Type IV secretion system is not involved in infection process in citrus.
Xanthomonas citri subsp. citri (Xcc) is a Gram-negative plant pathogenic bacteria that causes severe disease in many economically important citrus plants . The citrus canker induced by Xcc is a destructive disease characterized by canker lesions on leaves, stems, and fruits; furthermore the pathogen induces defoliation, which results in reduced yield and premature fruit drop . Control is difficult in areas where the disease is already established, and plant eradication is the only effective way to control and prevent the disease spread. Recurrent and severe attacks of the pathogen are responsible for serious economic losses in citrus groves around the world .
The focus of the present study is aimed at understanding the role of bacterial secretory systems, specifically the type IV secretory system (T4SS). Seven secretory systems are known and described in prokaryotic organisms, and each one is related to a physiological process [3-5]. Of these, the best studied is the type III secretory system (T3SS), which enables bacterial pathogens to deliver effector proteins into eukaryotic cells . Some bacterial pathogens, including species from Chlamydia, Xanthomonas, Pseudomonas, Ralstonia, Shigella, Salmonella, Escherichia, and Yersinia, depend on the T3SS to induce damage to the host. In contrast, other organisms including Agrobacterium tumefaciens, Helicobacter pylori, and Legionella pneumophila depend on the type IV secretory system (T4SS) for virulence induction .
The T3SS contains at least twenty distinct proteins, which are subdivided into three parts. The basal body of the system [8-11] is associated with an ATPase and likely facilitates the entry of substrates into the secretion apparatus . Thisbasal body is also associated with a protein needle (the second part of the T3SS), which binds the bacterium to host cells and acts as a conduit for effectors secretion. The third part of the T3SS is composed of three proteins that are exported through the bacterial needle and form a pore on the surface of the host cell, which facilitates the export of toxins into the target cytoplasm .
On the other hand, the T4SS is a multiprotein complex that consists of a protein channel (encoded by virB and virD) through which proteins or protein-DNA complexes can be translocated between bacteria (cell-to-cell communication) and into host cells . Translocation is driven by a number of cytoplasmic ATPases that potentially energize large conformational changes in the translocation complex . There are three functional types of T4SS. The first type, found in many Gram-positive and Gram-negative bacteria and some Archaea, functions in conjugation and in the transfer of TDNA into plant cells by A. tumefaciens. A second type of T4SS mediates DNA uptake in the transformation process (found in H. pylori). A third type of T4SS is used to transfer toxic effector proteins or protein complexes into the cytoplasm of host cells (found in Bordetella pertussis, Legionella pneumophila, Pseudomonas aeruginosa, and Xcc) 15].
Substrates transported by the T4SS modulate various cellular processes including apoptosis, vesicular traffic, and ubiquitination; furthermore, the number of type IV effector proteins continues to increase [16-19]. However, most of these substrates have not been functionally characterized, and their role in bacterial pathogenesis remains unknown .
In many bacteria, these two secretory systems types are well characterized; however, in Xanthomonas spp. only the T3SS has been intensively studied , in contrast to the limited number of studies involving the T4SS [21, 22]. In Xcc the T4SS deserves more attention, especially since the genome contains two copies of this system (chromosomal and plasmid-borne) . The plasmid copy is homologous to others Xanthomonads that contain the T4SS on extrachromosomal DNA. However, only Xcc and Xanthomonas campestris contain the chromosomal copy of the T4SS.
To understand the conditions that stimulate expression of T4SS genes in Xcc we used qPCR to analyze the in vitro and in planta expression of 18 ORFs from the T4SS (both chromosomal and plasmid copies) and 7 hypothetical ORFs flanking the T4SS. To validate the qPCR data, we compared expression of 29 ORFs from the T3SS, which are known to be expressed in planta.
Our results showed that the T4SS is not induced during the infection process in Xcc, but may be very important in cell-to-cell communication.
2. Materials and Methods
2.1. Microbiological Procedures. Xcc strain 306 was previously sequenced by da Silva et al. . Xcc was maintained in sterile tap water and grown on nutrient agar (NA) medium containing 3 g beef extract, 5 g peptone, and 15 g agar in 1L of distilled water at 28[degrees]C. After 24 h, three single colonies were transferred to new NA plates and incubated for 12 h at 28[degrees]C. These Xcc solid cultures were used as pre-inoculum for in planta and in vitro studies. For in planta studies, preinoculum cultures were aseptically transferred to sterile flasks containing 50 mL of nutrient broth (NB) and the bacterial concentration was adjusted to 108 CFU/mL ([OD.sub.600] = 0.3). This bacterial suspension was taken up in a 1 mL needleless syringe and used to infiltrate orange leaves (Citrus sinensis cv. pera) grown in 20 L capacity pots. A total of nine plants were inoculated (20 leaves per plant) and maintained for 72 h in a growth room at 28[degrees]C, with a 12 h photoperiod and light intensity ~2,000 lux. Three plants were used for each incubation period. After multiplication, inoculated leaves were collected, sliced into thin strips with a razor blade, and placed in a beakers with sterile distilled water in an ice bath with gentle agitation. Samples from each plant were placed in separate beakers for bacterial exudation. After 5 min, leaf debris was removed by filtration through gauze, and bacterial cells were recovered by centrifugation at 5,000 xg for 5 min at 4[degrees]C. Total RNA was extracted immediately, as described below. For in vitro studies, 1 mL of each Xcc suspension at [10.sup.8] CFU/mL were aseptically transferred to three Erlenmeyer flasks and incubated for 12 h at 28[degrees]C with shaking (200 rpm). After incubation, bacterial cells were harvested by centrifugation at 5,000 xg for 5 min. Total RNA was extracted as described below. Thus, we obtained three independent biological replicates for Xcc growth in vitro and in planta. All cultivation media were obtained from Difco Chemical Co., Detroit, USA. For confirmatory RT-qPCR, the same procedures were followed except the plant incubation period was only 72 h, due to RNA quality and concentration sufficient to yield reliable results. The time point 72 hours was the shortest period to allow obtaining satisfactory bacterial mass to the proposed analyzes involving gene expression. The bacterial cells concentration in short time (12 or 24 hours) don't allows this study. For this reason, some works are using culture media that mimic vegetable conditions to investigate the infectious process under these time scales [24, 25].
2.2. Extraction of RNA from Xcc. Each inoculated flask represented one independent biological replicate. RNA was extracted using an Illustra-RNAspin Mini RNA Isolation Kit (Amersham Biosciences) following the manufacturer's instructions. To ensure that samples did not contain DNA, PCR was performed using RNA samples treated with DNase I as a template. PCR conditions consisted of an initial denaturing step of 94[degrees]C for 3 min, followed by 35 cycles of a denaturation at 94[degrees]C for 30 s, annealing at 60[degrees]C for 30 s, and elongation at 72[degrees]C for 2 min. A final elongation step of 72[degrees] C for 4 min was performed, and then samples were maintained at 4[degrees]C until needed. The amplification reaction was conducted in a total volume of 25 [micro]L containing 200 ng RNA in 2.5 [micro]L, PCR buffer (2.5 [micro]L, Invitrogen), 1.5 mM Mg[Cl.sub.2], 0.2 mM dNTP, 300 nM 16S rRNA primer , and 1U Taq DNA polymerase (Invitrogen). The products were electrophoresed in a 1% agarose gel with TAE buffer, stained with ethidium bromide, and visualized using a UV transilluminator. No products were observed (data not shown). To verify the quality of extracted RNA, the samples were analyzed by electrophoresis in a 1% agarose gel using TAE buffer followed by ethidium bromide staining. The A260/280 ratio of RNA samples was measured, and RNA was quantified using a NanoDrop ND-1000 spectrophotometer (NanoDrop Technologies, Wilmington, DE, USA). RNA samples were stored at -80[degrees]C until needed.
2.3. Gene Expression Using RT-qPCR. First strand cDNA synthesis and all RT-qPCR reactions were done using the SuperScript III First-Strand Synthesis SuperMix for RT-qPCR (Invitrogen) as recommended by the manufacturer's specifications except for the amount of cDNA in each reaction, which was 20 ng. All PCR was performed with SYBR Green on a 7500 Real-Time PCR instrument (Applied Biosystems) using three biological replicates and three technical replicates (one for each biological replicate). PCR was for 2 min at 50[degrees]C, 10 min at 95[degrees]C, followed by 40 cycles of 15 s at 95[degrees]C, and 1 min at 60[degrees]C. To determine PCR efficiency, standard curves were generated using cDNA samples at five dilutions and measured in triplicate. rpoB, atpD, and gyrB were used as reference genes in all experiments . To perform relative expression analysis, we used the [2.sup.-[DELTA][DELTA]] CT method . Primer features are presented in Table 1.
3. Results and Discussion
3.1. qPCR Results for the T3SS. The results obtained from Xcc growing in planta or in vitro are presented in Figure 1. From the 29 T3SS genes analyzed by qPCR, only hrpA was downregulated at 72 h after inoculation (Figure 1(b)). hpa1, hpaB, hrpD6, hrpE, and hrpF showed the highest rates of expression, whereas phaE, hrpG, hrpX, and hrcA showed the lowest levels of expression. Interestingly, hrpB4 and hrpXct, which were shown to be necessary for Xcc pathogenesis , were not among the most upregulated genes in this study.
3.2. qPCR Results for the T4SS. The results for the expression levels of T4SS genes in planta and in vitro are shown in Figure 2. All genes associated with the T4SS were downregulated on Citrus leaves 72 h after inoculation (Figure 2(c)). We also analyzed the expression of hypothetical genes located near virB in chromosomal DNA (XAC2606, XAC2611, XAC2613, and XAC2622) and in plasmid pXAC64 (XACb0035, XACb0042, XACb0043, XACb0048, andXACb0049) (Figure 2(d) and Table 1). ORFs representing hypothetical genes in both the chromosome and plasmid were down-regulated when Xcc was cultivated in Citrus sinensis for 72 h. An exception was XAC2611, where expression was similar when Xcc was cultivated in culture medium or in planta (Figure 2(d)).
Our results clearly show different gene expression profiles for the T3SS and T4SS in Xcc during Citrus infection. The T4SS was previously described in A. tumefaciens, where it mediates the transfer of DNA and protein substrates to plants and other organisms via a cell contact-dependent mechanism . In Xcc, the genome sequence revealed the presence of two virB operons, one on the chromosome and a second copy in the 64 kb plasmid pXAC64 . The chromosomal genes virB1, virB3, virB4, virB8, virB9, and virB11 and the plasmid-encoded genes virB1, virB2, virB4, virB6, virB9, and virB11 were all down-regulated in planta (Figure 2(c)). This was somewhat surprising because the T4SS is essential for a successful infection in many Gram-negative pathogenic bacteria . The fact that ORFs representing hypothetical genes in both the chromosome and plasmid near the virB genes were also down-regulated under the same condition (Figure 2(d)) indicates that they could be related to the T4SS system in Xcc. Recent studies in Brucella suis  and in A. tumefaciens  showed that alterations in VirB8 result in protein dimerization, a process that modifies the T4SS structure and affects bacterial virulence. In Streptococcus suis , the knockout of the virD4-89K and virB4-89K of the T4SS eliminated the lethality of a highly virulent strain and impaired its ability to trigger host immune responses in mice. Recent studies continue to demonstrate the importance of the T4SS and its components in virulence; thus the lack of induction of Xcc T4SS genes in the present study is intriguing. However, in Xanthomonas campestris pv. campestris T4SS deletion mutant displayed the same virulence as wild type and authors conclude that T4SS is not involved in pathogenicity in that Xanthomonas .
Wang et al.  presented evidence that in planta transfer of a 37 kb plasmid (pXcB) from Xanthomonas aurantifolii to Xanthomonas citri can occur via T4SS. Thus, at least the T4SS copy present in Xcc plasmid can play a hole in horizontal gene transfer.
All but one of the twenty-nine genes from the T3SS of Xcc were up-regulated in planta. Laia et al.  showed that Xcc mutants containing mutations in hrpB4 or hrpXct failed to cause disease and growth in citrus leaves was lower than the wild-type Xcc strain 306. These two genes, which are not among the most up-regulated genes in the present study, are part of the hrp (hypersensitive reaction and pathogenicity) system and comprise part of the T3SS . In the related pathogen, Xanthomonas campestris pv. vesicatoria (Xcv), a hrpB4 mutant was unable to cause disease in susceptible pepper plants or the hypersensitive reaction in pepper plants carrying the respective compatible R gene . Previously, hrpXv was shown to be necessary for transcriptional activation of five hrp genes (loci hrpB to hrpF) 37], and hrpB4 was required for complete functionality of the T3SS in Xcv . Thus it is apparent that a gene does not have to be strongly up-regulated during infection to play an important role in virulence. Multiple genes, including hpaA, hpaE, hpaF, hpaP, hrpB, hrpB1, hrpB2, hrpB7, hrpD5, hrpM, hrpW, hrcC, hrcQ, hrcS, hrcT, and hrcV, were expressed at levels similar to hrpXct and hrpB4 and are good candidates for further studies into their roles in citrus canker disease.
Among the most up-regulated genes, hrpD6 warrants further attention. A hrpD6 mutant of Xanthomonas oryzae pv. oryzae (Xoo) failed to trigger a hypersensitive response in tobacco and was nonpathogenic in rice because the mutation in hrpD6 impacts the secretion of T3SS effectors, such as Hpa1, which is translocated through the T3SS .
Our qPCR data showed that hpal was the most up-regulated gene during Citrus sinensis infection by Xcc, followed by hrpD6 (Figure 1(b)). Conversely, hrpA, which encodes an important component of the T3SS pilus , was downregulated in our study. Previously, hrpA mutants of Pseudomonas syringae pv. tomato DC3000 showed reduced accumulation of structural components of the hrp pilus . Haapalainen et al.  showed that soluble plant cell signals induce the expression of hrp/hrc genes and specifically upregulate hrpA. Interestingly, they found that HrpA does not accumulate to high levels intracellularly, suggesting that some kind of feedback regulation takes place between secretion and production of HrpA, perhaps through degradation of intracellular HrpA. Our work shows that this may also be applicable to hrpA gene in Xcc: its mRNA may be degraded faster, just as happen with HrpA in Pseudomonas syringae.
Our finds confirm that the T3SS genes are induced in the successful infection of Citrus sinensis by Xcc, and therefore are excellent targets to help control or decrease the severity of citrus canker, whereas T4SS seems not have any relation with virulence. On the other hand, our results show that T4SS is not induced under the same infection conditions, which could indicate that it is not necessary for infection but only for cell-to-cell communication.
Conflict of Interests
The authors declare that there is no conflict of interests regarding the publication of this paper.
This work was supported by grants from Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), Fundo de Defesa da Citricultura (FUNDECITRUS), Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES), and Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) for the biological tests and fellowship Grants, and by Grants from Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (CBB-APQ-04425-10) for Xcc functional database creation. The funding agencies had no role in study design, data collection and analysis, decision to publish, or preparation of the paper.
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Tiago Rinaldi Jacob, (1) Marcelo Luiz de Laia, (2) Leandro Marcio Moreira, (3) Janaina Fernandes Goncalves, (2) Flavia Maria de Souza Carvalho, (4) Maria Ines Tiraboschi Ferro, (1) and Jesus Aparecido Ferro (1)
(1) Faculdade de Ciencias Agrarias e Veterinarias de Jaboticabal, Departamento de Tecnologia, Universidade Estadual Paulista (UNESP), 14.884-900 Jaboticabal, SP, Brazil
(2) Departamento de Engenharia Florestal, Faculdade de Ciencias Agrarias, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 39.100-000 Diamantina, MG, Brazil
(3) Departamento de Ciencias Biologicas (DECBI), Instituto de Ciencias Exatas e Biologicas (ICEB) and Nucleo de Pesquisas em Ciencias Biologicas (NUPEB), Universidade Federal de Ouro Preto, 35.400-000 Ouro Preto, MG, Brazil
(4) Embrapa Informatica Agropecuaria, CNPTIA-EMBRAPA, Campinas, SP, Brazil
Correspondence should be addressed to Jesus Aparecido Ferro; firstname.lastname@example.org
Received 17 August 2013; Accepted 10 January 2014; Published 23 February 2014
Academic Editor: Joseph Falkinham
Table 1: General features of the T3SS and T4SS primer sequences. XACID Gene Gene ID Product (NCBI Annotation) XAC0293 hrpB 1154364 ATP-dependent RNA helicase XAC0393 hpaF 1154464 HpaF protein XAC0394 hrpF 1154465 HrpF protein XAC0396 hpaB 1154467 HpaB protein XAC0397 hrpE 1154468 HrpE protein XAC0398 hrpD6 1154469 HrpD6 protein XAC0399 hrpD5 1154470 HrpD5 protein XAC0400 hpaA 1154471 HpaA protein XAC0401 hrcS 1154472 HrcS protein XAC0402 hrcR 1154473 Protein T3SS XAC0403 hrcQ 1154474 HrcQ protein XAC0404 hpaP 1154475 HpaP protein XAC0405 hrcV 1154476 HrcV protein XAC0406 hrcU 1154477 HrcU protein T3SS XAC0407 hrpBl 1154478 HrpBl protein XAC0408 hrpB2 1154479 HrpB2 protein XAC0409 hrc] 1154480 HrcJ protein XAC0410 hrpB4 1154481 HrpB4 protein XAC0411 hrpB5 1154482 Protein T3SS HrpB XAC0412 hrcN 1154483 T3SS ATPase protein XAC0413 hrpB7 1154484 HrpB7 protein XAC0414 hrcT 1154485 HrcT protein XAC0415 hrcC 1154486 HrcC protein XAC0416 hpal 1154487 Hpal protein monovalent XAC0459 phaE 1154530 cation/H + antiporter subunit E XAC0618 hrpM 1154689 Glucosyltransferase MdoH XAC1265 hrpG 1155336 HrpG protein XAC1266 hrpXct 1155337 HrpX protein Heat-inducible XAC1520 hrcA 1155591 transcriptional XAC1994 hrpX 1156064 repressor HrpX-like protein XAC2047 phaE 1156118 PHA synthase subunit XAC2606 -- 1156677 Hypothetical protein XAC2611 -- 1156682 Hypothetical protein XAC2612 virB6 1156683 VirB6 protein XAC2613 -- 1156684 Hypothetical protein XAC2614 virB4 1156685 VirB4 protein XAC2615 virB3 1156686 VirB3 protein XAC2616 virB2 1156687 VirB2 protein XAC2617 virBl 1156688 VirBl protein XAC2618 virBll 1156689 VirBll protein XAC2619 virBlO 1156690 VirBlO protein XAC2620 virB9 1156691 VirB9 protein XAC2621 virB8 1156692 VirB8 protein XAC2622 -- 1156693 Hypothetical protein XAC2623 virD4 1156694 VirD4 protein XAC2922 hrpW 1156993 HrpW protein XAC3122 hrpA 1157193 ATP-dependent RNA helicase XACb0035 -- 1158522 Hypothetical protein XACb0036 virBl 1158523 VirBl protein XACb0037 virBll 1158524 VirBll protein XACb0038 virBlO 1158525 VirBlO protein XACb0039 virB9 1158526 VirB9 protein XACb0040 virB8 1158527 VirB8 protein XACb0041 virB6 1158528 VirB6 protein XACb0042 -- 1158529 Hypothetical protein XACID Gene Gene ID Product (NCBI Annotation) XACb0043 -- 1158530 Hypothetical protein XACb0044 virB5 1158531 VirB5 protein XACb0045 virB4 1158532 VirB4 protein XACb0046 virB3 1158533 VirB3 protein XACb0047 virB2 1158534 VirB2 protein XACb0048 -- 1158535 Hypothetical protein XACb0049 -- 1158536 Hypothetical protein XACID Primers (Forward) Primers (Reverse) XAC0293 GCCGTATCCCGTTGACCTT ACCGCCCCTTCATCTCTTTT XAC0393 GGCGAGCGTTTTGACAA CCGGAGATCCTGGCAGTTT XAC0394 GCCGCGACGCAGTTG CGGTGATCGAGTTGTTCAA XAC0396 GTCCGTGTACGCGCAAGAC TGACGCCGGCATCATTG XAC0397 ACGAGGCCCAGAAGTCCAT CCACGTT GAAGTCCAGATCATTT XAC0398 ACCGATACGGTCACCCAAGA GATCCGCCGCCTTGGT XAC0399 GCCCTGAAGTGCGTTCGTTA TCACGGACGGGTCTTGCT XAC0400 CGCCACCCCAACAGAAAA ACGGCATCAGCTCCATCAA XAC0401 CG ACGAT CTAGTGCG ATTTACCT CGACCACCGGCAAGGA XAC0402 ACACGGGAACGCGAAAAA CCTTGGGCCAGATCTGTTGT XAC0403 GCAGCTGGAAGTGGACCAA GGCTGCAAACCCGACAAC XAC0404 TGTCGATGGCACGAAATACC CCCAACCGCGCCATT XAC0405 GCCGCAAGTTGGTCGAGTT CTCTGCCATATCGCGATTCC XAC0406 AGCCGCGGTGCTCTTTG TAGTCGCCGGCCGATTT XAC0407 CTGCGGCCAGAGCTGAAG ACCGCGCTTGATGGAAATC XAC0408 CAGCGCAGCAGATCAAGTTG CGCCGACGCTGACATTG XAC0409 GAGCGGCACGCCAATC TGT CGAGATCAAGCCATCCTT XAC0410 GGACAACACGCGGATCGA GTCCGTCCAGCGCTGAA XAC0411 CGCACGCCTGGGATATG AGGCCGGATTCGTTCCA XAC0412 TCGATGGGCACCTGATTCTC CGTCGATTGCCGGGTACT XAC0413 CCGCGCTGATGGACAAG GCTGCAGGATCGTGTCGATA XAC0414 ATCCAGCAATCCGACAGCAT CACCGGTGCGGACAGTTT XAC0415 CAGATGCGGCTGGATGTG CCGTCCACGGTGTTGGAT XAC0416 GCAGCAGGCCGGTCAGT TT CAT CAGCAT CTGGGT GTATT G XAC0459 CCATCCCGGCTTCATCTG GCGATGCCGTGAATGTTG XAC0618 CAAGGGCCTGCACTGGAT GCATCAACAGACCCCACATC XAC1265 CGGCAAGCCGATCGTATT GAAAAGAGCAGCCAGGCAAT XAC1266 GCCTACAGCTACAT GAT CACCAAT TGCGGCCACTTCGTTGA XAC1520 AGTTCGCGTTTCGGCATATC CGGTTCTGCACCTCGTTGT XAC1994 CTGGTCTGATGCGAGCTTTCT GCGTACTCGTCCACGATCAA XAC2047 AGCAGGGTGCATCGAAGAAG TTTTCGGAGCCGCCTTTT XAC2606 CCCTCAGTGTGGGCCAGAT AGGAGGCGGTTGAGGGATA XAC2611 GGGAGCCCGCAATGTG GGAGGCGTGGGAATATCATCT XAC2612 TGCAGCAGGGAGGATTAGGA CGGCGGTGCGGTGAT XAC2613 CGAAGGGAGATGGAAGCAGTT GCTCAACAGATCGGCTGGAA XAC2614 GACGTCGCTTGGTGGAGAAA TTCCTCGGCGCGAATCT XAC2615 GCCCCGCCATGTTTTTG CGCCCGCACCAATGAA XAC2616 TCGCCGATGCCAAAATG CAGCAACG AAAT GAATAGCAAT G XAC2617 CGTATCGAGTCGTCGCGTAAT CACCAGGCGTCCACCAA XAC2618 CGCTGGT CAACCACATT CC CCTGGCGTCCTCAATCGT XAC2619 CCATTGCAGCTCTCTTGATTCTC GAATCCTCCCCGCTTTGC XAC2620 GCT GAGCCCGAACGAAAAA GCT CCCAT CCACCAGT GAA XAC2621 TCGTCATGGCAGATGCGTAT CCGAAGTTGGGCTCAAGCT XAC2622 GGCGGATTCCAATATGCAGTT TGGCCCGATCAAGGTGTAG XAC2623 TCGCTGGAATCCATTGACCTA TCAAATCCGAAACGCGAAAT XAC2922 GGCGGACACACCGACATC TGCCTTTCAGGGTGGAGTCTT XAC3122 TGCGCGCTCTGAATTCG GGACTGGGTAAGATCTTCATGCA XACb0035 CGAGACGAGAACGGCCATT TGTCACGCAGCAATTCGAA XACb0036 CGTTACAACCTCGCCAAATATG CTGCCCGCCTTGAGATTG XACb0037 CCCGGAAGCGGTTGAGT CGTGAGCGACCCCTTGTG XACb0038 TCTACGTGAACAAAGACCTCGATT CGCTTGGCTCCGTCGAT XACb0039 GCTCACGCGGCGAAGTT GCACTTGCTTGACACGATCATC XACb0040 CTCGAACAAGCTCAAACAGGAA AACAGCAGCAACCCGATGA XACb0041 GCGCAGCTCGTCATCGT CGCGGACACCCAACATG XACb0042 CCGGGAACCCGCTTTTA GGAAGCCACTGCCGAAACT XACID Primers (Forward) Primers (Reverse) XACb0043 TTCGCGGCCCTCATCTC AGGGCGACTTGTTGAACTTGTT XACb0044 CAGGCCGCCTACGAGAAG GGGATTGGCGAACAGGTCTT XACb0045 GGAACAGGCAAAAGACGTCAAC CCCGACAAGGTTTGAACGA XACb0046 TCTTGCGATGAGCTTTTATTTCC CCCAAAGT GAT CGCGTGATT XACb0047 CGATCTGGCGGCTAACGT ATGCGAGCTGCGGAAGAA XACb0048 GGCGGATGACGTTGAAGCT CGCGGTAACGACCTCATAAAC XACb0049 ACCACGGATCCTGGCAAAT AGCAGCCCCCGTGAACA XACID Amplicon System (bp) XAC0293 81 T3SS XAC0393 57 T3SS XAC0394 62 T3SS XAC0396 53 T3SS XAC0397 66 T3SS XAC0398 55 T3SS XAC0399 54 T3SS XAC0400 59 T3SS XAC0401 68 T3SS XAC0402 58 T3SS XAC0403 57 T3SS XAC0404 58 T3SS XAC0405 58 T3SS XAC0406 51 T3SS XAC0407 60 T3SS XAC0408 69 T3SS XAC0409 54 T3SS XAC0410 52 T3SS XAC0411 63 T3SS XAC0412 63 T3SS XAC0413 60 T3SS XAC0414 54 T3SS XAC0415 59 T3SS XAC0416 57 T3SS XAC0459 54 T3SS XAC0618 86 T3SS XAC1265 54 T3SS XAC1266 63 T3SS XAC1520 91 T3SS XAC1994 90 T3SS XAC2047 63 T3SS XAC2606 58 H_T4SS_C XAC2611 59 H_T4SS_C XAC2612 56 T4SS_C XAC2613 59 H_T4SS_C XAC2614 53 T4SS_C XAC2615 54 T4SS_C XAC2616 62 T4SS_C XAC2617 57 T4SS_C XAC2618 56 T4SS_C XAC2619 61 T4SS_C XAC2620 59 T4SS_C XAC2621 61 T4SS_C XAC2622 59 H_T4SS_C XAC2623 59 T4SS_C XAC2922 58 T3SS XAC3122 76 T3SS XACb0035 55 H_T4SS_P XACb0036 74 T4SS_P XACb0037 58 T4SS_P XACb0038 64 T4SS_P XACb0039 58 T4SS_P XACb0040 60 T4SS_P XACb0041 55 T4SS_P XACb0042 52 H_T4SS_P XACID Amplicon (bp) System XACb0043 58 H_T4SS_P XACb0044 57 T4SS_P XACb0045 57 T4SS_P XACb0046 59 T4SS_P XACb0047 56 T4SS_P XACb0048 56 H_T4SS_P XACb0049 51 H_T4SS_P This table provides primers sequences, ORFs identification ID, genes name, and respective Xanthomonas citri subsp. citri secretory systems. T4SS: type IV secretion system; T3SS: type III secretion system; C: chromosomal copy; P: plasmid copy; H: hypothetical genes associated with the T4SS.
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|Title Annotation:||Research Article|
|Author:||Jacob, Tiago Rinaldi; de Laia, Marcelo Luiz; Moreira, Leandro Marcio; Goncalves, Janaina Fernandes;|
|Publication:||International Journal of Microbiology|
|Date:||Jan 1, 2014|
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