Project description:This SuperSeries is composed of the following subset Series: GSE9640: Transcriptome Profiling of Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola on two different medias GSE9643: Transcriptome Profiling of Xanthomonas oryzae pv. oryzae knockout mutants at different hybridization conditions and PMTs Keywords: SuperSeries Refer to individual Series
Project description:Xanthomonas oryzae pv. oryzae (Xoo) and X. oryzae pv. oryzicola (Xoc) are important bacterial pathogens of the worldwide staple and grass model, rice. Xoo invades rice vascular tissue to cause bacterial leaf blight, a serious disease of rice throughout the world. Xoc colonizes the parenchyma tissue to cause bacterial leaf steak, a disease of emerging importance. We have designed oligonucleotide probes (50-70-mers) represented 2,858 Xoo genes and 1,816 Xoc genes annotated by The Institute for Genomic Research (TIGR). To validate the Xo arrays, self-hybridization samples and tests of the non-specific hybridization using randomly spotted oligonucleotides corresponding to the hygromycin phosphotransferase gene (hph), and blank spot and of the correlation coefficient between biological replicates as well as between duplicate spots revealed that the data generated from our oligo array were highly reliable and consistent. To demonstrate application of Xo array, we performed expression profiling experiments on arrays hybridized with RNA of Xoo and Xoc grown in the two different nutrient-condition media. Several sets of genes involved in bacterial movement, chemotaxis, and hrp genes differentially express in response to different treatment. Due to comprehensive views of microarray study, extended biological events of plant-bacteria interaction was described. This publicly available microarray for Xanthomonas oryzae (Xo) is an enabling resource for a large and international community of scientists to better understand not only Xo biology but also many other Xanthomonas species that cause significant losses on crops. Keywords: Media condition response
Project description:Xanthomonas oryzae pv. oryzae (Xoo) and Xanthomonas oryzae pv. oryzicola (Xoc) lead to the devastating rice bacterial diseases and have a very close genetic relationship. There are tissue-specificity differences between Xoo and Xoc, i.e., Xoo only proliferating in xylem vessels and Xoc spreading in intercellular space of mesophyll cell. But there is little known about the determinants of tissue-specificity between Xoo and Xoc. Here we show that Xoc can spread in the intercellular spaces of mesophyll cells to form streak lesions. But Xoo is restricted to growth in the intercellular spaces of mesophyll cells on the inoculation sites. In vivo, Xoc largely breaks the surface and inner structures of cell wall in mesophyll cells in comparison with Xoo. In vitro, Xoc strongly damages the cellulose filter paper in comparison with Xoo. These results suggest that the stronger cell wall-degradation ability of Xoc than that of Xoo may be directly determining the tissue-specificity.
Project description:DNA N6-methyladenine (6mA) modifications expand the information capacity of DNA and have long been known to exist in bacterial genomes. Xanthomonas oryzae pv. Oryzicola (Xoc) is the causative agent of bacterial leaf streak, an emerging and destructive disease in rice worldwide. However, the genome-wide distribution patterns and potential functions of 6mA in Xoc are largely unknown. In this study, we analyzed the levels and global distribution patterns of 6mA modification in genomic DNA of seven Xoc strains (BLS256, BLS279, CFBP2286, CFBP7331, CFBP7341, L8 and RS105). The 6mA modification was found to be widely distributed across the seven Xoc genomes, accounting for percent of 3.80, 3.10, 3.70, 4.20, 3.40, 2.10, and 3.10 of the total adenines in BLS256, BLS279, CFBP2286, CFBP7331, CFBP7341, L8, and RS105, respectively. Notably, more than 82% of 6mA sites were located within gene bodies in all seven strains. Two specific motifs for 6 mA modification, ARGT and AVCG, were prevalent in all seven strains. Comparison of putative DNA methylation motifs from the seven strains reveals that Xoc have a specific DNA methylation system. Furthermore, the 6 mA modification of rpfC dramatically decreased during Xoc infection indicates the important role for Xoc adaption to environment.
Project description:Xanthomonas oryzae pv. oryzicola (Xoc) causes bacterial leaf streak (BLS) in rice, a serious bacterial disease of rice in Asia and parts of Africa. The virulence mechanisms of Xoc are not entirely clear and control measures for BLS are poorly developed. The solo LuxR proteins are widespread and shown to be involved in virulence in some plant associated bacteria (PAB). Here, we have cloned and characterized a PAB LuxR solo from Xoc, named as XocR. Mutation of xocR almost completely impaired the virulence ability of Xoc on host rice, but did not alter the ability to trigger HR (hypersensitive response, a programmed cell death) on non-host (plant) tobacco, suggesting the diversity of function of xocR in host and non-host plants. We also provide evidence to show that xocR is involved in the regulation of growth-independent cell motility in response to a yet-to-be-identified rice signal, as mutation of xocR impaired cell swimming motility of wild-type Rs105 in the presence but not absence of rice macerate. We further found that xocR regulated the transcription of two characterized virulence-associated genes (recN and trpE) in the presence of rice macerate. The promoter regions of recN and trpE possessed a potential binding motif (an imperfect pip box-like element) of XocR, raising the possibility that XocR might directly bind the promoter regions of these two genes to regulate their transcriptional activity. Our studies add a new member of PAB LuxR solos and also provide new insights into the role of PAB LuxR solo in the virulence of Xanthomonas species.
Project description:The genus Xanthomonas comprises phytopathogenic bacteria which infect about 400 host species, including a wide variety of economically important plants. Xanthomonas oryzae pv. oryzicola (Fang et al., 1957) Swings et al., 1990 is the causal agent of bacterial leaf streak (BLS) being one of the most destructive bacterial diseases of rice. BLS symptoms are very similar to those of bacterial blight caused by closely related Xanthomonas oryzae pv. oryzae. X. o. pv. oryzae and X. o. pv. oryzicola and often occur in rice f ields simultaneously, so separate leaves may show symptoms of both diseases. The quarantine status and high severity of the pathogen require a highly eff icient, fast and precise diagnostic method. We have developed an assay for Xanthomonas oryzae pv. oryzicola detection using real-time polymerase chain reaction (qPCR) and PCR amplicon sequencing. The DNA samples of X. o. pv. oryzae and X. o. pv. oryzicola were obtained from the collection of CIRM-CFBR (France). To evaluate the analytical sensitivity of the assay, a vector construct based on the pAL2-T plasmid was created through the insertion of X. o. pv. oryzicola target fragment (290 bp). Primers and a probe for qPCR were selected for the hpa1 gene site. They allowed identifying all the strains the sequences of which had been loaded in the GenBank NCBI Nucleotide database before November 11, 2021. The SeqX.o.all sequencing primers were selected for the hrp gene cluster sequence, namely for the nucleotide sequence encoding the Hpa1 protein, the sequencing of which allows for eff icient differentiation of X. oryzae species. The analytical specif icity of the system was tested using the DNAs of 53 closely related and accompanying microorganisms and comprised 100 % with no false-positive or false-negative results registered. The system’s analytical sensitivity was not less than 25 copies per PCR reaction. Its eff icacy has been conf irmed using f ive different qPCR detection systems from different manufacturers, so it can be recommended for diagnostic and screening studies.
Project description:In this study, using a novel dual RNA-seq approach we monitored the global transcriptional changes in real time of Xanthomonas oryzae pv. oryzicola and rice during infection. Our transcriptome maps of Xoc strains infecting rice provide mechanistic insights into the bacterias adaptive responses to the host niche, with modulation of central metabolism being an important signature. The study also uncovers that infected rice responds by substantial alteration of the cell wall, stress and structural proteins.
Project description:Xanthomonas oryzae pv. oryzae, which causes rice bacterial leaf blight, and Xanthomonas oryzae pv. oryzicola, which causes rice bacterial leaf streak, are important plant-pathogenic bacteria. A member of the adaptor protein family, ankyrin protein, has been investigated largely in humans but rarely in plant-pathogenic bacteria. In this study, a novel ankyrin-like protein, AnkB, was identified in X. oryzae pv. oryzae and X. oryzae pv. oryzicola. The expression of ankB was significantly upregulated when these bacteria were treated with phenazine-1-carboxylic acid (PCA). ankB is located 58 bp downstream of the gene catB (which encodes a catalase) in both bacteria, and the gene expression of catB and catalase activity were reduced following ankB deletion in X. oryzae pv. oryzae and X. oryzae pv. oryzicola. Furthermore, we demonstrated that AnkB directly interacts with CatB by glutathione S-transferase (GST) pulldown assays. Deletion of ankB increased the sensitivity of X. oryzae pv. oryzae and X. oryzae pv. oryzicola to H2O2 and PCA, decreased bacterial biofilm formation, swimming ability, and exopolysaccharide (EPS) production, and also reduced virulence on rice. Together our results indicate that the ankyrin-like protein AnkB has important and conserved roles in antioxidant systems and pathogenicity in X. oryzae pv. oryzae and X. oryzae pv. oryzicola.IMPORTANCE This study demonstrates that the ankyrin protein AnkB directly interacts with catalase CatB in Xanthomonas oryzae pv. oryzae and Xanthomonas oryzae pv. oryzicola. Ankyrin protein AnkB can affect the gene expression of catB, catalase activity, and sensitivity to H2O2 In Xanthomonas spp., the locations of genes ankB and catB and the amino acid sequence of AnkB are highly conserved. It is suggested that in prokaryotes, AnkB plays a conserved role in the defense against oxidative stress.
Project description:Bacterial leaf streak (BLS) caused by Xanthomonas oryzae pv. oryzicola (Xoc) is one of the most important quarantine diseases in the world. Breeding disease-resistant varieties can solve the problem of prevention and treatment of BLS from the source. The discovery of the molecular mechanism of resistance is an important driving force for breeding resistant varieties. In this study, a BLS-resistant near isogenic line NIL-bls2 was used as the material. Guangxi Xoc strain gx01 (abbreviated as WT) and its mutant strain (abbreviated as MT) with a knockout type III effectors (T3Es) gene were used to infect rice material NIL-bls2. The molecular interaction mechanism of rice resist near isogenic lines in response to infection by different pathogenic strains was analyzed by transcriptome sequencing. The results showed that there were 415, 134 and 150 differentially expressed genes (DEGs) between the WT group and the MT group at 12, 24 and 48 h of post inoculation (hpi). Through GO and KEGG enrichment analysis, it was found that, compared with non-pathogenic strains, the T3Es secreted by pathogenic strains inhibited the signal transduction pathway mediated by ethylene (ET), jasmonic acid (JA) and salicylic acid (SA), and the MAPKK (MAPK kinase) and MAPKKK (MAPK kinase kinase) in the MAPK (mitogen-activated protein kinase) cascade reaction, which prevented plants from sensing extracellular stimuli in time and starting the intracellular immune defense mechanism; and inhibited the synthesis of lignin and diterpenoid phytochemicals to prevent plants from establishing their own physical barriers to resist the invasion of pathogenic bacteria. The inhibitory effect was the strongest at 12 h, and gradually weakened at 24 h and 48 h. To cope with the invasion of pathogenic bacteria, rice NIL-bls2 material can promote wound healing by promoting the synthesis of traumatic acid at 12 h; at 24 h, hydrogen peroxide was degraded by dioxygenase, which reduced and eliminated the attack of reactive oxygen species on plant membrane lipids; and at 48 h, rice NIL-bls2 material can resist the invasion of pathogenic bacteria by promoting the synthesis of lignin, disease-resistant proteins, monoterpene antibacterial substances, indole alkaloids and other substances. Through transcriptome sequencing analysis, the molecular interaction mechanism of rice resistance near isogenic lines in response to infection by different pathogenic strains was expounded, and 5 genes, Os01g0719300, Os02g0513100, Os03g0122300, Os04g0301500, and Os10g0575100 closely related to BLS, were screened. Our work provides new data resources and a theoretical basis for exploring the infection mechanism of Xoc strain gx01 and the resistance mechanism of resistance gene bls2.