Protein Acetylation Mediated by YfiQ and CobB Is Involved in the Virulence and Stress II
ABSTRACT: Our comparative transcriptomic studies found that the cobB and yfiQ deletions resulted in differential expression of a large number of genes,we found 399 DEGs in the cobB mutant, among which 142 were down-regulated and 257 were up-regulated and there were 594 DEGs in the yfiQ mutant, among which 219 were down-regulated and 375 were up-regulated in comparison with the Yersinia pestis wild-type strain.Interestingly, expression of the virulence-related genes hmsHFRS, psaABEF were significantly lower in both ΔcobB and ΔyfiQ. Moreover, the stress response-related genes involved in the heat- and cold-shock response, acid resistance, and the universal stress response were significantly differentially expressed.most of these genes were expressed at significantly lower levels than in the wild-type strain.The mouse infection experiments and the phenotype analysis confirmedthe virulence attenuation of ΔcobB and ΔyfiQ. Our results demonstrate that protein acetylation mediated by YfiQ and CobB is involved in the virulence and stress. Overall design: We compared the transcriptional profiles of the cobB and yfiQ mutants with that of the wild-type strain using RNA-sequencing (RNA-seq)
Project description:NAC domain genes belong to a large plant-specific transcription factor family, which is well-known to be associated with multiple stress responses and plant developmental processes. In this study, we screened differentially expressed genes (DEGs) and detected mRNA abundance of NAC family by RNA-Seq in the poplar leaves under salt stress condition. A total of 276 up-regulated DEGs and 159 down-regulated DEGs were identified to be shared in Populus alba × Populus glandulosa and Populus simonii × Populus nigra. Among 170 NAC members, NAC57 gene was significantly up-regulated in response to salt stress in the two species. Tissue-specific and salt-responsive analyses indicated the expression pattern of NAC57 gene was spatial and temporal in poplar under salt stress. Particle bombardment results showed subcellular localization of NAC57 was not solely nucleus-targeted. Full-length cDNA sequence of the NAC57 gene was cloned from P. alba × P. glandulosa and transformed into Arabidopsis thaliana. Under salt stress, transgenic Arabidopsis overexpressing NAC57 showed higher seed germination rate, root length, and fresh weight than wild type plants. In addition, the transgenic plants displayed higher superoxide dismutase activity and peroxidase activity, and lower malondialdehyde content and relative electrical conductivity than the wild type under salt stress condition. Furthermore, histochemical staining indicated reactive oxygen species accumulation was lower in the transgenic plants than that in the wild type under salt stress. All the results indicated that the NAC57 gene plays an important role in salt stress responses.
Project description:BACKGROUND:Heat stroke (HS) is a physically dysfunctional illness caused by hyperthermia. Lung, as the important place for gas-exchange and heat-dissipation organ, is often first to be injured. Lung injury caused by HS impairs the ventilation function of lung, which will subsequently cause damage to other tissues and organs. Nevertheless, the specific mechanism of lung injury in heat stroke is still unknown. METHODS:Rat lung tissues from controls or HS models were harvested. The gene expression profile was identified by high-throughput sequencing. DEGs were calculated using R and validated by qRT-PCR. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and cell-enrichment were performed using differential expression genes (DEGs). Finally, lung histopathology was accessed by H&E staining. RESULTS:About 471 genes were identified to be DEGs, of which 257 genes were up-regulated, and 214 genes were down-regulated. The most up-regulated and down-regulated DEGs were validated by qRT-PCR, which confirmed the tendency of expression. GO, KEGG, and protein-protein interaction (PPI)-network analyses disclosed DEGs were significantly enriched in leukocyte migration, response to lipopolysaccharide, NIK/NF-kappaB signaling, response to reactive oxygen species, response to heat, and the hub genes were Tnf, Il1b, Cxcl2, Ccl2, Mmp9, Timp1, Hmox1, Serpine1, Mmp8 and Csf1, most of which were closely related to inflammagenesis and oxidative stress. Finally, cell-enrichment analysis and histopathologic analysis showed Monocytes, Megakaryotyes, and Macrophages were enriched in response to heat stress. CONCLUSIONS:The present study identified key genes, signal pathways and infiltrated-cell types in lung after heat stress, which will deepen our understanding of transcriptional response to heat stress, and might provide new ideas for the treatment of HS.
Project description:BACKGROUND:Cucumber Fusarium wilt, caused by Fusarium oxysporum f. sp. cucumerinum (Foc), is one of the most notorious diseases in cucumber production. Our previous research showed the virulence of Foc significantly increases over consecutive rounds of infection in a resistant cultivar. To understand the virulence variation of Foc under host pressure, the mildly virulent strain foc-3b (WT) and its virulence-enhanced variant Ra-4 (InVir) were selected and their transcriptome profiles in infected cucumber roots were analyzed at 24?h after inoculation (hai) and 120?hai. RESULTS:A series of differentially expressed genes (DEGs) potentially involved in fungal pathogenicity and pathogenicity variation were identified and prove mainly involved in metabolic, transport, oxidation-reduction, cell wall degradation, macromolecules modification, and stress and defense. Among these DEGs, 190 up- and 360 down-regulated genes were expressed in both strains, indicating their importance in Foc infection. Besides, 286 and 366 DEGs showed up-regulated expression, while 492 and 214 showed down-regulated expression in InVir at 24 and 120?hai, respectively. These DEGs may be involved in increased virulence. Notably, transposases were more active in InVir than WT, indicating transposons may contribute to adaptive evolution. CONCLUSIONS:By a comparative transcriptome analysis of the mildly and highly virulent strains of Foc during infection of cucumber, a series of DEGs were identified that may be associated with virulence. Hence, this study provides new insight into the transcriptomic profile underlying pathogenicity and virulence differentiation of Foc.
Project description:Many bacteria have developed strategies for metamorphosis into sophisticated survival forms to survive extended periods of environmental stress. As a global causative agent of vibriosis in marine fish farming, Vibrio anguillarum (V. anguillarum) can efficiently grow and proliferate under environmental stress, but the specific mechanism is not clear. In the present study, survival, virulent characteristics, and transcriptomic analysis of the V. anguillarum BH1 were performed under starvation stress. The results demonstrated that V. anguillarum was still culturable and showed rippled surface after 6 months of starvation. Starved cells maintained their infectivity in half-smooth tongue sole (Cynoglossus semilaevi). Detection of virulence factors and virulence-associated genes in starved cells showed that the starved strain still produced ?-hemolysis on rabbit blood agar, caseinase, dnase, and gelatinase, and possessed empA, vah1, vah2, vah3, vah4, vah5, rtxA, flaA, flaD, flaE, virC, tonB, mreB, toxR, rpoS, and ftsZ virulence-related genes. In addition, we first reported the RNA-seq study for V. anguillarum with and without starvation treatment for a period of 6 months and emphasized the regulation of gene expression at the whole transcriptional level. It indicated that V. anguillarum expressed 3,089 and 3,072 genes in the control group and starvation stress group, respectively. The differently expressed genes (DEGs) of the starved strain were thereby identified, including 251 up-regulated genes and 272 down-regulated genes in comparison with the non-starved strain. Gene Ontology (GO) analysis and Kyto Encyclopedia Genes and Genomes (KEGG) enrichment analysis of DEGs were also analyzed. GO functional classification revealed that among the significantly regulated genes with known function categories, more genes affiliated with signal transducer activity, molecular transducer activity, and cell communication were significantly up-regulated, and more genes affiliated with cellular macromolecule, cellular component, and structural molecule activity were significantly down-regulated. In addition, the DEGs involved in the pathway of two-component system was significantly up-regulated, and the pathways of ribosome and flagellar assembly were significantly down-regulated. This study provides valuable insight into the survival strategies of V. anguillarum and suggests that a portion of the bacterial populations may remain pathogenic while persisting under starvation stress by up-regulating or down-regulating a series of genes.
Project description:Citrus canker caused by Xanthomonas citri subsp. citri is one of the most important bacterial diseases of citrus, impacting both plant growth and fruit quality. Identifying and elucidating the roles of genes associated with pathogenesis has aided our understanding of the molecular basis of citrus-bacteria interactions. However, the complex virulence mechanisms of X. citri subsp. citri are still not well understood. In this study, we characterized the role of PhoP in X. citri subsp. citri using a phoP deletion mutant, ΔphoP. Compared with wild-type strain XHG3, ΔphoP showed reduced motility, biofilm formation, as well as decreased production of cellulase, amylase, and polygalacturonase. In addition, the virulence of ΔphoP on citrus leaves was significantly decreased. To further understand the virulence mechanisms of X. citri subsp. citri, high-throughput RNA sequencing technology (RNA-Seq) was used to compare the transcriptomes of the wild-type and mutant strains. Analysis revealed 1017 differentially-expressed genes (DEGs), of which 614 were up-regulated and 403 were down-regulated in ΔphoP. Gene ontology functional enrichment and Kyoto Encyclopedia of Genes and Genomes pathway analyses suggested that the DEGs were enriched in flagellar assembly, two-component systems, histidine metabolism, bacterial chemotaxis, ABC transporters, and bacterial secretion systems. Our results showed that PhoP activates the expression of a large set of virulence genes, including 22 type III secretion system genes and 15 type III secretion system effector genes, as well as several genes involved in chemotaxis, and flagellar and histidine biosynthesis. Two-step reverse-transcription polymerase chain reaction analysis targeting 17 genes was used to validate the RNA-seq data, and confirmed that the expression of all 17 genes, except for that of virB1, decreased significantly. Our results suggest that PhoP interacts with a global signaling network to co-ordinate the expression of multiple virulence factors involved in modification and adaption to the host environment during infection.
Project description:Many virulence genes in plant bacterial pathogens are coordinately regulated by "global" regulatory genes. Conducting DNA microarray analysis of bacterial mutants of such genes, compared with the wild type, can help to refine the list of genes that may contribute to virulence in bacterial pathogens. The regulatory gene algU, with roles in stress response and regulation of the biosynthesis of the exopolysaccharide alginate in Pseudomonas aeruginosa and many other bacteria, has been extensively studied. The role of algU in Xylella fastidiosa, the cause of Pierce's disease of grapevines, was analyzed by mutation and whole-genome microarray analysis to define its involvement in aggregation, biofilm formation, and virulence. In this study, an algU::nptII mutant had reduced cell-cell aggregation, attachment, and biofilm formation and lower virulence in grapevines. Microarray analysis showed that 42 genes had significantly lower expression in the algU::nptII mutant than in the wild type. Among these are several genes that could contribute to cell aggregation and biofilm formation, as well as other physiological processes such as virulence, competition, and survival.
Project description:Tobacco brown spot, caused by Alternaria species, is a devastating tobacco disease. To explore the role of a group III histidine kinase (AlHK1) on A. longipes pathogenesis, the invasion progress of A. longipes was monitored. We found that the wild-type strain C-00 invaded faster than the AlHK1-disrupted strain HK?4 in the early and middle infection stages and the reverse trend occurred in the late infection stage. Then, eight invasion transcriptomes were performed using RNA-Seq and 205 shared, 505 C-00 and 222 HK?4 specific differentially expressed genes (DEGs) were identified. The annotation results showed seven antioxidant activity genes were specifically identified in the HK?4 DEGs. A subsequent experiment confirmed that HK?4 was more resistant to low concentrations oxidative stress than C-00. In addition, the results from 1) statistics for the number of DEGs, GO enriched terms, DEGs in clusters with rising trends, and 2) analyses of the expression patterns of some DEGs relevant for osmoadaptation and virulence showed that changes in C-00 infection existed mainly in the early and middle stages, while HK?4 infection arose mainly in the late stage. Our results reveal firstly the pathogenesis of A. longipes regulated by AlHK1 and provide useful insights into the fungal-plant interactions.
Project description:Soil alkalinity is a major abiotic constraint to crop productivity and quality. Wild soybean (Glycine soja) is considered to be more stress-tolerant than cultivated soybean (G. max), and has considerable genetic variation for increasing alkalinity tolerance of soybean. In this study, we analyzed the transcriptome profile in the roots of an alkalinity tolerant wild soybean variety N24852 at 12 and 24 h after 90 mM NaHCO3 stress by RNA-sequencing. Compared with the controls, a total of 449 differentially expressed genes (DEGs) were identified, including 95 and 140 up-regulated genes, and 108 and 135 down-regulated genes at 12 and 24 h after NaHCO3 treatment, respectively. Quantitative RT-PCR analysis of 14 DEGs showed a high consistency with their expression profiles by RNA-sequencing. Gene Ontology (GO) terms related to transcription factors and transporters were significantly enriched in the up-regulated genes at 12 and 24 h after NaHCO3 stress, respectively. Nuclear factor Y subunit A transcription factors were enriched at 12 h after NaHCO3 stress, and high percentages of basic helix-loop-helix, ethylene-responsive factor, Trihelix, and zinc finger (C2H2, C3H) transcription factors were found at both 12 and 24 h after NaHCO3 stress. Genes related to ion transporters such as ABC transporter, aluminum activated malate transporter, glutamate receptor, nitrate transporter/proton dependent oligopeptide family, and S-type anion channel were enriched in up-regulated DEGs at 24 h after NaHCO3 treatment, implying their roles in maintaining ion homeostasis in soybean roots under alkalinity. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis showed "phenylpropanoid biosynthesis" and "phenylalanine metabolism" pathways might participate in soybean response to alkalinity. This study provides a foundation to further investigate the functions of NaHCO3 stress-responsive genes and the molecular basis of soybean tolerance to alkalinity.
Project description:The molecular basis behind shade tolerance in plants is not fully understood. Previously, we have shown that a connection may exist between shade tolerance and dwarfism, however, the mechanism connecting these phenotypes is not well understood. In order to clarify this connection, we analyzed the transcriptome of a previously identified shade-tolerant mutant of perennial ryegrass (Lolium perenne L.) called shadow-1. shadow-1 mutant plants are dwarf, and are significantly tolerant to shade in a number of environments compared to wild-type controls. In this study, we treated shadow-1 and wild-type plants with 95% shade for 2 weeks and compared the transcriptomes of these shade-treated individuals with both genotypes exposed to full light. We identified 2,200 differentially expressed genes (DEGs) (1,096 up-regulated and 1,104 down-regulated) in shadow-1 mutants, compared to wild type, following exposure to shade stress. Of these DEGs, 329 were unique to shadow-1 plants kept under shade and were not found in any other comparisons that we made. We found 2,245 DEGs (1,153 up-regulated and 1,092 down-regulated) in shadow-1 plants, compared to wild-type, under light, with 485 DEGs unique to shadow-1 plants under light. We examined the expression of gibberellin (GA) biosynthesis genes and found that they were down-regulated in shadow-1 plants compared to wild type, notably gibberellin 20 oxidase (GA20ox), which was down-regulated to 3.3% (96.7% reduction) of the wild-type expression level under shade conditions. One GA response gene, lipid transfer protein 3 (LTP3), was also down-regulated to 41.5% in shadow-1 plants under shade conditions when compared to the expression level in the wild type. These data provide valuable insight into a role that GA plays in dwarfism and shade tolerance, as exemplified by shadow-1 plants, and could serve as a guide for plant breeders interested in developing new cultivars with either of these traits.
Project description:In our previous study, drought-resistant transgenic plants of Salvia miltiorrhiza were produced via overexpression of the transcription factor AtDREB1A. To unravel the molecular mechanisms underpinning elevated drought tolerance in transgenic plants, in the present study we compared the global transcriptional profiles of wild-type (WT) and AtDREB1A-expressing transgenic plants using RNA-sequencing (RNA-seq). Using cluster analysis, we identified 3904 differentially expressed genes (DEGs). Compared with WT plants, 423 unigenes were up-regulated in pRD29A::AtDREB1A-31 before drought treatment, while 936 were down-regulated and 1580 and 1313 unigenes were up- and down-regulated after six days of drought. COG analysis revealed that the 'signal transduction mechanisms' category was highly enriched among these DEGs both before and after drought stress. Based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation, DEGs associated with "ribosome", "plant hormone signal transduction", photosynthesis", "plant-pathogen interaction", "glycolysis/gluconeogenesis" and "carbon fixation" are hypothesized to perform major functions in drought resistance in AtDREB1A-expressing transgenic plants. Furthermore, the number of DEGs associated with different transcription factors increased significantly after drought stress, especially the AP2/ERF, bZIP and MYB protein families. Taken together, this study substantially expands the transcriptomic information for S. miltiorrhiza and provides valuable clues for elucidating the mechanism of AtDREB1A-mediated drought tolerance in transgenic plants.