Growth Deficiency of a <i>Xanthomonas oryzae</i> pv. <i>oryzae fur</i> Mutant in Rice Leaves Is Rescued by Ascorbic Acid Supplementation

Subramoni, Sujatha; Sonti, Ramesh V.

doi:10.1094/mpmi-18-0644

Cited by 51 publications

(47 citation statements)

References 49 publications

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“…2). To investigate this, we performed H 2 O 2 inhibition zone assays (43,49) with the catalase mutant strains. In this assay, bacteria are plated on solid KB media and H 2 O 2 is spotted onto a filter paper disk placed in the center of the plate.…”

Section: Resultsmentioning

confidence: 99%

Pseudomonas syringae Catalases Are Collectively Required for Plant Pathogenesis

et al. 2012

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ABSTRACTThe bacterial pathogenPseudomonas syringaepv. tomato DC3000 must detoxify plant-produced hydrogen peroxide (H2O2) in order to survive in its host plant. Candidate enzymes for this detoxification include the monofunctional catalases KatB and KatE and the bifunctional catalase-peroxidase KatG of DC3000. This study shows that KatG is the major housekeeping catalase of DC3000 and provides protection against menadione-generated endogenous H2O2. In contrast, KatB rapidly and substantially accumulates in response to exogenous H2O2. Furthermore, KatB and KatG have nonredundant roles in detoxifying exogenous H2O2and are required for full virulence of DC3000 inArabidopsis thaliana. Therefore, the nonredundant ability of KatB and KatG to detoxify plant-produced H2O2is essential for the bacteria to survive in plants. Indeed, a DC3000 catalase triple mutant is severely compromised in its ability to growin planta, and its growth can be partially rescued by the expression ofkatB,katE, orkatG. Interestingly, our data demonstrate that although KatB and KatG are the major catalases involved in the virulence of DC3000, KatE can also provide some protectionin planta. Thus, our results indicate that these catalases are virulence factors for DC3000 and are collectively required for pathogenesis.

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Section: Resultsmentioning

confidence: 99%

Pseudomonas syringae Catalases Are Collectively Required for Plant Pathogenesis

et al. 2012

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“…Controlling intracellular iron levels and modulating antioxidant responses therefore are crucial tasks for pathogenic bacteria during infection. The iron-dependent transcriptional regulator has been reported to play a key role in both adjusting intracellular iron levels and controlling oxidative stress responses during host plant-pathogen interactions (11,26). The role of RirA in iron regulation and oxidative stress response has not been studied in A. tumefaciens.…”

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confidence: 99%

Roles of Agrobacterium tumefaciens RirA in Iron Regulation, Oxidative Stress Response, and Virulence

et al. 2009

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The analysis of genetics and physiological functions of Agrobacterium tumefaciens RirA (rhizobial iron regulator) has shown that it is a transcription regulator and a repressor of iron uptake systems. The rirA mutant strain (NTLrirA) overproduced siderophores and exhibited a highly constitutive expression of genes involved in iron uptake (fhuA, irp6A, and fbpA) compared to that of the wild-type strain (NTL4). The deregulation in the iron control of iron uptake in NTLrirA led to iron overload in the cell, which was supported by the observation that the NTLrirA mutant was more sensitive than wild-type NTL4 to an iron-activated antibiotic, streptonigrin. The NTLrirA mutant was more sensitive than the parental strain to oxidants, including hydrogen peroxide, organic hydroperoxide, and a superoxide generator, menadione. However, the addition of an iron chelator, 2,2-dipyridyl, reversed the mutant hypersensitivity to H 2 O 2 and organic hydroperoxide, indicating the role of iron in peroxide toxicity. Meanwhile, the reduced level of superoxide dismutase (SodBIII) was partly responsible for the menadione-sensitive phenotype of the NTLrirA mutant. The NTLrirA mutant showed a defect in tumorigenesis on tobacco leaves, which likely resulted from the increased sensitivity of NTLrirA to oxidants and the decreased ability of NTLrirA to induce virulence genes (virB and virE). These data demonstrated that RirA is important for A. tumefaciens during plant-pathogen interactions.

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“…campestris and X. oryzae pv. oryzae plants (Jittawuttipoka et al, 2010;Subramoni and Sonti, 2005). The mutations in ferric uptake regulator were also resulted in the reduction in virulence of X. oryzae pv.…”

Section: Discussionmentioning

confidence: 99%

“…oryzae and X. campestris pv. campestris on their host plants (Jittawuttipoka et al, 2010;Subramoni and Sonti, 2005).…”

Section: Discussionmentioning

confidence: 99%

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Hemin transported protein of Xanthomonas axonopodis pv. glycines functions on leaf colonization and virulence on soybean

Prathuangwong¹,

Athinuwat²,

Chuaboon³

et al. 2013

Afr. J. Microbiol. Res.

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Xanthomonas axonopodis pv. glycines (Xag) causes bacterial pustule disease on soybean. This bacterium is present worldwide around hot and humid growing regions such as Southeast Asia. To understand if the gene coding for hemin transport protein (hem) is involved in virulence of the pathogen in soybean, we generated a hem mutant in Xag by overlapping PCR mutagenesis. Disruption of hem significantly reduced the population size and the disease incidence when sprayed on soybean but not when injected directly to soybean. The hem mutant caused the hypersensitive response induction on tobacco as an Xag wildtype. Interestingly, the hem expression was also reduced when the Xag wildtype grow in planta. The hemin transporter protein involved in the production of extracellular polysaccharide, biofilm formation, motility and attachment but not for extracellular enzymes. This confirmed that epiphytic fitness of Xag strongly required hem functions. These results suggest that hem gene is essential for virulence of Xag on soybean during the infection process.

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Growth Deficiency of a Xanthomonas oryzae pv. oryzae fur Mutant in Rice Leaves Is Rescued by Ascorbic Acid Supplementation

Cited by 51 publications

References 49 publications

Pseudomonas syringae Catalases Are Collectively Required for Plant Pathogenesis

Pseudomonas syringae Catalases Are Collectively Required for Plant Pathogenesis

Roles of Agrobacterium tumefaciens RirA in Iron Regulation, Oxidative Stress Response, and Virulence

Hemin transported protein of Xanthomonas axonopodis pv. glycines functions on leaf colonization and virulence on soybean

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