Effect of Insecticides Imidacloprid and Alpha-Cypermethrin on the Development of Pea ( L.) Nodules.

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 ( L.

Dynamics of Hydrogen Peroxide Accumulation During Tip Growth of Infection Thread in Nodules and Cell Differentiation in Pea ( L.) Symbiotic Nodules.

Hydrogen peroxide (HO) in plants is produced in relatively large amounts and plays a universal role in plant defense and physiological responses, including the regulation of growth and development. In the -legume symbiosis, hydrogen peroxide plays an important signaling role throughout the development of this interaction. In the functioning nodule, HO has been shown to be involved in bacterial differentiation into the symbiotic form and in nodule senescence.

Whole-genome sequence of six strains.

is regarded as a promising candidate for biofertilization of legume plants worldwide through its high efficiency in symbiosis. In this paper, we report high-quality sequences of six strains with total genome completeness from 93.5% to 97.

Effects of Elevated Temperature on Nodule Development: I-Detailed Characteristic of Unusual Apical Senescence.

Despite global warming, the influence of heat on symbiotic nodules is scarcely studied. In this study, the effects of heat stress on the functioning of nodules formed by bv. strain 3841 on pea () line SGE were analyzed.

Comparison of the Formation of Plant-Microbial Interface in L. and Gaertn. Nitrogen-Fixing Nodules.

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 and 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.

RopB protein of bv. adopts amyloid state during symbiotic interactions with pea ( L.).

Amyloids represent protein aggregates with highly ordered fibrillar structure associated with the development of various disorders in humans and animals and involved in implementation of different vital functions in all three domains of life. In prokaryotes, amyloids perform a wide repertoire of functions mostly attributed to their interactions with other organisms including interspecies interactions within bacterial communities and host-pathogen interactions. Recently, we demonstrated that free-living cells of , a nitrogen-fixing symbiont of legumes, produce RopA and RopB which form amyloid fibrils at cell surface during the stationary growth phase thus connecting amyloid formation and host-symbiont interactions.

A variable gene family encoding nodule-specific cysteine-rich peptides in pea ( L.).

Various legume plants form root nodules in which symbiotic bacteria (rhizobia) fix atmospheric nitrogen after differentiation into a symbiotic form named bacteroids. In some legume species, bacteroid differentiation is promoted by defensin-like nodule-specific cysteine-rich (NCR) peptides. NCR peptides have best been studied in the model legume Gaertn.

Tubulin Cytoskeleton Organization in Cells of Determinate Nodules.

Plant cell differentiation is based on rearrangements of the tubulin cytoskeleton; this is also true for symbiotic nodules. Nevertheless, although for indeterminate nodules (with a long-lasting meristem) the organization of microtubules during nodule development has been studied for various species, for determinate ones (with limited meristem activity) such studies are rare. Here, we investigated bacteroid morphology and dynamics of the tubulin cytoskeleton in determinate nodules of four legume species: , , , and .

The Regulation of Pea ( L.) Symbiotic Nodule Infection and Defense Responses by Glutathione, Homoglutathione, and Their Ratio.

In this study, the roles of glutathione (GSH), homoglutathione (hGSH), and their ratio in symbiotic nodule development and functioning, as well as in defense responses accompanying ineffective nodulation in pea () were investigated. The expression of genes involved in (h)GSH biosynthesis, thiol content, and localization of the reduced form of GSH were analyzed in nodules of wild-type pea plants and mutants (weak allele, "locked" infection threads, occasional bacterial release, and defense reactions) and (strong allele, "locked" infection threads, defense reactions), and (abnormal bacteroids, oxidative stress, early senescence, and defense reactions). The effects of (h)GSH depletion and GSH treatment on nodule number and development were also examined.

Symbiotic Regulatory Genes Controlling Nodule Development in L.

Analyses of natural variation and the use of mutagenesis and molecular-biological approaches have revealed 50 symbiotic regulatory genes in pea ( L.). Studies of genomic synteny using model legumes, such as Gaertn.

The Fungicide Tetramethylthiuram Disulfide Negatively Affects Plant Cell Walls, Infection Thread Walls, and Symbiosomes in Pea ( L.) Symbiotic Nodules.

In Russia, tetramethylthiuram disulfide (TMTD) is a fungicide widely used in the cultivation of legumes, including the pea (). Application of TMTD can negatively affect nodulation; nevertheless, its effect on the histological and ultrastructural organization of nodules has not previously been investigated. In this study, the effect of TMTD at three concentrations (0.

Mutational analysis indicates that abnormalities in rhizobial infection and subsequent plant cell and bacteroid differentiation in pea (Pisum sativum) nodules coincide with abnormal cytokinin responses and localization.

Background And Aims: Recent findings indicate that Nod factor signalling is tightly interconnected with phytohormonal regulation that affects the development of nodules. Since the mechanisms of this interaction are still far from understood, here the distribution of cytokinin and auxin in pea (Pisum sativum) nodules was investigated. In addition, the effect of certain mutations blocking rhizobial infection and subsequent plant cell and bacteroid differentiation on cytokinin distribution in nodules was analysed.

Efficacy of a Plant-Microbe System: (L.) Cadmium-Tolerant Mutant and Strains, Expressing Pea Metallothionein Genes and , for Cadmium Phytoremediation.

Two transgenic strains of bv. , 3841-PsMT1 and 3841-PsMT2, were obtained. These strains contain the genetic constructions and coding for two pea ( L.

Bacterial release is accompanied by ectopic accumulation of cell wall material around the vacuole in nodules of Pisum sativum sym33-3 allele encoding transcription factor PsCYCLOPS/PsIPD3.

Pisum sativum symbiotic mutant SGEFix-2 carries the sym33-3 allele of the gene Sym33, encoding transcription factor PsCYCLOPS/PsIPD3. Previously, strong host cell defence reactions were identified in nodules of this mutant. In the present study, new manifestations of defence reactions were revealed in 28-day-old white nodules in which bacterial release had occurred.

Gibberellins Inhibit Nodule Senescence and Stimulate Nodule Meristem Bifurcation in Pea ( L.).

The development of nitrogen-fixing nodules formed during -legume symbiosis is strongly controlled by phytohormones. In this study, we investigated the effect of gibberellins (GAs) on senescence of pea () symbiotic nodules. Pea wild-type line SGE, as well as corresponding mutant lines SGEFix-1 (), SGEFix-2 (), SGEFix-3 (), and SGEFix-7 (), blocked at different stages of nodule development, were used in the study.

Comparative analysis of remodelling of the plant-microbe interface in Pisum sativum and Medicago truncatula symbiotic nodules.

Infection of host cells by nitrogen-fixing soil bacteria, known as rhizobia, involves the progressive remodelling of the plant-microbe interface. This process was examined by using monoclonal antibodies to study the subcellular localisation of pectins and arabinogalactan proteins (AGPs) in wild-type and ineffective nodules of Pisum sativum and Medicago truncatula. The highly methylesterified homogalacturonan (HG), detected by monoclonal antibody JIM7, showed a uniform localisation in the cell wall, regardless of the cell type in nodules of P.

Early nodule senescence is activated in symbiotic mutants of pea (Pisum sativum L.) forming ineffective nodules blocked at different nodule developmental stages.

Plant symbiotic mutants are useful tool to uncover the molecular-genetic mechanisms of nodule senescence. The pea (Pisum sativum L.) mutants SGEFix-1 (sym40), SGEFix-3 (sym26), and SGEFix-7 (sym27) display an early nodule senescence phenotype, whereas the mutant SGEFix-2 (sym33) does not show premature degradation of symbiotic structures, but its nodules show an enhanced immune response.

Cell differentiation in nitrogen-fixing nodules hosting symbiosomes.

The nitrogen-fixing nodule is a unique ecological niche for rhizobia, where microaerobic conditions support functioning of the main enzyme of nitrogen fixation, nitrogenase, which is highly sensitive to oxygen. To accommodate bacteria in a symbiotic nodule, the specialised infected cells increase in size owing to endoreduplication and are able to shelter thousands of bacteria. Bacteria are isolated from the cytoplasm of the plant cell by a membrane-bound organelle-like structure termed the symbiosome.

Induction of host defences by Rhizobium during ineffective nodulation of pea (Pisum sativum L.) carrying symbiotically defective mutations sym40 (PsEFD), sym33 (PsIPD3/PsCYCLOPS) and sym42.

Rhizobia are able to establish a beneficial interaction with legumes by forming a new organ, called the symbiotic root nodule, which is a unique ecological niche for rhizobial nitrogen fixation. Rhizobial infection has many similarities with pathogenic infection and induction of defence responses accompanies both interactions, but defence responses are induced to a lesser extent during rhizobial infection. However, strong defence responses may result from incompatible interactions between legumes and rhizobia due to a mutation in either macro- or microsymbiont.