Members Of Two-component Systems Research Articles

Genome-wide identification and expression analysis of two-component system genes in switchgrass (Panicum virgatum L.)

The two-component system (TCS) consists of histidine kinase (HK), histidine phosphate transfer protein (HP), and response regulatory factor (RR). It is one of the most crucial components of signal transduction in plants, playing a significant role in regulating plant growth, development, and responses to various abiotic stresses. Although TCS genes have been extensively identified in a variety of plants, the genome-wide recognition and examination of TCS in switchgrass remain unreported. Accordingly, this study identified a total of 87 TCS members in the genome of switchgrass, comprising 20 HK(L)s, 10 HPs, and 57 RRs. Detailed analyses were also conducted on their gene structures, conserved domains, and phylogenetic relationships. Moreover, this study analysed the gene expression profiles across diverse organs and investigated their response patterns to adverse environmental stresses. Results revealed that 87 TCS genes were distributed across 18 chromosomes, with uneven distribution. Expansion of these genes in switchgrass was achieved through both fragment and tandem duplication. PvTCS members are relatively conservative in the evolutionary process, but the gene structure varies significantly. Various cis-acting elements, varying in types and amounts, are present in the promoter region of PvTCSs, all related to plant growth, development, and abiotic stress, due to the TCS gene structure. Protein-protein interaction and microRNA prediction suggest complex interactions and transcriptional regulation among TCS members. Additionally, most TCS members are expressed in roots and stems, with some genes showing organ-specific expression at different stages of leaf and inflorescence development. Under conditions of abiotic stress such as drought, low temperature, high temperature, and salt stress, as well as exogenous abscisic acid (ABA), the expression of most TCS genes is either stimulated or inhibited. Our systematic analysis could offer insight into the characterization of the TCS genes, and further the growth of functional studies in switchgrass.

Genome-wide identification and expression analysis of two-component system genes in sweet potato (Ipomoea batatas L.).

Two-component system (TCS), which comprises histidine kinases (HKs), histidine phosphotransfer proteins (HPs), and response regulators (RRs), plays essential roles in regulating plant growth, development, and response to various environmental stimuli. TCS genes have been comprehensively identified in various plants, while studies on the genome-wide identification and analysis of TCS in sweet potato were still not reported. Therefore, in this study, a total of 90 TCS members consisting of 20 HK(L)s, 11 HPs, and 59 RRs were identified in the genome of Ipomoea batatas. Furthermore, their gene structures, conserved domains, and phylogenetic relationships were analyzed in detail. Additionally, the gene expression profiles in various organs were analyzed, and response patterns to adverse environmental stresses were investigated. The results showed that these 90 TCS genes were mapped on 15 chromosomes with a notably uneven distribution, and the expansion of TCS genes in sweet potato was attributed to both segmental and tandem duplications. The majority of the TCS genes showed distinct organ-specific expression profiles, especially in three types of roots (stem roots, fibrous roots, tuberous roots). Moreover, most of the TCS genes were either induced or suppressed upon treatment with abiotic stresses (drought, salinity, cold, heat) and exogenous phytohormone abscisic acid (ABA). In addition, the yeast-two hybrid system was used to reveal the HK-HP-RR protein-protein interactions. IbHP1, IbHP2, IbHP4, and IbHP5 could interact with three HKs (IbHK1a, IbHK1b, and IbHK5), and also interact with majority of the type-B RRs (IbRR20-IbRR28), while no interaction affinity was detected for IbHP3. Our systematic analyses could provide insights into the characterization of the TCS genes, and further the development of functional studies in sweet potato.

Characterization and virulence of Streptococcus agalactiae deficient in SaeRS of the two-component system.

There are a variety of regulatory systems in bacteria, among which the two-component system (TCS) can sense external environmental changes and make a series of physiological and biochemical reactions, which is crucial for the life activities of bacteria. As a member of TCS, SaeRS is considered to be an important virulence factor in Staphylococcus aureus, but its function in tilapia (Oreochromis niloticus)-derived Streptococcus agalactiae remains unknown. To explore the role of SaeRS in regulating virulence in the two-component system (TCS) of S. agalactiae from tilapia, ΔSaeRS mutant strain and CΔSaeRS complementary strain were constructed by homologous recombination. The results showed that the abilities of growth and biofilm formation of ΔSaeRS strain were significantly decreased when cultured in a brain heart infusion (BHI) medium (P < 0.01). Also, the survival rate of the ΔSaeRS strain in blood was decreased when compared with the wild strain S. agalactiae THN0901. Under the higher infection dose, the accumulative mortality of tilapia caused by the ΔSaeRS strain was significantly decreased (23.3%), of which THN0901 and CΔSaeRS strains were 73.3%. The results of competition experiments in tilapia showed that the invasion and colonization abilities of the ΔSaeRS strain were also dramatically lower than those of the wild strain (P < 0.01). Compared with the THN0901, the mRNA expression levels of virulence factors (fbsB, sip, cylE, bca, etc.) in the ΔSaeRS strain were significantly down-regulated (P < 0.01). SaeRS is one of the virulence factors of S. agalactiae. It plays a role in promoting host colonization and achieving immune evasion during the infection of tilapia, which provides a basis for exploring the pathogenic mechanism of S. agalactiae infected with tilapia.

Expression alteration analyses in the transgenic Arabidopsis carrying soybean Histidine-containing phosphotransmitter gene under salinity stress condition

Productivity of many crops is highly vulnerable to extreme external conditions. Environmental stress factors such as drought and salinity have become more and more serious due to climate change and appear in many areas worldwide with higher frequency. As both drought and salinity belong to osmotic stress, they have similar negative effects on plant growth, development, and productivity as well as trigger similar stress responses by plants. In a previous study analyzing the expression profile in two soybean (Glycine max) cultivars with contrasting drought-tolerant phenotypes, a member of two-component system (TCS) in soybean, GmHP08, was proposed to associate with the plant tolerance capacity to drought. Subsequent in planta study confirmed its action as a positive regulator under drought conditions, as the transgenic Arabidopsis plants ectopically expressing GmHP08 acquired better drought tolerance. Following this, the presented research further explored the possible function of GmHP08 in mediating plant response to salinity. The obtained data from RT-qPCR analyses suggested that GmHP08 might positively enhance the salt tolerance of the Arabidopsis transgenic plants by altering the transcriptional abundance of several stress-related genes, including RD29A, RD29B, ABI5, SAG13, and CSD1. Activities of these genes are known to be associated with osmoprotection, senescence process, and antioxidation, which contribute to salt-tolerance ability of the transgenic plants. These results provided the first line of molecular evidence regarding GmHP08 function in plant response to salinity conditions. Therefore, extensive studies should be conducted in future studies to elaborate on the mechanisms by which this TCS member could improve various types of osmotic stress tolerance in plants.

Genome-wide identification and interactome analysis of members of two-component system in Banana

BackgroundEthylene signal transduction in plants is conducted by the two-component system (TCS) which consists of histidine kinase (HK), histidine phosphotransferase (HPT) and response regulators (RRs). This system plays an important role in signal transduction during various cellular processes, including fruit ripening and response to multiple environmental cues. Though members of TCS have been identified in a few plants, no detailed analysis has been carried out in banana.ResultsThrough genome-wide analysis, we identified a total of 80 (25 HK, 10 HPT and 45 RR) and 72 (25 HK, 5 HPT and 42 RR) TCS genes in Musa acuminata and Musa balbisiana respectively. The analysis of identified genes revealed that most of the genes are highly conserved however; there are subtle divergences among various members. Comparative expression analysis revealed an involvement of a set of TCS members during banana fruit ripening. Co-expression network analysis identified a working TCS module with direct interactions of HK-HPT and RR members. The molecular dynamics analysis of TCS module showed a significant change in structural trajectories of TCS proteins in the presence of ethylene. Analysis suggests possible interactions between the HK-HPTs and RRs as well as other members leading to banana fruit ripening.ConclusionsIn this study, we identified and compared the members of TCS gene family in two banana species and showed their diversity, within groups on the basis of whole-genome duplication events. Our analysis showed that during banana fruit ripening TCS module plays a crucial role. We also demonstrated a possible interaction mechanism of TCS proteins in the presence and absence of ethylene by molecular dynamics simulations. These findings will help in understanding the functional mechanism of TCS proteins in plants in different conditions.

ARR22 overexpression can suppress plant Two-Component Regulatory Systems.

In plants, several developmental processes are co-coordinated by cytokinins via phosphorylation dependent processes of the Two-Component System (TCS). An outstanding challenge is to track phosphorelay flow from cytokinin perception to its molecular outputs, of which gene activation plays a major role. To address this issue, a kinetic-based reporter system was expounded to track TCS phosphorelay activity in vivo that can distinguish between basal and cytokinin dependent effects of overexpressed TCS members. The TCS phosphorelay can be positively activated by cytokinin and inhibited by pharmaceuticals or naturally interfering components. In this case we took advantage of the phosphohistidine-phosphatase Arabidopsis Response Regulator (ARR) 22 and investigated its phosphocompetition with other TCS members in regulating promoters of ARR5 and WUS in Arabidopsis thaliana cell culture protoplasts. In congruency with the proposed function of ARR22, overexpression of ARR22 blocked the activation of all B-type ARRs in this study in a TCS dependent manner. Furthermore, this effect could not be mimicked by A-type response regulator overexpression or compensated by AHP overexpression. Compared to other reporter assays, ours mimicked effects previously observed only in transgenic plants for all of the TCS proteins studied, suggesting that it is possible to expose phosphocompetition. Thus, our approach can be used to investigate gene signaling networks involving the TCS by leveraging ARR22 as a TCS inhibitor along with B-type ARR overexpression.

Genome-Wide Identification of Two-Component Signal Transduction System Genes in Melon (&amp;lt;I&amp;gt;Cucumis melon&amp;lt;/I&amp;gt; L.)

Two-component system (TCS) is responsible for cytokinin signaling, which plays critical roles in plant development and physiological process. This system is generally composed of two signaling factors, a histidine kinase (HK) and a response regulator (RR) that is associated with a histidine phosphotransfer (HP) protein. In this study, we performed systematic investigation on TCS genes in melon (Cucumis melon L.). We identified 44 TCS genes in melon, including 18 HK(L)s (9 HKs and 9 HKLs), 5 HPs (4 authentic and 1 pseudo), and 21 RRs (7 Type-A, 8 Type-B, and 6 pseudo). The classification and structure of these melon TCS members were introduced in detail as well. Our results provided new insights into the characteristics of the melon TCS genes and might benefit their functional study in future.

Mapping the \u2018Two-component system\u2019 network in rice

Two-component system (TCS) in plants is a histidine to aspartate phosphorelay based signaling system. Rice genome has multifarious TCS signaling machinery comprising of 11 histidine kinases (OsHKs), 5 histidine phosphotransferases (OsHPTs) and 36 response regulators (OsRRs). However, how these TCS members interact with each other and comprehend diverse signaling cascades remains unmapped. Using a highly stringent yeast two-hybrid (Y2H) platform and extensive in planta bimolecular fluorescence complementation (BiFC) assays, distinct arrays of interaction between various TCS proteins have been identified in the present study. Based on these results, an interactome map of TCS proteins has been assembled. This map clearly shows a cross talk in signaling, mediated by different sensory OsHKs. It also highlights OsHPTs as the interaction hubs, which interact with OsRRs, mostly in a redundant fashion. Remarkably, interactions between type-A and type-B OsRRs have also been revealed for the first time. These observations suggest that feedback regulation by type-A OsRRs may also be mediated by interference in signaling at the level of type-B OsRRs, in addition to OsHPTs, as known previously. The interactome map presented here provides a starting point for in-depth molecular investigations for signal(s) transmitted by various TCS modules into diverse biological processes.

Genome-Wide Identification of Two-Component System Genes in Cucurbitaceae Crops and Expression Profiling Analyses in Cucumber.

Cucumber and watermelon, which belong to Cucurbitaceae family, are economically important cultivated crops worldwide. However, these crops are vulnerable to various adverse environments. Two-component system (TCS), consisting of histidine kinases (HKs), phosphotransfers (HPs), and response regulator proteins (RRs), plays important roles in various plant developmental processes and signaling transduction in responses to a wide range of biotic and abiotic stresses. No systematic investigation has been conducted on TCS genes in Cucurbitaceae species. Based on the completion of the cucumber and watermelon genome draft, we identified 46 and 49 TCS genes in cucumber and watermelon, respectively. The cucumber TCS members included 18 HK(L)s, 7 HPs, and 21 RRs, whereas the watermelon TCS system consisted of 19 HK(L)s, 6 HPs, and 24 RRs. The sequences and domains of TCS members from these two species were highly conserved. Gene duplication events occurred rarely, which might have resulted from the absence of recent whole-genome duplication event in these two Cucurbitaceae crops. Numerous stress- and hormone-responsive cis-elements were detected in the putative promoter regions of the cucumber TCS genes. Meanwhile, quantitative real-time PCR indicated that most of the TCS genes in cucumber were specifically or preferentially expressed in certain tissues or organs, especially in the early developing fruit. Some TCS genes exhibited diverse patterns of gene expression in response to abiotic stresses as well as exogenous trans-zeatin (ZT) and abscisic acid (ABA) treatment, suggesting that TCS genes might play significant roles in responses to various abiotic stresses and hormones in Cucurbitaceae crops.

Identification of an interaction between EI and a histidine kinase-response regulator hybrid protein in Gluconobacter oxydans

Gluconobacter oxydans may contain an incomplete phosphoenolpyruvate: carbohydrate phosphotransferase system consisting of three components - EI, HPr and EIIA, while the function of individual members of the system remains unknown. In this research, a specific interaction between EI and a histidine kinase-response regulator hybrid protein was screened by yeast two-hybrid assay, and the interaction was further identified with GST pull-down assay and bimolecular fluorescence complementation assay in vitro and in vivo, respectively. As the histidine kinase-response regulator hybrid protein serves as a member of two-component system in G. oxydans, its interaction with EI implied that PTS may play certain roles in bacteria under stress.

Tissue specific and abiotic stress regulated transcription of histidine kinases in plants is also influenced by diurnal rhythm

Two-component system (TCS) is one of the key signal sensing machinery which enables species to sense environmental stimuli. It essentially comprises of three major components, sensory histidine kinase proteins (HKs), histidine phosphotransfer proteins (Hpts), and response regulator proteins (RRs). The members of the TCS family have already been identified in Arabidopsis and rice but the knowledge about their functional indulgence during various abiotic stress conditions remains meager. Current study is an attempt to carry out comprehensive analysis of the expression of TCS members in response to various abiotic stress conditions and in various plant tissues in Arabidopsis and rice using MPSS and publicly available microarray data. The analysis suggests that despite having almost similar number of genes, rice expresses higher number of TCS members during various abiotic stress conditions than Arabidopsis. We found that the TCS machinery is regulated by not only various abiotic stresses, but also by the tissue specificity. Analysis of expression of some representative members of TCS gene family showed their regulation by the diurnal cycle in rice seedlings, thus bringing-in another level of their transcriptional control. Thus, we report a highly complex and tight regulatory network of TCS members, as influenced by the tissue, abiotic stress signal, and diurnal rhythm. The insights on the comparative expression analysis presented in this study may provide crucial leads toward dissection of diverse role(s) of the various TCS family members in Arabidopsis and rice.

Differential gene expression in soybean leaf tissues at late developmental stages under drought stress revealed by genome-wide transcriptome analysis.

The availability of complete genome sequence of soybean has allowed research community to design the 66 K Affymetrix Soybean Array GeneChip for genome-wide expression profiling of soybean. In this study, we carried out microarray analysis of leaf tissues of soybean plants, which were subjected to drought stress from late vegetative V6 and from full bloom reproductive R2 stages. Our data analyses showed that out of 46093 soybean genes, which were predicted with high confidence among approximately 66000 putative genes, 41059 genes could be assigned with a known function. Using the criteria of a ratio change > = 2 and a q-value<0.05, we identified 1458 and 1818 upregulated and 1582 and 1688 downregulated genes in drought-stressed V6 and R2 leaves, respectively. These datasets were classified into 19 most abundant biological categories with similar proportions. There were only 612 and 463 genes that were overlapped among the upregulated and downregulated genes, respectively, in both stages, suggesting that both conserved and unconserved pathways might be involved in regulation of drought response in different stages of plant development. A comparative expression analysis using our datasets and that of drought stressed Arabidopsis leaves revealed the existence of both conserved and species-specific mechanisms that regulate drought responses. Many upregulated genes encode either regulatory proteins, such as transcription factors, including those with high homology to Arabidopsis DREB, NAC, AREB and ZAT/STZ transcription factors, kinases and two-component system members, or functional proteins, e.g. late embryogenesis-abundant proteins, glycosyltransferases, glycoside hydrolases, defensins and glyoxalase I family proteins. A detailed analysis of the GmNAC family and the hormone-related gene category showed that expression of many GmNAC and hormone-related genes was altered by drought in V6 and/or R2 leaves. Additionally, the downregulation of many photosynthesis-related genes, which contribute to growth retardation under drought stress, may serve as an adaptive mechanism for plant survival. This study has identified excellent drought-responsive candidate genes for in-depth characterization and future development of improved drought-tolerant transgenic soybeans.

Whole-Genome Analysis of Oryza sativa Reveals Similar Architecture of Two-Component Signaling Machinery with Arabidopsis

The two-component system (TCS), which works on the principle of histidine-aspartate phosphorelay signaling, is known to play an important role in diverse physiological processes in lower organisms and has recently emerged as an important signaling system in plants. Employing the tools of bioinformatics, we have characterized TCS signaling candidate genes in the genome of Oryza sativa L. subsp. japonica. We present a complete overview of TCS gene families in O. sativa, including gene structures, conserved motifs, chromosome locations, and phylogeny. Our analysis indicates a total of 51 genes encoding 73 putative TCS proteins. Fourteen genes encode 22 putative histidine kinases with a conserved histidine and other typical histidine kinase signature sequences, five phosphotransfer genes encoding seven phosphotransfer proteins, and 32 response regulator genes encoding 44 proteins. The variations seen between gene and protein numbers are assumed to result from alternative splicing. These putative proteins have high homology with TCS members that have been shown experimentally to participate in several important physiological phenomena in plants, such as ethylene and cytokinin signaling and phytochrome-mediated responses to light. We conclude that the overall architecture of the TCS machinery in O. sativa and Arabidopsis thaliana is similar, and our analysis provides insights into the conservation and divergence of this important signaling machinery in higher plants.