Loss of chloroplast-localized protein phosphatase 2Cs in Arabidopsis thaliana
 leads to enhancement of plant immunity and resistance to Xanthomonas campestris
 pv. campestris
 infection

Xanthomonas campestris pv. campestris (Xcc) is a vascular pathogen of cruciferous plants that normally gains entry to plants via hydathodes. In order to study the basis of the preference for this portal of entry we have developed an Arabidopsis thaliana model with attached or detached leaves partially immersed in a bacterial suspension. Entry of bacteria into leaves, assessed by resistance to surface sterilization, could be detected after 1 h. Dissection of leaves and histochemical staining for β-glucuronidase produced by the bacteria indicated that they were located in hydathodes. In contrast, similar experiments with the leaf-spotting pathogen X. campestris pv. armoraciae gave patterns of localized staining dispersed over the leaf area, indicative of entry through stomata. A survey of 41 A. thaliana accessions showed that they fell into three classes distinguishable by total numbers of Xcc that entered under standard conditions and by preference for hydathode colonization. Previously isolated Xcc mutants affected in pathogenicity were tested for hydathode colonization: an hrp mutant behaved indistinguishably from the wild type, and rpf regulatory mutants gave 10-fold reduced colonization, whereas with rfaX mutants with altered lipopolysaccharide, few if any viable bacteria were recoverable from hydathodes. This fact, together with the rapid induction of superoxide dismutase in the bacteria located in hydathodes, suggests that an early defense reaction is mounted in the hydathode.

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Formate dehydrogenase contributes to the early Arabidopsis thaliana responses against Xanthomonas campestris pv campestris infection

Physiological and Molecular Plant Pathology ◽

10.1016/j.pmpp.2021.101633 ◽

2021 ◽

pp. 101633

Author(s):

Francesca Marzorati ◽

Gianpiero Vigani ◽

Piero Morandini ◽

Irene Murgia

Keyword(s):

Arabidopsis Thaliana ◽

Xanthomonas Campestris ◽

Formate Dehydrogenase ◽

Xanthomonas Campestris Pv Campestris

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Infection Assay for Xanthomonas campestris pv. campestris in Arabidopsis thaliana Mimicking Natural Entry via Hydathodes

Methods in Molecular Biology - Plant Innate Immunity ◽

10.1007/978-1-4939-9458-8_16 ◽

2019 ◽

pp. 159-185

Author(s):

Marieke van Hulten ◽

Sayantani Chatterjee ◽

Harrold A. van den Burg

Keyword(s):

Arabidopsis Thaliana ◽

Xanthomonas Campestris ◽

Infection Assay ◽

Xanthomonas Campestris Pv Campestris

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Natural variability in Arabidopsis thaliana germplasm response to Xanthomonas campestris pv. campestris

Fitopatologia Brasileira ◽

10.1590/s0100-41582007000200001 ◽

2007 ◽

Vol 32 (2) ◽

pp. 97-103 ◽

Cited By ~ 1

Author(s):

Lílian S.T. Carmo ◽

Elizabete S. Cândido ◽

Pollyanna F. Campos ◽

Alice Maria Quezado-Duval ◽

Eduardo Leonardecz ◽

...

Keyword(s):

Arabidopsis Thaliana ◽

Xanthomonas Campestris ◽

High Titer ◽

Continuous Light ◽

Brazilian Isolate ◽

Similar Reduction ◽

Disease Symptoms ◽

Model Plant Arabidopsis Thaliana ◽

Xanthomonas Campestris Pv Campestris ◽

Plant Arabidopsis Thaliana

This work aimed to study the interaction between the model plant Arabidopsis thaliana and Xanthomonas campestris pv. campestris (Xcc), the pathogen responsible for black rot of crucifers. The response of 32 accessions of A. thaliana to the Brazilian isolate of Xcc CNPH 17 was evaluated. No immunity-like response was observed. "CS1308", "CS1566" and "CS1643" grown in continuous light were among the accessions that showed strongest resistance when inoculated with 5 x 10(6) CFU/mL. In contrast, "CS1194" and "CS1492" were among the most susceptible accessions. Similar results were obtained when plants were grown under short-day conditions. To quantify the differences in disease symptoms, total chlorophyll was extracted from contrasting accessions at different time points after inoculation. Chlorophyll levels from controls and Xcc inoculated plants showed a similar reduction in resistant accessions, whereas Xcc-inoculated susceptible accessions showed a greater reduction compared to controls. To test the specificity of resistance, accessions CS1308, CS1566, CS1643 and CS1438 (which showed partial resistance to CNPH 17), were inoculated with a more aggressive isolate of Xcc (CNPH 77) and Ralstonia solanacearum. Among the accessions tested, "CS1566" was the most resistant to Xcc CNPH 77 and also displayed resistance to R. solanacearum. Accessions CS1308, CS1566 and CS1643 were also inoculated with a high titer of Xcc CNPH 17 (5 x 10(8) CFU/mL). No collapse of tissue was observed up to 48 h after inoculation, indicating that a hypersensitive response is not involved in the resistance displayed by these accessions.

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