The role of type III effectors from <i>Xanthomonas axonopodis</i> pv. <i>manihotis</i> in virulence and suppression of plant immunity

Medina, César A.; Reyes, Paola Andrea; Trujillo, Cesar; González, Juan Luis Jiménez; Bejarano, David Alejandro; Montenegro, Nathaly; Jacobs, Jonathan M.; Joe, Anna; Restrepo, Silvia; Alfano, James R.; Bernal, Adriana

doi:10.1111/mpp.12545

Cited by 35 publications

(37 citation statements)

References 110 publications

(155 reference statements)

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“…In X. axonopodis pv. manihotis, AvrBs2, XopX, and XopZ have been shown to be required for full virulence, core effectors XopN and XopQ to contribute redundantly to virulence, and AvrBs2 and XopR to suppress pathogen-associated molecular pattern-triggered immunity ( Medina et al, 2017 ). Among the non-core ICMP11055 T3Es present in most of the X. translucens strains compared, XopAP, which was shown in X. euvesicatoria strain 85-10 to contribute to virulence, enhances jasmonic acid (JA) production to activate JA-induced defenses and repress salicylic acid-induced defense reactions ( Teper et al, 2015 ).…”

Section: Discussionmentioning

confidence: 99%

Complete Genome Sequencing and Targeted Mutagenesis Reveal Virulence Contributions of Tal2 and Tal4b of Xanthomonas translucens pv. undulosa ICMP11055 in Bacterial Leaf Streak of Wheat

et al. 2017

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Bacterial leaf streak caused by Xanthomonas translucens pv. undulosa (Xtu) is an important disease of wheat (Triticum aestivum) and barley (Hordeum vulgare) worldwide. Transcription activator-like effectors (TALEs) play determinative roles in many of the plant diseases caused by the different species and pathovars of Xanthomonas, but their role in this disease has not been characterized. ICMP11055 is a highly virulent Xtu strain from Iran. The aim of this study was to better understand genetic diversity of Xtu and to assess the role of TALEs in bacterial leaf streak of wheat by comparing the genome of this strain to the recently completely sequenced genome of a U.S. Xtu strain, and to several other draft X. translucens genomes, and by carrying out mutational analyses of the TALE (tal) genes the Iranian strain might harbor. The ICMP11055 genome, including its repeat-rich tal genes, was completely sequenced using single molecule, real-time technology (Pacific Biosciences). It consists of a single circular chromosome of 4,561,583 bp, containing 3,953 genes. Whole genome alignment with the genome of the United States Xtu strain XT4699 showed two major re-arrangements, nine genomic regions unique to ICMP11055, and one region unique to XT4699. ICMP110055 harbors 26 non-TALE type III effector genes and seven tal genes, compared to 25 and eight for XT4699. The tal genes occur singly or in pairs across five scattered loci. Four are identical to tal genes in XT4699. In addition to common repeat-variable diresidues (RVDs), the tal genes of ICMP11055, like those of XT4699, encode several RVDs rarely observed in Xanthomonas, including KG, NF, Y∗, YD, and YK. Insertion and deletion mutagenesis of ICMP11055 tal genes followed by genetic complementation analysis in wheat cv. Chinese Spring revealed that Tal2 and Tal4b of ICMP11055 each contribute individually to the extent of disease caused by this strain. A largely conserved ortholog of tal2 is present in XT4699, but for tal4b, only a gene with partial, fragmented RVD sequence similarity can be found. Our results lay the foundation for identification of important host genes activated by Xtu TALEs as targets for the development of disease resistant varieties.

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Section: Discussionmentioning

confidence: 99%

Complete Genome Sequencing and Targeted Mutagenesis Reveal Virulence Contributions of Tal2 and Tal4b of Xanthomonas translucens pv. undulosa ICMP11055 in Bacterial Leaf Streak of Wheat

et al. 2017

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“…On the other hand, the non-TAL effector gene avrBs2 is highly conserved in Xanthomonas spp. (Hajri et al 2009) and is required for the virulence of many Xanthomonas strains such X. euvesicatoria, Xac and Xam (Li et al 2015;Medina et al 2018). Consequently, the pepper Bs2 locus, which confer resistance upon recognition of AvrBs2, serves as a good candidate for durable field resistance.…”

Section: Generation Of Resistant Varieties Through Traditional Breedingmentioning

confidence: 99%

Mechanistic insights into host adaptation, virulence and epidemiology of the phytopathogenXanthomonas

Potnis

Dow

et al. 2019

FEMS Microbiology Reviews

186

165

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Xanthomonas is a well-studied genus of bacterial plant pathogens whose members cause a variety of diseases in economically important crops worldwide. Genomic and functional studies of these phytopathogens have provided significant understanding of microbial-host interactions, bacterial virulence and host adaptation mechanisms including microbial ecology and epidemiology. In addition, several strains of Xanthomonas are important as producers of the extracellular polysaccharide, xanthan, used in the food and pharmaceutical industries. This polymer has also been implicated in several phases of the bacterial disease cycle. In this review, we summarise the current knowledge on the infection strategies and regulatory networks controlling virulence and adaptation mechanisms from Xanthomonas species and discuss the novel opportunities that this body of work has provided for disease control and plant health.

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“…To date, there have been no reports of harpins derived from cassava pathogens. Cassava (Manihot esculenta Crantz) is a particularly important cash crop [18,19] in the tropics, where it is considered a staple crop and one of the main sources of calories for more than one billion people [18,20]. The most important bacterial disease of cassava is cassava bacterial blight, which is caused by the Gram-negative bacterium Xanthomonas phaseoli pv.…”

Section: Introductionmentioning

confidence: 99%

“…The most important bacterial disease of cassava is cassava bacterial blight, which is caused by the Gram-negative bacterium Xanthomonas phaseoli pv. manihotis (Xpm) [18,20]. The characterization of new harpin members improves our understanding of the evolutionary relationships of harpins and provides more possibilities for understanding the mechanism of harpins that underlies the interaction between pathogens and plants.…”

Section: Introductionmentioning

confidence: 99%

HpaXpm, a novel harpin of Xanthomonas phaseoli pv. manihotis, acts as an elicitor with high thermal stability, reduces disease, and promotes plant growth

et al. 2020

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Background: Harpins are proteins secreted by the type III secretion system of Gram-negative bacteria during pathogen-plant interactions that can act as elicitors, stimulating defense and plant growth in many types of nonhost plants. Harpin-treated plants have higher resistance, quality and yields and, therefore, harpin proteins may potentially have many valuable agricultural applications. Harpins are characterized by high thermal stability at 100°C. However, it is unknown whether harpins are still active at temperatures above 100°C or whether different temperatures affect the activity of the harpin protein in different ways. The mechanism responsible for the heat stability of harpins is also unknown. Results: We identified a novel harpin, HpaXpm, from the cassava blight bacteria Xanthomonas phaseoli pv. manihotis HNHK. The predicted secondary structure and 3-D structure indicated that the HpaXpm protein has two β-strand domains and two major α-helical domains located at the N-and C-terminal regions, respectively. A phylogenetic tree generated using the maximum likelihood method grouped HpaXpm in clade I of the Hpa1 group along with harpins produced by other Xanthomonas spp. (i.e., HpaG-Xag, HpaG-Xcm, Hpa1-Xac, and Hpa1Xm). Phenotypic assays showed that HpaXpm induced the hypersensitive response (HR), defense responses, and growth promotion in non-host plants more effectively than Hp1Xoo (X. oryzae pv. oryzae). Quantitative realtime PCR analysis indicated that HpaXpm proteins subjected to heat treatments at 100°C, 150°C, or 200°C were still able to stimulate the expression of function-related genes (i.e., the HR marker genes Hin1 and Hsr203J, the defense-related gene NPR1, and the plant growth enhancement-related gene NtEXP6); however, the ability of heattreated HpaXpm to induce HR was different at different temperatures. Conclusions: These findings add a new member to the harpin family. HpaXpm is heat-stable up to 200°C and is able to stimulate powerful beneficial biological functions that could potentially be more valuable for agricultural applications than those stimulated by Hpa1Xoo. We hypothesize that the extreme heat resistance of HpaXpm is because the structure of harpin is very stable and, therefore, the HpaXpm structure is less affected by temperature.

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The role of type III effectors from Xanthomonas axonopodis pv. manihotis in virulence and suppression of plant immunity

Cited by 35 publications

References 110 publications

Complete Genome Sequencing and Targeted Mutagenesis Reveal Virulence Contributions of Tal2 and Tal4b of Xanthomonas translucens pv. undulosa ICMP11055 in Bacterial Leaf Streak of Wheat

Complete Genome Sequencing and Targeted Mutagenesis Reveal Virulence Contributions of Tal2 and Tal4b of Xanthomonas translucens pv. undulosa ICMP11055 in Bacterial Leaf Streak of Wheat

Mechanistic insights into host adaptation, virulence and epidemiology of the phytopathogenXanthomonas

HpaXpm, a novel harpin of Xanthomonas phaseoli pv. manihotis, acts as an elicitor with high thermal stability, reduces disease, and promotes plant growth

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