Search Results (41)

The plant parasitic root-knot nematodes of the species Meloidogyne incognita infect many cultivated plants, one of which is the tomato (Solanum lycopersicum). To be fed, M. incognita selects unique feeding sites inside the root and induces the formation of large galls (knots) encompassing the so-called giant cells (GCs). In the present study, a comparative analysis of the GCs/root cell and cell wall components between M. incognita-infected and uninfected tomato plants and plants pre-treated with the plant biostimulant and nematicide acetic acid (AA) was carried out. Pectin, hemicellulose and extensin epitopes were detected in tomato root sections. M. incognita-induced GCs in tomato roots had cell walls with arabinans, unesterified/methylesterified homogalacturonans and xyloglucans, but were devoid of mannans and extensins. Interestingly, the above epitope distribution also differed in root sections made near the formed root knot, proximal to the root cap. Moreover, it seemed that AA was able to induce the deposition of extensins in AA-treated, M. incognita-uninfected roots and hamper the GC development in AA-treated, M. incognita-infected roots. According to the above the AA, stimulates natural defense mechanisms in tomato, thus protecting it from nematode infestation. Full article

The proline-rich extensin-like receptor kinase (PERK) gene family is crucial to various molecular and cellular processes in plants. We identified 50 PERK genes in Brassica napus to explore their evolutionary dynamics, structural diversity, and functional roles. These genes were grouped into four classes and unevenly distributed across 18 chromosomes. Phylogenetic studies and Ka/Ks ratios revealed purifying selection during the evolution process. They exhibited significant diversification in gene length, molecular weight, and isoelectric points, suggesting specialized function. Gene structure and motif analyses revealed variations among the BnPERK family members, with conserved tyrosine kinase domains suggesting functional importance. Cis-element analysis predicted the involvement in hormone signaling and stress responses. Expression profiling showed diverse patterns across tissues and hormone treatments, highlighting potential roles in growth regulation and hormone signaling. Protein–protein interaction networks suggested BnPERK proteins interact with a wide array of proteins, implicating them in multiple biological processes. The transcriptional downregulation of four BnPERK genes upon Plasmodiophora brassicae infection implied a role in clubroot disease response. Furthermore, the Arabidopsis perk9 mutant displayed relieved disease severity and enhanced basal immune response, suggesting the negative role of PERK9 in plant immunity. The study highlighted the potential role of BnPERKs in crop improvement strategies against clubroot disease. Full article

Insecticides are used commonly in agricultural production to defend plants, including legumes, from insect pests. It is a known fact that insecticides can have a harmful effect on the legume–rhizobial symbiosis. In this study, the effects of systemic seed treatment insecticide Imidor Pro (imidacloprid) and foliar insecticide Faskord (alpha-cypermethrin) on the structural organization of pea (Pisum sativum L.) nodules and their transcriptomic activity were investigated. The plants were treated as recommended by the manufacturer (10 mg/mL for Imidor Pro and 50 µg/mL for Faskord) and twofold concentrations were used for both insecticides. Insecticides had no visible effect on the growth of pea plants. The nodules also showed no visible changes, except for the variant treated with twofold concentration of Imidor Pro. However, the dry weight of shoots and roots differed significantly in insecticide-treated plants compared to untreated plants in almost all treatments. The number of nodules decreased in variants with Imidor Pro treatment. At the ultrastructural level, both insecticides caused cell wall deformation, poly-β-hydroxybutyrate accumulation in bacteroids, expansion of the peribacteroid space in symbiosomes, and inclusions in vacuoles. Treatment with Faskord caused chromatin condensation in nucleus. Imidor Pro treatment caused hypertrophy of infection droplets by increasing the amount of matrix, as confirmed by immunofluorescence analysis of extensins. Transcriptome analysis revealed upregulation of expression of a number of extensin-like protein-coding genes in nodules after the Imidor Pro treatment. Overall, both insecticides caused some minor changes in the legume–rhizobial system when used at recommended doses, but Faskord, an enteric contact insecticide, has fewer negative effects on symbiotic nodules and legume plants; of these two insecticides, it is preferred in pea agricultural production. Full article

Liparis loeselii (L.) Rich, an endangered member of the Orchidaceae family, is found in alkaline fens. With the declining populations of L. loeselii, there is a pressing need to reintroduce this species in Central Europe. As in vitro germination is a crucial tool for obtaining plants for introduction into the environment, we looked at the morphological changes occurring during the early stages of L. loeselii development in vitro. As the early stages of orchid development, especially the protocorm stage, are thought to be responsible for SAM formation and the initiation of symbiotic association, we focused on cell wall elements whose epitopes have been found in similar processes in other species: the extensin and pectin rhamnogalacturonan I (RG-I) side chain epitopes. We addressed the following questions: Does the cell wall of L. loeselii change its composition during the early stages of development, as noted in other species? Are there noticeable similarities in the cell wall to organs of different species whose function is to contact microorganisms? Are there regularities that allow the recognition of individual structures on this basis? Immunolocalization revealed changes in the distribution of certain extensins (JIM11 and JIM20) and RG-I (LM5 and LM6) side chain epitopes. Extensins, a type of cell wall protein, were observed during the initial stages of the formation of PLB and the shoot apical meristem of protocorms and PLBs. RG-I, on the other hand, was found to play a significant role in the development of the protocorm and PLB. In pseudobulbs, which appeared on the protocorms, extensins occurred in their storage part. However, RG-I side chains (1→4)-β-galactans (LM5), and (1→5)-α-L-arabinans (LM6) were not found in pseudobulbs. We revealed that a common feature of protocorms and PLBs was an increased amount of extensins, which were detected with the JIM11 antibody, and pectins, which were detected with the LM5 antibody, that were present together, which may prove helpful in determining the identity of the induced structures and distinguishing them from pseudobulbs. Thus, our study unveiled the role of extensins and RG-I during the growth of protocorms and PLBs. We suggest that PLBs may mimic the wall remodelling that occurs in protocorms, which indicates that using cell wall components is an invitation to be colonised by a fungal partner. However, this needs to be tested in future research. The findings of this research can help interpret future studies on the propagation, acclimatisation, and introduction of L. loeselii into the natural environment. Full article

Large and distinct families of receptor-like kinases (RLKs) play elemental roles in many fundamental processes of plants. The proline-rich extensin-like receptor kinase (PERK) family is one of the most pivotal classes of RLKs. To date, there have been no comprehensive or published studies conducted on the PERK gene family in Glycine max. This research aimed to characterize the role of the PERK gene family in cultivated soybean using a systematic array of bioinformatic and experimental approaches. We identified 16 PERK members in G. max through local BLASTp, using PERK members from Arabidopsis thaliana as a query. Tissue expression of genes, predicted via tissue specific expression analysis from the soybean database “SoyBase”, revealed that these PERK genes exhibit differentiated expression patterns in various plant organs. The gene structure was predicted via Gene Structure Display Server (GSDS). Phylogeny was demonstrated through an evolutionary tree employing the neighbor-joining method. Subcellular localization of proteins was identified via “Softberry” and cis-acting elements were identified through PlantCARE. The KASP (Kompetitive Allele Specific PCR (KASP)) marker was developed for the GmPERK-1-C and GmPERK-1-T allele, targeting position 167 nt in the CDS region. Genotyping results indicated that GmPERK-1 exhibits promising potential for utilization in molecular breeding programs for soybean to increase crop yield. Collectively, our findings indicate that G. max accessions harboring the GmPERK-1-C allele exhibit significantly higher thousand grain weight compared to accessions carrying the GmPERK-1-T allele. This research enhances the understanding of the molecular roles of PERK genes in G. max, providing valuable insights for the utilization of favorable genetic variations in soybean molecular breeding programs. Full article

Leucine-rich repeat extensin (LRX) is involved in the regulation of crucial cellular processes, such as cell wall growth and development, as well as signaling. However, the presence of the LRX gene family in Brassica rapa (B. rapa) has not been previously reported. This study identified 17 BrLRXs within the Brassica rapa genome by bioinformatic analysis, and these genes were distributed on seven chromosomes. Phylogenetic and covariance analyses indicate that BrLRXs can be categorized into two distinct branches: the trophic branch and the reproductive branch, with a close relationship observed between BrLRXs and AtLRXs. According to cis-acting element analysis, this gene family is rich in hormone-responsive and stress-responsive elements such as drought-inducibility, abscisic acid, methyl jasmonate, and gibberellic acid responsive elements, suggesting a potential role in abiotic stress response. Transcriptomic, proteomic, and RT-qPCR analyses demonstrated significant up-regulation of BrLRX2 and BrLRX6 under salt stress, while BrLRX3, BrLRX6, and BrLRX8 were significantly down-regulated under osmotic stress. Our analysis of the protein tertiary structure predicts a strong association between LRX proteins and RALF. Protein–protein interaction prediction revealed that LRX interacts with the RALF protein and the receptor FER, which have been previously reported to jointly regulate plant stress responses. We propose that BrLRX6 and BrLRX8 are implicated in osmotic stress, while BrLRX2 and BrLRX6 are involved in the modulation of salt stress. Full article

Svx proteins are virulence factors secreted by phytopathogenic bacteria of the Pectobacterium genus into the host plant cell wall. Svx-encoding genes are present in almost all species of the soft rot Pectobacteriaceae (Pectobacterium and Dickeya genera). The Svx of P. atrosepticum (Pba) has been shown to be a gluzincin metallopeptidase that presumably targets plant extensins, proteins that contribute to plant cell wall rigidity and participate in cell signaling. However, the particular “output” of the Pba Svx action in terms of plant-pathogen interactions and plant immune responses remained unknown. The Svx proteins are largely unexplored in Dickeya species, even though some of them have genes encoding two Svx homologs. Therefore, our study aims to compare the structural and catalytic properties of the Svx proteins of Pba and D. solani (Dso) and to test the phytoimmune properties of these proteins. Two assayed Dso Svx proteins, similar to Pba Svx, were gluzincin metallopeptidases with conservative tertiary structures. The two domains of the Svx proteins form electronegative clefts where the active centers of the peptidase domains are located. All three assayed Svx proteins possessed phytoimmunosuppressory properties and induced ethylene-mediated plant susceptible responses that play a decisive role in Pba-caused disease. Full article

To explore the key genes involved in cell wall synthesis and understand the molecular mechanism of cell wall assembly in the model alga-Chlamydomonas reinhardtii, transcriptome sequencing was used to discover the differentially expressed genes in the cell wall defective strain. In the glucose metabolism, lipid metabolism, and amino acid metabolism pathways, the gene expressions involved in the synthesis of cell wall functional components were analyzed. The results showed that in the cell wall defective strain, arabinosyltransferase gene (XEG113, RRA) related to synthesis of plant extensin and some cell wall structural protein genes (hyp, PHC19, PHC15, PHC4, PHC3) were up-regulated, 1,3-β-glucan synthase gene (Gls2) and endoglucanase gene (EG2) about synthesis and degradation of glycoskeleton were both mainly up-regulated. Then, ethambutol dihydrochloride, an arabinosyltransferase inhibitor, was found to affect the permeability of the cell wall of the normal strain, while the cell wall deficient strain was not affected. To further research the function of arabinosyltransferase, the RRA gene was inactivated by knockout in the normal cell wall algal strain. Through a combination of microscope observation and physiological index detection, it was found that the cell wall of the mutant strains showed reduced structure levels, suggesting that the structure and function of the cell wall glycoprotein were weakened. Therefore, arabinosyltransferase may affect the glycosylation modification of cell wall glycoprotein, further affecting the structure assembly of cell wall glycoprotein. Full article

One of the most destructive diseases, Gibberella stalk rot (GSR), caused by Fusarium graminearum, reduces maize yields significantly. An induced resistance response is a potent and cost-effective plant defense against pathogen attack. The functional counterpart of JAs, coronatine (COR), has attracted a lot of interest recently due to its ability to control plant growth and stimulate secondary metabolism. Although several studies have focused on COR as a plant immune elicitor to improve plant resistance to pathogens, the effectiveness and underlying mechanisms of the suppressive ability against COR to F. graminearum in maize have been limited. We investigated the potential physiological and molecular mechanisms of COR in modulating maize resistance to F. graminearum. COR treatment strongly enhanced disease resistance and promoted stomatal closure with H₂O₂ accumulation, and 10 μg/mL was confirmed as the best concentration. COR treatment increased defense-related enzyme activity and decreased the malondialdehyde content with enhanced antioxidant enzyme activity. To identify candidate resistance genes and gain insight into the molecular mechanism of GSR resistance associated with COR, we integrated transcriptomic and metabolomic data to systemically explore the defense mechanisms of COR, and multiple hub genes were pinpointed using weighted gene correlation network analysis (WGCNA). We discovered 6 significant modules containing 10 candidate genes: WRKY transcription factor (LOC100279570), calcium-binding protein (LOC100382070), NBR1-like protein (LOC100275089), amino acid permease (LOC100382244), glutathione S-transferase (LOC541830), HXXXD-type acyl-transferase (LOC100191608), prolin-rich extensin-like receptor protein kinase (LOC100501564), AP2-like ethylene-responsive transcription factor (LOC100384380), basic leucine zipper (LOC100275351), and glycosyltransferase (LOC606486), which are highly correlated with the jasmonic acid–ethylene signaling pathway and antioxidants. In addition, a core set of metabolites, including alpha-linolenic acid metabolism and flavonoids biosynthesis linked to the hub genes, were identified. Taken together, our research revealed differentially expressed key genes and metabolites, as well as co-expression networks, associated with COR treatment of maize stems after F. graminearum infection. In addition, COR-treated maize had higher JA (JA-Ile and Me-JA) levels. We postulated that COR plays a positive role in maize resistance to F. graminearum by regulating antioxidant levels and the JA signaling pathway, and the flavonoid biosynthesis pathway is also involved in the resistance response against GSR. Full article

Different components of the symbiotic interface play an important role in providing positional information during rhizobial infection and nodule development: successive changes in cell morphology correspond to subsequent changes in the molecular architecture of the apoplast and the associated surface structures. The localisation and distribution of pectins, xyloglucans, and cell wall proteins in symbiotic nodules of Pisum sativum and Medicago truncatula were studied using immunofluorescence and immunogold analysis in wild-type and ineffective mutant nodules. As a result, the ontogenetic changes in the symbiotic interface in the nodules of both species were described. Some differences in the patterns of distribution of cell wall polysaccharides and proteins between wild-type and mutant nodules can be explained by the activation of defence reaction or premature senescence in mutants. The absence of fucosylated xyloglucan in the cell walls in the P. sativum nodules, as well as its predominant accumulation in the cell walls of uninfected cells in the M. truncatula nodules, and the presence of the rhamnogalacturonan I (unbranched) backbone in meristematic cells in P. sativum can be attributed to the most striking species-specific features of the symbiotic interface. Full article

Although the influence of nanoparticles (NPs) on developmental processes is better understood, little is known about their impact on somatic embryogenesis (SE). This process involves changes in the direction of cell differentiation. Thus, studying the effect of NPs on SE is essential to reveal their impact on cell fate. This study aimed to examine the influence of gold nanoparticles (Au NPs) with different surface charges on the SE of 35S:BBM Arabidopsis thaliana, with particular emphasis on the spatiotemporal localization of pectic arabinogalactan proteins (AGPs) and extensin epitopes in cells changing the direction of their differentiation. The results show that under the influence of nanoparticles, the explant cells of 35S:BBM Arabidopsis thaliana seedling origin did not enter the path of SE. Bulges and the formation of organ-like structures were observed in these explants, in contrast to the control, where somatic embryos developed. Additionally, spatiotemporal changes in the chemical composition of the cell walls during the culture were observed. Under the influence of Au NPs, the following effects were observed: (1) explant cells did not enter the SE pathway, (2) the impacts of Au NPs with different surface charges on the explants were variable, and (3) the compositions of the analyzed pectic AGPs and extensin epitopes were diverse in the cells with different developmental programs: SE (control) and non-SE (treated with Au NPs). Full article

Somatic embryogenesis (SE) is a process that scientists have been trying to understand for many years because, on the one hand, it is a manifestation of the totipotency of plant cells, so it enables the study of the mechanisms regulating this process, and, on the other hand, it is an important method of plant propagation. Using SE in basic research and in practice is invaluable. This article describes the latest, but also historical, information on changes in the chemical composition of the cell wall during the transition of cells from the somatic to embryogenic state, and the importance of symplasmic communication during SE. Among wall chemical components, different pectic, AGP, extensin epitopes, and lipid transfer proteins have been discussed as potential apoplastic markers of explant cells during the acquisition of embryogenic competence. The role of symplasmic communication/isolation during SE has also been discussed, paying particular attention to the formation of symplasmic domains within and between cells that carry out different developmental processes. Information about the number and functionality of plasmodesmata (PD) and callose deposition as the main player in symplasmic isolation has also been presented. Full article

A special feature found in Amaryllidaceae is that some guard cells of the neighboring stomata form a “connection strand” between their dorsal cell walls. In the present work, this strand was studied in terms of both its composition and its effect on the morphology and function of the stomata in Pancratium maritimum L. leaves. The structure of stomata and their connection strand were studied by light and transmission electron microscopy. FM 4–64 and aniline blue staining and application of tannic acid were performed to detect cell membranes, callose, and pectins, respectively. A plasmolysis experiment was also performed. The composition of the connection strand was analyzed by fluorescence microscopy after immunostaining with several cell-wall-related antibodies, while pectinase treatment was applied to confirm the presence of pectins in the connection strand. To examine the effect of this connection on stomatal function, several morphological characteristics (width, length, size, pore aperture, stomatal distance, and cell size of the intermediate pavement cell) were studied. It is suggested that the connecting strand consists of cell wall material laid through the middle of the intermediate pavement cell adjoining the two stomata. These cell wall strands are mainly comprised of pectins, and crystalline cellulose and extensins were also present. Connected stomata do not open like the single stomata do, indicating that the connection strand could also affect stomatal function. This trait is common to other Amaryllidaceae representatives. Full article

Proline-rich extensin-like receptor protein kinases (PERKs) are known for their roles in the developmental processes and stress responses of many plants. We have identified 30 TaPERK genes in the genome of T. aestivum, exploring their evolutionary and syntenic relationship and analyzing their gene and protein structures, various cis-regulatory elements, expression profiling, and interacting miRNAs. The TaPERK genes formed 12 homeologous groups and clustered into four phylogenetic clades. All the proteins exhibited a typical domain organization of PERK and consisted of conserved proline residue repeats and serine-proline and proline-serine repeats. Further, the tyrosine-x-tyrosine (YXY) motif was also found conserved in thirteen TaPERKs. The cis-regulatory elements and expression profiling under tissue developmental stages suggested their role in plant growth processes. Further, the differential expression of certain TaPERK genes under biotic and abiotic stress conditions suggested their involvement in defense responses as well. The interaction of TaPERK genes with different miRNAs further strengthened evidence for their diverse biological roles. In this study, a comprehensive analysis of obtained TaPERK genes was performed, enriching our knowledge of TaPERK genes and providing a foundation for further possible functional analyses in future studies. Full article

The Svx proteins are virulence factors of phytopathogenic bacteria of the Pectobacterium genus. The specific functions of these proteins are unknown. Here we show that most of the phytopathogenic species of Pectobacterium, Dickeya, and Xanthomonas genera have genes encoding Svx proteins, as well as some plant-non-associated species of different bacterial genera. As such, the Svx-like proteins of phytopathogenic species form a distinct clade, pointing to the directed evolution of these proteins to provide effective interactions with plants. To get a better insight into the structure and functions of the Svx proteins, we analyzed the Svx of Pectobacterium atrosepticum (Pba)—an extracellular virulence factor secreted into the host plant cell wall (PCW). Using in silico analyses and by obtaining and analyzing the recombinant Pba Svx and its mutant forms, we showed that this protein was a gluzincin metallopeptidase. The 3D structure model of the Pba Svx was built and benchmarked against the experimental overall secondary structure content. Structure-based substrate specificity analysis using molecular docking revealed that the Pba Svx substrate-binding pocket might accept α-glycosylated proteins represented in the PCW by extensins—proteins that strengthen the PCW. Thus, these results elucidate the way in which the Pba Svx may contribute to the Pba virulence. Full article