cotton fiber improvement.

Phosphoglucose Isomerase Is Important for Aspergillus fumigatus Cell Wall Biogenesis.

ABSTRACTAspergillus fumigatus is a devastating opportunistic fungal pathogen causing hundreds of thousands of deaths every year. Phosphoglucose isomerase (PGI) is a glycolytic enzyme that converts glucose-6-phosphate to fructose-6-phosphate, a key precursor of fungal cell wall biosynthesis. Here, we demonstrate that the growth of A. fumigatus is repressed by the deletion of pgi, which can be rescued by glucose and fructose supplementation in a 1:10 ratio. Even under these optimized growth conditions, the Δpgi mutant exhibits severe cell wall defects, retarded development, and attenuated virulence in Caenorhabditis elegans and Galleria mellonella infection models. To facilitate exploitation of A. fumigatus PGI as an antifungal target, we determined its crystal structure, revealing potential avenues for developing inhibitors, which could potentially be used as adjunctive therapy in combination with other systemic antifungals.

A Mechanistic Study of the Antibacterial Activity of Phytoconstituents of Pyracantha crenulata by Using Molecular Docking Studies

Background: Bacteria cause various infections and are a threat to the health system. This threat is increased due to the resistance of bacteria towards antibacterial drugs. Plants are an important source of drugs including antibacterial agents. Pyracantha crenulata is one important plant known for its different medicinal uses. It contains different phytoconstituents responsible for its medicinal properties. In cholera, ToxT (PDB ID: 3GBG) regulates the expression of virulence factors in Vibrio cholerae. FtsZ (PDB ID: 6RVN) is a protein involved in cell division and septal wall synthesis in bacteria. MurA (PDB ID: 3SWQ) is critical for the biosynthesis of the bacterial cell wall. Flavin mononucleotide (FMN) (PDB ID: 3F2Q) is involved in the biosynthesis and transport of several protein cofactors. In most of the studies on phytoconstituents, the mechanism of action is not described. Therefore, in this study, the above target proteins were selected and specific target inhibitors were used as standard drugs. In light of the above-mentioned facts, we have proposed a mechanism of antibacterial action of phytoconstituents of Pyracantha crenulata based on molecular docking studies. Objective: To propose a mechanism of antibacterial action of phytoconstituents of Pyracantha crenulata based on molecular docking studies. Methods: Molecular docking studies of phytoconstituents of Pyracantha crenulata were performed using the Maestro 12.8 module of Schrodinger software Results: Molecular docking results indicated that many constituents including rutin and phloridzin had better dock scores than standard drugs against different antibacterial targets. Conclusion: From the molecular docking, different constituents may act as good inhibitors of different proteins like phloridzin may act as potent inhibitors of 3GBG, 6RVN, and 3SWQ, which can be used further for the development of new antibacterial agents

Caging pyrophosphate structure blocks the cell wall synthesis to kill bacteria without detectable resistance

The increasing spread of antimicrobial resistance results in untreatable infections, causing thousands of deaths. Thus, it is urgent to find new antibiotics that kill the causative pathogen via a novel action mechanism without detectable resistance. The pyrophosphate structures of UDP-MurNAc-pentapeptide, lipid I, and lipid II in bacteria cytoplasm are highly conserved but play a key role in bacterial wall synthesis and is a promising target for antibiotics. However, to date, no attempt to target pyrophosphate has been made to kill bacteria. Here, we found that a synthetic cage, denoted as PZn2020, can tightly cage pyrophosphate structures blocking transport of lipid and the biosynthesis of cell wall to kill bacteria. It exhibits sub-μg activity against all gram-negative and gram-positive bacteria tested and avoids detectable resistance with low host toxicity. Such a caging pyrophosphate strategy suggests a path towards developing antibiotics with a new mechanism that is likely to avoid the development of resistance.

The 1, 2-ethylenediamine SQ109 protects against tuberculosis by promoting M1 macrophage polarization through the p38 MAPK pathway

Directly Observed Treatment Short-course (DOTs), is an effective and widely recommended treatment for tuberculosis (TB). The antibiotics used in DOTs, are immunotoxic and impair effector T cells, increasing the risk of re-infections and reactivation. Multiple reports suggest that addition of immune-modulators along with antibiotics improves the effectiveness of TB treatment. Therefore, drugs with both antimicrobial and immunomodulatory properties are desirable. N1-(Adamantan-2-yl)-N2-[(2E)-3,7-dimethylocta-2,6-dien-1-yl]ethane-1,2-diamine (SQ109) is an asymmetric diamine derivative of adamantane, that targets Mycobacterial membrane protein Large 3 (MmpL3). SQ109 dissipates the transmembrane electrochemical proton-gradient necessary for cell-wall biosynthesis and bacterial activity. Here, we examined the effects of SQ109 on host-immune responses using a murine TB model. Our results suggest the pro-inflammatory nature of SQ109, which instigates M1-macrophage polarization and induces protective pro-inflammatory cytokines through the p38-MAPK pathway. SQ109 also promotes Th1 and Th17-immune responses that inhibit the bacillary burden in a murine model of TB. These findings put forth SQ109 as a potential-adjunct to TB antibiotic therapy.

LsNRL4 enhances photosynthesis and decreases leaf angles in lettuce.

SummaryLettuce (Lactuca sativa) is one of the most important vegetables worldwide and an ideal plant for producing protein drugs. Both well‐functioning chloroplasts that perform robust photosynthesis and small leaf angles that enable dense planting are essential for high yields. In this study, we used an F2 population derived from a cross between a lettuce cultivar with pale‐green leaves and large leaf angles to a cultivar with dark‐green leaves and small leaf angles to clone LsNRL4, which encodes an NPH3/RPT2‐Like (NRL) protein. Unlike other NRL proteins in lettuce, the LsNRL4 lacks the BTB domain. Knockout mutants engineered using CRISPR/Cas9 and transgenic lines overexpressing LsNRL4 verified that LsNRL4 contributes to chloroplast development, photosynthesis and leaf angle. The LsNRL4 gene was not present in the parent with pale‐green leaves and enlarged leaf angles. Loss of LsNRL4 results in the enlargement of chloroplasts, decreases in the amount of cellular space allocated to chloroplasts and defects in secondary cell wall biosynthesis in lamina joints. Overexpressing LsNRL4 significantly improved photosynthesis and decreased leaf angles. Indeed, the plant architecture of the overexpressing lines is ideal for dense planting. In summary, we identified a novel NRL gene that enhances photosynthesis and influences plant architecture. Our study provides new approaches for the breeding of lettuce that can be grown in dense planting in the open field or in modern plant factories. LsNRL4 homologues may also be used in other crops to increase photosynthesis and improve plant architecture.

Genome-wide identification of miRNAs and targets associated with cell wall biosynthesis: Differential roles of dlo-miR397a and dlo-miR408-3p during early somatic embryogenesis in longan

The dynamic alterations in cell wall (CW) biosynthesis play an essential role in physiological isolation during the plant somatic embryogenesis (SE). However, the mechanisms underlying the functions of cell wall-associated miRNAs (CW-miRNA) remain poorly understood in plant SE. Here, we have identified 36 distinct candidate miRNAs associated with CW biosynthesis from longan third-generation genome as well as miRNA transcriptome, and modified RLM-RACE validated four distinct miRNA, which specifically targeted four CW-related genes. More importantly, we found that the dlo-miR397a-antagomir significantly enhanced DlLAC7 expression and improved laccase activity. Interestingly, inhibition of dlo-miR397a increased CW lignin deposition and promoted the tightening of protodermal cell by miRNA-mimic technology during early SE. Moreover, overexpression of dlo-miR408–3p (dlo-miR408–3p-agomir) markedly decreased DlLAC12 expression. dlo-miR408–3p-agomir activated rapid cell division, thus promoting the globular embryo (GE) development, which might be due to high DNA synthesis activity in protoepidermal cells, rather than affecting lignin synthesis. The subcellular location also indicated that both DlLAC7 and DlLAC12 proteins were primarily localized in CW and regulated CW biosynthesis. Overall, our findings provided new insight on the molecular regulatory networks comprising various miRNAs associated with cell wall, and established that dlo-miR397a and dlo-miR408–3p played differential roles during early SE in longan. The findings also shed some light on the potential role of miRNA target DlLAC regulating in vivo embryonic development of plant.

Genome-Wide Study of Drug Resistant Mycobacterium tuberculosis and Its Intra-Host Evolution during Treatment.

The emergence of drug resistant Mycobacterium tuberculosis (MTB) strains has become a global public health problem, while, at the same time, there has been development of new antimicrobial agents. The main goals of this study were to determine new variants associated with drug resistance in MTB and to observe which polymorphisms emerge in MTB genomes after anti-tuberculosis treatment. We performed whole-genome sequencing of 152 MTB isolates including 70 isolates as 32 series of pre- and post-treatment MTB. Based on genotypes and phenotypic drug susceptibility, we conducted phylogenetic convergence-based genome-wide association study (GWAS) with streptomycin-, isoniazid-, rifampicin-, ethambutol-, fluoroquinolones-, and aminoglycosides-resistant MTB against susceptible ones. GWAS revealed statistically significant associations of SNPs within Rv2820c, cyp123 and indels in Rv1269c, Rv1907c, Rv1883c, Rv2407, Rv3785 genes with resistant MTB phenotypes. Comparisons of serial isolates showed that treatment induced different patterns of intra-host evolution. We found indels within Rv1435c and ppsA that were not lineage-specific. In addition, Beijing-specific polymorphisms within Rv0036c, Rv0678, Rv3433c, and dop genes were detected in post-treatment isolates. The appearance of Rv3785 frameshift insertion in 2 post-treatment strains compared to pre-treatment was also observed. We propose that the insertion within Rv3785, which was a GWAS hit, might affect cell wall biosynthesis and probably mediates a compensatory mechanism in response to treatment. These results may shed light on the mechanisms of MTB adaptation to chemotherapy and drug resistance formation.

Integrated Physiochemical, Hormonal, and Transcriptomic Analysis Revealed the Underlying Mechanisms for Granulation in Huyou (Citrus changshanensis) Fruit.

Juice sac granulation is a common internal physiological disorder of citrus fruit. In the present study, we compared the physiochemical characteristics and transcriptome profiles of juice sacs in different granulation levels from Huyou fruit (Citrus changshanensis). The accumulation of cell wall components, including the water-soluble pectin, protopectin, cellulose, and lignin, were significantly correlated with the granulation process, resulting in the firmness increase of the juice sac. The in situ labeling of the cell wall components indicated the early accumulation of cellulose and high-methylesterified pectin in the outer layer cells, as well as the late accumulation of lignin in the inner layer cells of the juice sac. Several phytohormones, including auxins, abscisic acids, cytokinins, jasmonic acid, salicylic acid, and/or their metabolites, were positively correlated to the granulation level, indicating an active and complex phytohormones metabolism in the granulation process. Combining the trend analysis by the Mfuzz method and the module-trait correlation analysis by the Weighted Gene Co-expression Network Analysis method, a total of 2940 differentially expressed genes (DEGs) were found to be positively correlated with the granulation level. Gene Ontology (GO) enrichment indicated that the selected DEGs were mainly involved in the cell wall organization and biogenesis, cell wall macromolecule metabolic process, carbohydrate metabolic process, and polysaccharide metabolic process. Among these selected genes, those encoding β-1,4-xylosyltransferase IRX9, cellulose synthase, xyloglucan: xyloglucosyl transferase, xyloglucan galactosyltransferase MUR3, α-1,4-galacturonosyltransferase, expansin, polygalacturonase, pectinesterase, β-glucosidase, β-galactosidase, endo-1,3(4)-β-glucanase, endoglucanase and pectate lyase that required for the biosynthesis or structural modification of cell wall were identified. In addition, NAC, MYB, bHLH, and MADS were the top abundant transcription factors (TFs) families positively correlated with the granulation level, while the LOB was the top abundant TFs family negatively correlated with the granulation level.

Integration of eQTL Analysis and GWAS Highlights Regulation Networks in Cotton under Stress Condition.

The genus Gossypium is one of the most economically important crops in the world. Here, we used RNA-seq to quantify gene expression in a collection of G. arboreum seedlings and performed eGWAS on 28,382 expressed genes. We identified a total of 30,089 eQTLs in 10,485 genes, of which >90% were trans-regulate target genes. Using luciferase assays, we confirmed that different cis-eQTL haplotypes could affect promoter activity. We found ~6600 genes associated with ~1300 eQTL hotspots. Moreover, hotspot 309 regulates the expression of 325 genes with roles in stem length, fresh weight, seed germination rate, and genes related to cell wall biosynthesis and salt stress. Transcriptome-wide association study (TWAS) identified 19 candidate genes associated with the cotton growth and salt stress response. The variation in gene expression across the population played an essential role in population differentiation. Only a small number of the differentially expressed genes between South China, the Yangtze River region, and the Yellow River region sites were located in different chromosomal regions. The eQTLs found across the duplicated gene pairs showed conservative cis- or trans- regulation and that the expression levels of gene pairs were correlated. This study provides new insights into the evolution of gene expression regulation in cotton, and identifies eQTLs in stress-related genes for use in breeding improved cotton varieties.

Genetic Determinants of Biomass in C4 Crops: Molecular and Agronomic Approaches to Increase Biomass for Biofuels.

Bio-based fuels have become popular being efficient, cost-effective, and eco-friendly alternatives to fossil fuels. Among plant sources exploited as feedstocks, C4 grasses, such as sugarcane, maize, sorghum, and miscanthus, are highly resourceful in converting solar energy into chemical energy. For a sustainable and reliable supply of feedstocks for biofuels, we expect dedicated bioenergy crops to produce high biomass using minimum input resources. In recent years, molecular and genetic advancements identified various factors regulating growth, biomass accumulation, and assimilate partitioning. Here, we reviewed important genes involved in cell cycle regulation, hormone dynamics, and cell wall biosynthesis. A number of important transcription factors and miRNAs aid in activation of important genes responsible for cell wall growth and re-construction. Also, environmental components interacting with genetic controls modulate plant biomass by modifying gene expression in multiple interacting pathways. Finally, we discussed recent progress using hybridization and genome editing techniques to improve biomass yield in C4 grasses. This review summarizes genes and environmental factors contributing biomass yield in C4 biofuel crops which can help to discover and design bioenergy crops adapting to changing climate conditions.

Integrated sRNA-seq and RNA-seq Analyses Reveal a microRNA Regulation Network Involved in Cold Response in Pisum sativum L.

(1) Background: Cold stress affects growth and development in plants and is a major environmental factor that decreases productivity. Over the past two decades, the advent of next generation sequencing (NGS) technologies has opened new opportunities to understand the molecular bases of stress resistance by enabling the detection of weakly expressed transcripts and the identification of regulatory RNAs of gene expression, including microRNAs (miRNAs). (2) Methods: In this study, we performed time series sRNA and mRNA sequencing experiments on two pea (Pisum sativum L., Ps) lines, Champagne frost-tolerant and Térèse frost-sensitive, during a low temperature treatment versus a control condition. (3) Results: An integrative analysis led to the identification of 136 miRNAs and a regulation network composed of 39 miRNA/mRNA target pairs with discordant expression patterns. (4) Conclusions: Our findings indicate that the cold response in pea involves 11 miRNA families as well as their target genes related to antioxidative and multi-stress defense mechanisms and cell wall biosynthesis.

NADPH Oxidases Play a Role in Pathogenicity via the Regulation of F-Actin Organization in Colletotrichum gloeosporioides.

Multiunit-flavoenzyme NADPH oxidases (NOXs) play multiple roles in living cells via regulating signaling pathways. In several phytopathogenic fungi, NOXs are required for the polarized growth of hyphal tips and pathogenicity to host plants, but the possible mechanisms are still elusive. In our previous study, CgNOXA, CgNOXB, and CgNOXR were identified as components of the NOX complex in Colletotrichum gloeosporioides. The growth and the inoculation assays revealed that CgNOXA/B and CgNOXR regulate vegetative growth and are required for the full pathogenicity of C. gloeosporioides to Hevea leaves. We further demonstrated that the vital roles of CgNOXB and CgNOXR in appressorium formation and the development of invasion hyphae account for their functions in pathogenicity. Moreover, CgNOXB and CgNOXR regulate the production and distribution of ROS in hyphal tips and appressoria, control the specialized remodeling of F-actin in hyphal tips and appressoria, and are involved in fungal cell wall biosynthesis. Taken together, our findings highlight the role of NOXs in fungal pathogenicity through the organization of the actin cytoskeleton.

Taxonomy, comparative genomics and evolutionary insights of Penicillium ucsense: a novel species in series Oxalica.

The genomes of two Penicillium strains were sequenced and studied in this study: strain 2HH was isolated from the digestive tract of Anobium punctatum beetle larva in 1979 and the cellulase hypersecretory strain S1M29, derived from strain 2HH by a long-term mutagenesis process. With these data, the strains were reclassified and insight is obtained on molecular features related to cellulase hyperproduction and the albino phenotype of the mutant. Both strains were previously identified as Penicillium echinulatum and this investigation indicated that these should be reclassified. Phylogenetic and phenotype data showed that these strains represent a new Penicillium species in series Oxalica, for which the name Penicillium ucsense is proposed here. Six additional strains (SFC101850, SFCP10873, SFCP10886, SFCP10931, SFCP10932 and SFCP10933) collected from the marine environment in the Republic of Korea were also classified as this species, indicating a worldwide distribution of this new taxon. Compared to the closely related strain Penicillium oxalicum 114-2, the composition of cell wall-associated proteins of P. ucsense 2HH shows five fewer chitinases, considerable differences in the number of proteins related to β-D-glucan metabolism. The genomic comparison of 2HH and S1M29 highlighted single amino-acid substitutions in two major proteins (BGL2 and FlbA) that can be associated with the hyperproduction of cellulases. The study of melanin pathways shows that the S1M29 albino phenotype resulted from a single amino-acid substitution in the enzyme ALB1, a precursor of the 1,8-dihydroxynaphthalene (DHN)-melanin biosynthesis. Our study provides important knowledge towards understanding species distribution, molecular mechanisms, melanin production and cell wall biosynthesis of this new Penicillium species.

Multi-Target Antibacterial Mechanism of Moringin From Moringa oleifera Seeds Against Listeria monocytogenes.

Moringin [4-(α-L-rhamnosyloxy) benzyl isothiocyanate] is an isothiocyanate from Moringa oleifera seeds. It is the bioactivated form of the glucosinolate precursor glucomoringin with various health benefits. However, few studies have examined the antibacterial activity of moringin. This study aimed to investigate the antimicrobial activity and mechanism of moringin against Listeria monocytogenes. The minimum inhibitory concentration (MIC), and growth curves were used to evaluate the bacteriostatic effect of moringin against L. monocytogenes. Transcriptome analysis by RNA sequencing was performed to elucidate the underlying mechanism of moringin against L. monocytogenes. The transcriptome results were validated. The results showed that moringin inhibited the growth of L. monocytogenes with a MIC of 400 μM. RNA sequencing results showed that the differences in the expression of genes related to the cell wall and membrane biosynthesis, phosphotransferase system (PTS), oxidative stress, energy metabolism, and DNA binding were significantly affected. As with the transcriptome results, the results of the mechanism verification found that moringin damaged the integrity of the cell wall and cell membrane, stimulated oxidative stress, interfered with energy metabolism and DNA replication, and finally led to the death of L. monocytogenes. The present study provides evidence that moringin exhibits strong antimicrobial activity against L. monocytogenes and insight into its potential mechanism.

Olea europaea mediated bioengineered biocompatible gold nanoparticles for antimicrobial, cytotoxic applications, and molecular docking study

The objective of this research work is to demonstrate the ecologically friendly fabrication of gold nanoparticles (OL-Au NAPs) using the biomolecules of Olea europaea leaf extract. Several spectroscopic approaches were utilized to analyze green fabricated OL-Au NAPs efficiently. OL-Au NAPs were investigated against two different bacteriological strains for antibacterial and biofilm inhibition efficacy. The MTT technique was used to determine the cytotoxic activity against MCF-7 cancerous cells, which was expressed as a percentage of viable cells. The biocompatibility of the synthesized NAPs was evaluated further by incubating them for 24 h with hMSC and 293T cell lines. The results indicated that synthesized OL-Au NAPs effectively suppressed proliferation and biofilm formation in all tested bacteria. Their antibacterial activity was statistically equivalent to that of standard antibiotics (p > 0.05). In silico molecular docking studies confirmed that OL-Au NAPs can also bind and inhibit important S. aureus proteins involved in the cell wall and fatty acid biosynthesis pathways. Moreover, they outperformed plant leaf extract and CH-Au NAPs in terms of cytotoxic effects on MCF-7 cancerous cells. Green fabricated OL-Au NAPs seemed more biocompatible with 293T and hMSC cells than CH-Au NAPs. The promising biological properties of the OL-Au NAPs may be a result of the NAPs' properties interacting with the adsorbed bioactive molecules from plant leaf extract. As a consequence of this study, synthesized OL-Au NAPs may be a potential choice for their numerous pharmacological and nutritional properties. This discovery will also open the road for the creation of nontoxic nanomaterials with extra biologic properties obtained from plants.

Bioinformatic prospecting and synthesis of a bifunctional lipopeptide antibiotic that evades resistance.

Emerging resistance to currently used antibiotics is a global public health crisis. Because most of the biosynthetic capacity within the bacterial kingdom has remained silent in previous antibiotic discovery efforts, uncharacterized biosynthetic gene clusters found in bacterial genome-sequencing studies remain an appealing source of antibiotics with distinctive modes of action. Here, we report the discovery of a naturally inspired lipopeptide antibiotic called cilagicin, which we chemically synthesized on the basis of a detailed bioinformatic analysis of the cil biosynthetic gene cluster. Cilagicin's ability to sequester two distinct, indispensable undecaprenyl phosphates used in cell wall biosynthesis, together with the absence of detectable resistance in laboratory tests and among multidrug-resistant clinical isolates, makes it an appealing candidate for combating antibiotic-resistant pathogens.

Revealing Genetic Differences in Fiber Elongation between the Offspring of Sea Island Cotton and Upland Cotton Backcross Populations Based on Transcriptome and Weighted Gene Coexpression Networks.

Fiber length is an important indicator of cotton fiber quality, and the time and rate of cotton fiber cell elongation are key factors in determining the fiber length of mature cotton. To gain insight into the differences in fiber elongation mechanisms in the offspring of backcross populations of Sea Island cotton Xinhai 16 and land cotton Line 9, we selected two groups with significant differences in fiber length (long-fiber group L and short-fiber group S) at different fiber development stages 0, 5, 10 and 15 days post-anthesis (DPA) for transcriptome comparison. A total of 171.74 Gb of clean data was obtained by RNA-seq, and eight genes were randomly selected for qPCR validation. Data analysis identified 6055 differentially expressed genes (DEGs) between two groups of fibers, L and S, in four developmental periods, and gene ontology (GO) term analysis revealed that these DEGs were associated mainly with microtubule driving, reactive oxygen species, plant cell wall biosynthesis, and glycosyl compound hydrolase activity. Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis indicated that plant hormone signaling, mitogen-activated protein kinase (MAPK) signaling, and starch and sucrose metabolism pathways were associated with fiber elongation. Subsequently, a sustained upregulation expression pattern, profile 19, was identified and analyzed using short time-series expression miner (STEM). An analysis of the weighted gene coexpression network module uncovered 21 genes closely related to fiber development, mainly involved in functions such as cell wall relaxation, microtubule formation, and cytoskeletal structure of the cell wall. This study helps to enhance the understanding of the Sea Island–Upland backcross population and identifies key genes for cotton fiber development, and these findings will provide a basis for future research on the molecular mechanisms of fiber length formation in cotton populations.

RNA-seq analysis and transcriptome assembly of Salicornia neei reveals a powerful system for ammonium detoxification

BackgroundSalicornia neei is a halophyte plant that has been proposed for use in the phytoremediation of the saline wastewater generated by land-based aquaculture. To identify the molecular mechanisms related to ammonium response, we analyzed the transcriptome of S. neei in response to growth in saline water containing 3 mM ammonium. ResultsThe RNA sequencing generated a total of 14,680,108 paired-end reads from the control and stressed conditions. De novo assembly using the CLC Genomic Workbench produced 86,020 transcripts and a reference transcriptome with an N50 of 683 base pair.A total of 45,327 genes were annotated, representing 51.2% of the contig predicted from de novo assembly. As regards differentially expressed genes, a total of 9,140 genes were differentially expressed in response to ammonium in saline water; of these, 7,396 could be annotated against functional databases. The upregulated genes were mainly involved in cell wall biosynthesis, transmembrane transport and antiporter activities, including biological Kyoto Encyclopedia of Genes and Genomes, pathways linked to the biosynthesis of secondary metabolites, plant hormone signal transduction, autophagy, and nitrogen metabolism. In addition, a set of 72 genes was directly involved in ammonium metabolism, including glutamine synthetase 1, glutamate synthase 1, and ferredoxin-dependent glutamate synthase chloroplastic. ConclusionsOur results support the hypothesis that an ammonium detoxification system mediated by glutamine and glutamate synthase was activated in S. neei when exposed to ammonium and saline water. The present transcriptome profiling method could be useful when investigating the response of halophyte plants to saline wastewater from land-based aquaculture.This manuscript includes an interactive 360 degree video, supplementary to the materials and methods section. To view the video correctly, it is necessary to scroll through the screen to navigate across the laboratory where you will find 6 interactive points. For an immersive experience a head-mounted display can be used. Please, visit this URL:http://ejbiotechnology.info/public/360view/2022/VTPGALLARDO_1v3/index.htm.How to cite: Díaz-Silva M, Maldonado J, Veloso P, et al. RNA-seq analysis and transcriptome assembly of Salicornia neei reveals a powerful system for ammonium detoxification. Electron J Biotechnol 2022;58. https://doi.org/10.1016/j.ejbt.2022.05.003

Microtubule‐associated IQD9 orchestrates cellulose patterning in seed mucilage

Arabidopsis seeds release large capsules of mucilaginous polysaccharides, which are shaped by an intricate network of cellulosic microfibrils. Cellulose synthase complexes are guided by the microtubule cytoskeleton, but it is unclear which proteins mediate this process in the seed coat epidermis. Using reverse genetics, we identified IQ67 DOMAIN 9 (IQD9) and KINESIN LIGHT CHAIN-RELATED 1 (KLCR1) as two highly expressed genes during seed development and comprehensively characterized their roles in cell wall polysaccharide biosynthesis. Mutations in IQD9 as well as in KLCR1 lead to compact mucilage capsules with aberrant cellulose distribution, which can be rescued by transgene complementation. IQD9 physically interacts with KLCR1 and localizes to cortical microtubules (MTs) to maintain their organization in seed coat epidermal (SCE) cells. IQD9 as well as a previously identified TONNEAU1 (TON1) RECRUITING MOTIF 4 (TRM4) protein act to maintain cellulose synthase velocity. Our results demonstrate that IQD9, KLCR1 and TRM4 are MT-associated proteins that are required for seed mucilage architecture. This study provides the first direct evidence that members of the IQD, KLCR and TRM families have overlapping roles in cell wall biosynthesis. Therefore, SCE cells provide an attractive system to further decipher the complex genetic regulation of polarized cellulose deposition.