scholarly journals PthAW1, a transcription activator-like effector of Xanthomonas citri subsp. citri, promotes host specific immune responses

2021 ◽  
Author(s):  
Doron Teper ◽  
Jin Xu ◽  
Sheo Shankar Pandey ◽  
Nian Wang
Keyword(s):  
Host Range ◽  
Sweet Orange ◽  
Phenotypic Traits ◽  
Ion Leakage ◽  
Sequencing Analysis ◽  
Transcription Activator ◽  
Xanthomonas Citri ◽  
Pr Genes ◽  
Canker Disease ◽  
Citrus Varieties

Citrus canker disease caused by Xanthomonas citri subsp. citri (Xcc) is one of the most destructive diseases in citrus. XccA causes canker disease in most commercial citrus varieties, whereas XccAW, which is genetically similar to XccA, infects only lime and alemow. Understanding the mechanism that determines the host range of pathogens is critical to investigating and utilizing host resistance. We hypothesized that XccAW would undergo mutations in genes that restrict its host range when artificially inoculated into incompatible citrus varieties. To test this hypothesis, we used an experimental evolution approach to identify phenotypic traits and genetic loci associated with the adaptation of XccAW to incompatible sweet orange. Repeated inoculation and re-isolation cycles improved the ability of three independent XccAW strains to colonize sweet orange. Adapted XccAW strains displayed increased expression of type III secretion system and effector genes. Genome sequencing analysis indicated that two of the adapted strains harbored mutations in pthAW1, a transcription activator-like effector (TALE) gene, that corresponded to the removal of one or two repeats from the central DNA binding repeat region. Introduction of the original but not the adapted pthAW1 variants into XccA abolished its ability to cause canker symptoms in sweet orange, Meyer lemon, and clementine but not in other XccAW-resistant citrus varieties. The original pthAW1, when expressed in XccA, induced ion leakage and the expression of PR genes, but had no effect on CsLOB1 expression of sweet orange. Our study has identified a novel host-specific avirulence TALE.

scholarly journals Modified Monosaccharides Content of Xanthan Gum Impairs Citrus Canker Disease by Affecting the Epiphytic Lifestyle of Xanthomonas citri subsp. citri

2021 ◽  
Vol 9 (6) ◽  
pp. 1176
Author(s):  
Simone Cristina Picchi ◽  
Laís Moreira Granato ◽  
Maria Júlia Festa Franzini ◽  
Maxuel Oliveira Andrade ◽  
Marco Aurélio Takita ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Xanthan Gum ◽  
Wild Type Strain ◽  
Natural Infection ◽  
Citrus Canker ◽  
Wild Type ◽  
Xanthomonas Citri ◽  
Canker Disease ◽  
Key Enzyme ◽  
Citrus Canker Disease

Xanthomonas citri subsp. citri (X. citri) is a plant pathogenic bacterium causing citrus canker disease. The xanA gene encodes a phosphoglucomutase/phosphomannomutase protein that is a key enzyme required for the synthesis of lipopolysaccharides and exopolysaccharides in Xanthomonads. In this work, firstly we isolated a xanA transposon mutant (xanA::Tn5) and analyzed its phenotypes as biofilm formation, xanthan gum production, and pathogenesis on the sweet orange host. Moreover, to confirm the xanA role in the impaired phenotypes we further produced a non-polar deletion mutant (ΔxanA) and performed the complementation of both xanA mutants. In addition, we analyzed the percentages of the xanthan gum monosaccharides produced by X. citri wild-type and xanA mutant. The mutant strain had higher ratios of mannose, galactose, and xylose and lower ratios of rhamnose, glucuronic acid, and glucose than the wild-type strain. Such changes in the saccharide composition led to the reduction of xanthan yield in the xanA deficient strain, affecting also other important features in X. citri, such as biofilm formation and sliding motility. Moreover, we showed that xanA::Tn5 caused no symptoms on host leaves after spraying, a method that mimetics the natural infection condition. These results suggest that xanA plays an important role in the epiphytical stage on the leaves that is essential for the successful interaction with the host, including adaptive advantage for bacterial X. citri survival and host invasion, which culminates in pathogenicity.

scholarly journals GC-TOF/MS-based metabolomics analysis to investigate the changes driven by N-Acetylcysteine in the plant-pathogen Xanthomonas citri subsp. citri

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Simone Cristina Picchi ◽  
Mariana de Souza e Silva ◽  
Luiz Leonardo Saldanha ◽  
Henrique Ferreira ◽  
Marco Aurélio Takita ◽  
...  
Keyword(s):  
Amino Acids ◽  
Cell Proliferation ◽  
Plant Pathogen ◽  
Model Organism ◽  
Citrus Canker ◽  
Bacterial Cells ◽  
Xanthomonas Citri ◽  
Canker Disease ◽  
Potential Use

AbstractN-Acetylcysteine (NAC) is an antioxidant, anti-adhesive, and antimicrobial compound. Even though there is much information regarding the role of NAC as an antioxidant and anti-adhesive agent, little is known about its antimicrobial activity. In order to assess its mode of action in bacterial cells, we investigated the metabolic responses triggered by NAC at neutral pH. As a model organism, we chose the Gram-negative plant pathogen Xanthomonas citri subsp. citri (X. citri), the causal agent of citrus canker disease, due to the potential use of NAC as a sustainable molecule against phytopathogens dissemination in citrus cultivated areas. In presence of NAC, cell proliferation was affected after 4 h, but damages to the cell membrane were observed only after 24 h. Targeted metabolite profiling analysis using GC–MS/TOF unravelled that NAC seems to be metabolized by the cells affecting cysteine metabolism. Intriguingly, glutamine, a marker for nitrogen status, was not detected among the cells treated with NAC. The absence of glutamine was followed by a decrease in the levels of the majority of the proteinogenic amino acids, suggesting that the reduced availability of amino acids affect protein synthesis and consequently cell proliferation.

Development of genetic maps of the citrus varieties ‘Murcott’ tangor and ‘Pêra’ sweet orange by using fluorescent AFLP markers

2007 ◽  
Vol 48 (3) ◽  
pp. 219-231 ◽  
Author(s):  
Antonio Carlos de Oliveira ◽  
Marinês Bastianel ◽  
Mariângela Cristofani-Yaly ◽  
Alexandre Morais do Amaral ◽  
Marcos Antonio Machado
Keyword(s):  
Sweet Orange ◽  
Genetic Maps ◽  
Aflp Markers ◽  
Citrus Varieties

scholarly journals First Report from Syria of Citrus tristeza virus in Citrus spp.

Plant Disease ◽  
2008 ◽  
Vol 92 (10) ◽  
pp. 1468-1468
Author(s):  
R. Abou Kubaa ◽  
K. Djelouah ◽  
A. M. D'Onghia ◽  
R. Addante ◽  
M. Jamal
Keyword(s):  
Citrus Tristeza Virus ◽  
Sweet Orange ◽  
Citrus Limon ◽  
Potential Threat ◽  
First Report ◽  
Mexican Lime ◽  
Vein Clearing ◽  
Citrus Varieties ◽  
Tristeza Virus ◽  
Citrus Tristeza

During the spring of 2006, the main Syrian citrus-growing areas of Lattakia (Jableh, Aledyye, Eseelya, Siano, and Hresoon provinces) and Tartous (Almintar, Aljammase, Karto, Majdaloonelbahr, Yahmour, Amreet, Althawra, and Safita provinces) were surveyed to assess the presence of Citrus tristeza virus (CTV). Eight nurseries (approximately 130 plants per nursery), two budwood source fields (approximately 230 trees per field), and 19 groves (approximately 60 trees per grove) containing the main citrus varieties were visually inspected and sampled for serological assays. The hierarchical sampling method was carried out in each selected grove (2). Infected samples were collected from two nurseries, two budwood source fields, and six groves. Stems and leaf petioles from nursery trees and flower explants from the groves were collected and analyzed for CTV by direct tissue blot immunoassay (DTBIA) with the commercial kit from Plantprint (Valencia, Spain). Of 2,653 samples tested, 89 (4%) CTV-infected plants were detected. Five citrus varieties were found to be infected and Meyer lemon (Citrus limon ‘Meyer’) had the highest incidence at 16%. Numerous sweet orange varieties (Citrus sinensis L.) were found to be highly infected in the field, but only the Washington navel sweet orange was found to be infected in the nurseries. No clear CTV symptoms were observed during the survey. Samples that were positive for CTV by DTBIA were also positive by biological indexing on Mexican lime (C. aurantifolia) and immunocapture-reverse transcription-PCR as described by Nolasco et al. (3). Coat protein gene sequences obtained from five selected clones of a Syrian CTV isolate (GenBank Accession No. EU626555) showed more than 99 and 98% nucleotide sequence identity to a Jordanian CTV isolate (GenBank Accession No. AY550252) and the VT isolate (GenBank Accession No. U56902), respectively. Almost all infected samples induced moderate vein clearing symptoms when grafted to Mexican lime. Symptoms of vein clearing, leaf cupping, stunting, and stem pitting on Mexican lime were induced by graft transmission of CTV from one Valencia sample from the Tartous area. The viral inoculum is widely and randomly distributed in commercial groves, especially in the southern Tartous area and in some nurseries. To our knowledge, this is the first report of CTV in Syria. However, CTV was reported from the neighboring citrus-growing countries of Lebanon, Turkey, and Jordan (1), and the severe seedling yellows strain is present in this area, which poses a potential threat to Syrian citriculture. References: (1) G. H. Anfoka et al. Phytopathol. Mediterr. 44:17, 2005. (2) G. Hughes and T. R. Gottwald, Phytopathology 88:715, 1998. (3) G. Nolasco et al. Eur. J. Plant Pathol. 108:293, 2002.

scholarly journals Diversity Analysis of Endophytic Bacterial Community in Two Citrus Cultivars With Different Resistance to Citrus Canker

2021 ◽  
Author(s):  
Bing Liu ◽  
Jiahao Lai ◽  
Simeng Wu ◽  
Junxi Jiang ◽  
Weigang Kuang
Keyword(s):  
Bacterial Community ◽  
Endophytic Bacteria ◽  
Citrus Canker ◽  
Navel Orange ◽  
Xanthomonas Citri ◽  
Canker Disease ◽  
Satsuma Mandarin ◽  
Endophytic Bacterial Community ◽  
Dominant Bacteria ◽  
The Relationship

Abstract The selective infection of Xanthomonas citri pv. citri to citrus cultivars is universally known, but it is not clarified whether there is a relationship between endophytic bacteria and the resistance of host variety to canker disease. In order to explore the relationship, Satsuma mandarin and Newhall navel orange were collected respectively as samples of resistant or susceptible cultivars to citrus canker disease, and endophytic bacterial community of two citrus cultivars were analyzed by using a next-generation, Illumina-based sequencing approach. Simultaneously, the seasonal dynamics of endophytic bacterial community and dominant genera were analyzed. The results showed that there were four dominant groups including Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes in all samples at phylum level. Endophytic bacteria were the most abundant in spring samples, then in summer and autumn samples. There were some differences between endophytic bacterial community of resistant citrus and that of susceptible citrus to canker disease, and the endophytic bacteria of Satsuma mandarin are more abundant than that of Newhall navel orange. According to the analysis of dominant bacteria in two citrus cultivars, it was found that some endophytic bacteria with antagonistic characteristics existed universally in all samples, although the dominant bacteria in different seasonal sample were different. However, in Newhall navel orange of susceptible citrus to canker disease, there were not only some bacteria against Xanthomonas citri pv. citri, but also some cooperative bacteria of canker occurrence like Stenotrophomonas.

scholarly journals Biocontrol of Citrus Canker Disease Caused by Xanthomonas citri subsp. citri Using an Endophytic Bacillus thuringiensis

2019 ◽  
Vol 35 (5) ◽  
pp. 486-497 ◽  
Author(s):  
Md. Nurul Islam ◽  
Md. Sarafat Ali ◽  
Seong-Jin Choi ◽  
Jae-Wook Hyun ◽  
Kwang-Hyun Baek
Keyword(s):  
Bacillus Thuringiensis ◽  
Citrus Canker ◽  
Xanthomonas Citri ◽  
Canker Disease ◽  
Citrus Canker Disease

scholarly journals Induced resistance in sweet orange against Xanthomonas citri subsp. citri by hexanoic acid

2015 ◽  
Vol 74 ◽  
pp. 77-84 ◽  
Author(s):  
Eugenio Llorens ◽  
Begonya Vicedo ◽  
María M. López ◽  
Leonor Lapeña ◽  
James H. Graham ◽  
...  
Keyword(s):  
Induced Resistance ◽  
Sweet Orange ◽  
Hexanoic Acid ◽  
Xanthomonas Citri

scholarly journals Bismerthiazol Inhibits Xanthomonas citri subsp. citri Growth and Induces Differential Expression of Citrus Defense-Related Genes

2016 ◽  
Vol 106 (7) ◽  
pp. 693-701 ◽  
Author(s):  
Xiaoyue Yu ◽  
Cheryl M. Armstrong ◽  
Mingguo Zhou ◽  
Yongping Duan
Keyword(s):  
Defense Response ◽  
Citrus Canker ◽  
Economic Losses ◽  
Marker Genes ◽  
Flavonoid Pathway ◽  
Xanthomonas Citri ◽  
Pr Genes ◽  
Rice Bacterial Blight ◽  
Host Defense Response ◽  
Serious Disease

Citrus canker, caused by Xanthomonas citri ssp. citri, is a serious disease that causes substantial economic losses to the citrus industry worldwide. The bactericide bismerthiazol has been used to control rice bacterial blight (X. oryzae pv. oryzae). In this paper, we demonstrate that bismerthiazol can effectively control citrus canker by both inhibiting the growth of X. citri ssp. citri and triggering the plant’s host defense response through the expression of several pathogenesis-related genes (PR1, PR2, CHI, and RpRd1) and the nonexpresser of PR genes (NPR1, NPR2, and NPR3) in ‘Duncan’ grapefruit, especially at early treatment times. In addition, we found that bismerthiazol induced the expression of the marker genes CitCHS and CitCHI in the flavonoid pathway and the PAL1 (phenylalanine ammonia lyase 1) gene in the salicylic acid (SA) biosynthesis pathway at different time points. Moreover, bismerthiazol also induced the expression of the priming defense-associated gene AZI1. Taken together, these results indicate that the induction of the defense response in ‘Duncan’ grapefruit by bismerthiazol may involve the SA signaling pathway and the priming defense and that bismerthiazol may serve as an alternative to copper bactericides for the control of citrus canker.

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