Local and systemic targets of the MtCLE35-SUNN pathway in the roots of Medicago truncatula.

CLE (CLAVATA3/ENDOSPERM SURROUNDING REGION-related) peptides are systemic regulators of legume-rhizobium symbiosis that negatively control the number of nitrogen-fixing nodules. CLE peptides are produced in the root in response to rhizobia inoculation and/or nitrate treatment and are transported to the shoot where they are recognized by the CLV1-like (CLAVATA1-like) receptor kinase. As a result, a shoot-derived signaling pathway is activated that inhibits subsequent nodule development in the root. In Medicago truncatula, MtCLE35 is activated in response to rhizobia and nitrate treatment and the overexpression of this gene systemically inhibits nodulation. The inhibitory effect of MtCLE35 overexpression is dependent on the CLV1-like receptor kinase MtSUNN (SUPER NUMERIC NODULES), suggesting that MtSUNN could be involved in the reception of the MtCLE35 peptide. Yet little is known about the downstream genes regulated by a MtCLE35-activated response in the root. In order to identify genes whose expression levels could be regulated by the MtCLE35-MtSUNN pathway, we performed a MACE-Seq (Massive Analysis of cDNA Ends) transcriptomic analysis of MtCLE35-overexpressing roots. Among upregulated genes, the gene MtSUNN that encodes a putative receptor of MtCLE35 was detected. Moreover, we found that MtSUNN, as well as several other differentially expressed genes, were upregulated locally in MtCLE35-overexpressing roots whereas the MtTML1 and MtTML2 genes were upregulated systemically. Our data suggest that MtCLE35 has both local and systemic effects on target genes in the root.

Polymorphism of CLE gene sequences in potato.

CLE (CLV3/ESR) is one of the most important groups of peptide phytohormones: its members regulate the development of various plant organs and tissues, as well as interaction with some parasites and symbionts and response to environmental factors. In this regard, the identif ication and study of the CLE genes encoding the peptides of this group in cultivated plants are of great practical interest. Relatively little is known about the functions of CLE peptides in potato, since the CLE genes of the potato Solanum phureja Juz. et Buk. were characterized only in 2021. At the same time, potato includes plenty of tuberous species of the genus Solanum L., both wild and cultivated, and the diversity of its forms may depend on differences in the sequences of CLE genes. In this work, we performed a search for and analysis of the CLE gene sequences in three wild potato species (S. bukasovii Juz., S. verrucosum Schltdl., S. commersonii Dunal) and four cultivated species (S. chaucha Juz. et Buk., S. curtilobum Juz. et Buk., S. juzepczukii Juz. et Buk., S. ajanhuiri Juz. et Buk.). In total, we identif ied 332 CLE genes in the analyzed potato species: from 40 to 43 genes of this family for each potato species. All potato species taken for analysis had homologues of previously identif ied S. phureja CLE genes; at the same time, the CLE42 gene, which is absent from the S. phureja genome, is present in all other analyzed potato species. Polymorphism of CLE proteins of S. commersonii is signif icantly higher than that of other analyzed potato species, due to the fact that S. commersonii grows in places outside the growing areas of other potato species and this potato is probably not one of the ancestors of cultivated potato. We also found examples of polymorphism of domains of CLE proteins that carried different tions. Further study of potato CLE proteins will reveal their role in development, including regulation of productivity in this important agricultural crop.

[What Does the WOX Say? Review of Regulators, Targets, Partners].

WOX (WUSCHEL-RELATED HOMEOBOX) is a family of homeodomain-containing transcription factors in plants. WOX proteins maintain the activity of different types of meristems and regulate the formation of plant organs, controlling cell proliferation and differentiation. Study of the WOX family is important for the development of plant transformation and genome editing techniques. Here we review the functions of the WOX transcription factors as well as their targets, partners, and regulators. The WOX family can be divided into three phylogenetically distinct clades; so-called ancient, intermediate, and WUS clade; each clade is covered in a separate section. The WOX genes of Arabidopsis thaliana are described most comprehensively, with their orthologs in other plant species also considered. Summary tables with the described targets, regulators and partners of WOX family members are provided.

[Plant-Producers Of Recombinant Cytokines (Review)].

Cytokines are a family of signaling polypeptides involved in cell-cell interactions in the process of the immune response, as well as in the regulation of a number of normal physiological functions. Cytokines are used in medicine for the treatment of cancer, immune disorders, viral infections, and other socially significant diseases, but the extent of their use is limited by the high production cost of the active agent. The development of this area of pharmacology is associated with the success of genetic engineering, which allows the production of significant amounts of protein by transgenic organisms. The review discusses the latest advances in the production of various cytokines with the use of genetically modified plants.

Plant Based Bioreactors of Recombinant Cytokines (Review).

Cytokines are a family of signaling polypeptides involved in intercellular interactions in the process of the immune response, as well as in the regulation of a number of normal physiological functions. Cytokines are used in medicine for the treatment of cancer, immune disorders, viral infections, and other socially significant diseases, but the extent of their use is limited by the high production cost of the active agent. The development of this area of pharmacology is associated with the success of genetic engineering, which allows the production of significant amounts of protein by transgenic organisms. The review discusses the latest advances in the production of various cytokines with the use of genetically modified plants.

KNOTTED1-LIKE HOMEOBOX 3: a new regulator of symbiotic nodule development.

KNOX transcription factors (TFs) regulate different aspects of plant development essentially through their effects on phytohormone metabolism. In particular, KNOX TF SHOOTMERISTEMLESS activates the cytokinin biosynthesis ISOPENTENYL TRANSFERASE (IPT) genes in the shoot apical meristem. However, the role of KNOX TFs in symbiotic nodule development and their possible effects on phytohormone metabolism during nodulation have not been studied to date. Cytokinin is a well-known regulator of nodule development, playing the key role in the regulation of cell division during nodule primordium formation. Recently, the activation of IPT genes was shown to take place during nodulation. Therefore, it was hypothesized that KNOX TFs may regulate nodule development and activate cytokinin biosynthesis upon nodulation. This study analysed the expression of different KNOX genes in Medicago truncatula Gaertn. and Pisum sativum L. Among them, the KNOX3 gene was upregulated in response to rhizobial inoculation in both species. pKNOX3::GUS activity was observed in developing nodule primordium. KNOX3 ectopic expression caused the formation of nodule-like structures on transgenic root without bacterial inoculation, a phenotype similar to one described previously for legumes with constitutive activation of the cytokinin receptor. Furthermore, in transgenic roots with MtKNOX3 knockdown, downregulation of A-type cytokinin response genes was found, as well as the MtIPT3 and LONELYGUY2 (MtLOG2) gene being involved in cytokinin activation. Taken together, these findings suggest that KNOX3 gene is involved in symbiotic nodule development and may regulate cytokinin biosynthesis/activation upon nodule development in legume plants.

[Transcription Factors in Developmental Genetics and the Evolution of Higher Plants].

Transcription factors play an essential role in controlling various developmental programs in plants, coordinating the action of any genetic network. Among the most important groups of plant transcription factors are the homeodomain-containing transcription factors, in particular, those belonging to the KNOX and WOX families, the functions of which are associated with regulation of the meristem activity, development of the aboveground and underground parts of plants, and control of embryogenesis. This review examines the role of KNOX and WOX transcription factors in various developmental programs, as well as in the evolutionary complication of the body plan in terrestrial plants.

[Opine biosynthesis and catabolism genes of Agrobacterium tumefaciens and Agrobacterium rhizogenes].

Agrobacterium is a genus of soil bacteria with the ability to transform plant cells by a T-DNA-sequence located on the pTi/pRi- plasmid containing a set of genes expressed in plant cells. Expression of these genes leads to a proliferation of transformed cells, with the subsequent formation of tumors or growths of roots and the synthesis of opines--products of the condensation of amino acids with ketoacids or sugars used by Agrobacteria as a source of carbon and nitrogen. In this review, we systematized the information about most common opines in plant--Agrobacterium systems and their biosynthesis and catabolism genes, as well as the role of opines in the interaction of pathogenic Agrobacterium with plants and with other Agrobacterium strains, including the genetic consequences of such interactions.

[Meristematic characteristics of tumors initiated by Agrobacterium tumefaciens in pea plants].

It is known that two key groups of plant hormones--auxins and cytokinins--play an important role in plant tumor development. The formation of Agrobacterium-induced tumors results from the horizontal transfer of bacterial oncogenes involved in the biosynthesis of these hormones in the plant genome. The role of transcriptional factors in plant tumor development is poorly investigated. It can be assumed that tumor development associated with abnormal cell proliferation can be controlled by the same set of transcription factors that control normal cell proliferation and, in particular, transcription factors that regulate meristem activity. In the present study, we analyzed the histological organization and distribution of proliferating cells in tumors induced by Agrobacterium tumefaciens on pea hypocotyls. In addition, the expression of a set of meristem-specific genes with Agrobacterium tumefaciens-induced tumor development was analyzed. In general, our results indicate that meristematic structures are present in A. tumefaciens-induced tumors and that the development of such tumors is associated with increased expression of a key gene regulating the root apical meristem--the WOX5 gene.

[Expression of the WOX and PIN Genes in the Course of Somatic and Zygotic Embryogenesis of a Medicago truncatula].

Comparative analysis of the expression of the WOXand PINgenes in ovules and in the course of somatic embryogenesis of Medicago truncatula Gaertn was performed. It was shown that some WOX and PIN genes that had an increased expression level in ovules (MtWOX11-like, STENOFOLIA, MTR_2g015000, and MtPIN10) were also activated in the course of somatic embryogenesis. At the same time, the WOX and PIN genes, the expression level of which was low in ovules, did not show transcription activation associated with somatic embryogenesis. These data allow the assumption that the same regulatory mechanisms can be involved in the control of the early stages of somatic and zygotic embryogenesis.

[Features of the expression of a meristem-specific WOX5 gene during nodule organogenesis in legumes].

In recent years, the role of WOX genes encoding homeodomain transcription factors in the development of the apical meristem of shoots and roots has been actively investigated. However, the role of WOX genes in the control of the cell proliferation in other meristem types is poorly studied. In our work, we have studied the role of the WOX5 gene in the development of the meristem in nitrogen-fixing nodules developing on the roots of legumes in a symbiosis with rhizobia. We have shown that the WOX5 gene is involved in the development of the nodule meristem in legumes, have quantitatively evaluated the gene's expression at different nodule formation stages, and have studied the localization of its expression using a construction containing the WOX5 promoter conjugated with a reporter gene. The role of the WOX5 transcription factor in the nodule organogenesis and its possible interaction with the hormonal system in the course of the nodule development has been discussed.

[Investigation of systemic control of plant cell division and differentiation in the model of tumor growth in radish].

The study addresses the control of plant cell division and differentiation using the model of tumor-forming lines of radish. Expression of the genes involved in control of the cell cycle (CycD3), maintenance of meristematic cell activity (STM, WUS, and KNAT1), and primary response to cytokinin (ARR) was studied in inbred radish lines characterized by tumor growth at different stages of development. The influence of exogenic cytokinin on the expression of the genes of interest is analyzed. The possible role of the CycD3, KNAT1, STM, WUS, and ARR5 in tumor formation in radish is discussed.

[The genetic collection of radish inbred lines: history and prospects].

The characteristics of a unique genetic collection of radish inbred lines and the history of its creation and study are presented. The possible research prospects are discussed.

[Role of meristem-specific genes of plants in formation of genetic tumors].

In higher plants, homeobox genes of the KNOX and WOX subfamilies plays a key role in maintenance of the pool of stem cells, regulate proliferation, and prevent cell differentiation. It has been shown that meristem-specific genes are regulated by phytohormones and affect their metabolism, specifically that of cytokinins. Plant tumors are widely used as a model for studying the genetic control of cell division and differentiation. The tumors induced by pathogens and genetic tumors, whose development depends on the plant genotype, are distinguished. The changes in the levels of expression of genes--regulators of cell cycle, meristem-specific genes, and genes controlling metabolism and transmission of the signal of phytohormones were described on tumors of different origin. The mechanisms underlying tumor formation in plants and animals were shown to be similar, specifically as concerns the relationship between the genes--cell cycle regulators and tumorigenesis. In plants, transcriptional factors of the subfamily KNOX have similarity in structure and, supposedly, common origin with transcriptional factors MEIS in animals, which are very active in neoplastic cells. The review presents the characteristics of KNOX and WOX transcriptional factors, their functions in meristem development, and interaction with the plant hormonal system. The role of homeodomain-containing transcriptional factors in tumorigenesis in plants and animals is discussed. The role of meristem-specific genes and phytohormones in tumorigenesis is discussed on the example of genetic tumors obtained by mutagenesis in Arabidopsis thaliana and tumors in the radish inbred lines.

[Tumor formation in plants]. / Opukholeobrazovanie u rastenii.

The data on genetic tumors in plant species and interspecific hybrids, as well as the problems of Agrobacterium-induced tumors are reviewed. The role of the horizontal gene transfer in the induction of genetic tumors is discussed.

[Nodulation as a model for studying differentiation in higher plants]. / Kluben'koobrazovanie kak model' dlia izucheniia differentsirovki u vysshikh rastenii.

The stages of the legume-rhizobial symbiosis and nodule structure in various legume plants are briefly reviewed. Modern data on the mechanisms involved in the control of nodule initiation and morphogenesis are considered.

[Characteristics of certain symbiotic pea mutants by traits related to hormonal status]. / Kharakteristikia nekotorykh simbioticheskikh mutantov gorokha po priznakam, sviazannym s gormonal'nym statusom.

Association between traits for hormonal status and nodulation in the mutants of pea Pisum sativum L. with abnormal nodulation and original forms was analyzed. The sensitivity of plant tissues to exogenous phytohormones and changes in the concentration of the major auxin, indolyl-3-acetic acid, in plant roots during interaction with rhizobia were examined. Association between Nod(++)-phenotype and auxin balance was revealed: the supernodulating mutants were more sensitive to auxin treatment than the parental cultivars. Mutations in the sym8 gene, in contrast to those in the sym5 gene, had no effect on plant hormonal status. The level of indolyl-3-acetic acid during interaction with rhizobia depended on the time after inoculation and plant genotype. The mutations affecting nodulation were suggested to change auxin level in roots.

[The role of phytohormones in tumor formation in radish]. / Izuchenie roli fitogormonov v protsesse opukholeobrazovaniia u redisa.

Tumor formation was studied in inbred radish lines that produce tumors on plant roots during flowering. In all radish lines under consideration, the sequences homologous to oncogenes tmr/tml of Agrobacterium tumefaciens were revealed by Southern hybridization. No sequences homologous to the tms locus of A. tumefaciens and the oncogenes of A. rhizogenes were determined. It was found that auxin sensitivity and the tumor-producing capacity were coinherited. We suggest that tumor phenotype arise as a result of a combination between agrobacterial "cytokinin" oncogenes and certain alleles of "auxin" radish genes.

[Effect of azacytidine on expression of traits concomitant with tumor formation in the radish (Raphanus sativus) in vitro]. / Vliianie azatsitidina na proiavlenie priznakov, soputstvuiushchikh opukholeobrazovaniiu, u redisa (Raphanus sativus) in vitro.

The effect of azacytidine, a demethylating agent, on the expression of traits concomitant with tumor formation was studied in inbred radish (Rhaphanus sativus) lines carrying genomic sequences homologous to the tmr/tml genes of Agrobacteriium tumefaciens. AzaC was found to have no effect on the traits studied, which provided evidence that the capacity for tumor formation in radish lines does not depend on the level of methylation of these sequences.

Nucleosomal structure and histone H1 subfractional composition of pea (Pisum sativum) root nodules, radicles and callus chromatin.

Higher-order packaging of DNA in chromatin structures could be an essential step in the complex chain of events leading to activation/repression of eukaryotic gene expression. With the goal to investigate this aspect of transcriptional regulation of plant genes involved in symbiotic interactions between legumes and rhizobia we analyze here the molecular parameters of chromatin structure in functioning root nodules, callus and radicles of pea. Morphological intactness and the typical nucleosomal organization are preserved in purified nuclei isolated from all three sources. The calculated values of nucleosomal repeat changed from 185 +/- 5 bp in the nuclei of radicles to 168 +/- 5 bp and 195 +/- 6 bp in nodules and callus respectively. The observed changes are due to alterations in linker DNA lengths. The core histones are identical in all cases, but the subfractional composition of H1 linker histone is subjected to quantitative alterations. The most pronounced is the several-fold increase in content of the lowest-molecular-weight subfraction H1-6 which takes place during nodule development.