Arabidopsis gp91phox homologues AtrbohD and AtrbohF are required for accumulation of reactive oxygen intermediates in the plant defense response. Proceedings of the National Academy of Sciences of the United States of America, 99, 517-522

Department of Biology and Curriculum in Genetics and Molecular Biology, CB 3280, 108 Coker Hall, University of North Carolina, Chapel Hill, NC 27599-3280, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 02/2002; 99(1):517-22. DOI: 10.1073/pnas.012452499
Source: PubMed


Reactive oxygen intermediates (ROI) are strongly associated with plant defense responses. The origin of these ROI has been controversial. Arabidopsis respiratory burst oxidase homologues (rboh genes) have been proposed to play a role in ROI generation. We analyzed lines carrying dSpm insertions in the highly expressed AtrbohD and AtrbohF genes. Both are required for full ROI production observed during incompatible interactions with the bacterial pathogen Pseudomonas syringae pv. tomato DC3000(avrRpm1) and the oomycete parasite Peronospora parasitica. We also observed reduced cell death, visualized by trypan blue stain and reduced electrolyte leakage, in the Atrboh mutants after DC3000(avrRpm1) inoculation. However, enhanced cell death is observed after infection of mutant lines with P. parasitica. Paradoxically, although atrbohD mutation eliminated the majority of total ROI production, atrbohF mutation exhibited the strongest effect on cell death.

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    • "phenotype and reduced fertility ( Pineiro et al . , 2003 ) . EBS encodes a nuclear protein with homeodomain Zn finger that regulate chromatin remodeling and repress the initiation of flowering in short days . Pathogen recognition triggers generation of reactive oxygen intermediates ( ROIs ) , which is required for activation of defense responses ( Torres et al . , 2002 ) . It is also evident that the generation of ROI occurs within hours of pathogen infection ( Alvarez et al . , 1998 ) . Since PAP5 is induced only during the earlier stages ( 6 h . p . i ) of Pst DC3000 infection and the localization of PAP5 in peroxisome ( Figure 4 ) suggests that PAP5 may act as a component of ROI generation . Hence "
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    ABSTRACT: Plants possess an exceedingly complex innate immune system to defend against most pathogens. However, a relative proportion of the pathogens overcome host's innate immunity and impair plant growth and productivity. We previously showed that mutation in purple acid phosphatase (PAP5) lead to enhanced susceptibility of Arabidopsis to the bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (Pst DC3000). Here, we report that an optimal level of PAP5 is crucial for mounting complete basal resistance. Overexpression of PAP5 impaired ICS1, PR1 expression and salicylic acid (SA) accumulation similar to pap5 knockout mutant plants. Moreover, plant overexpressing PAP5 was impaired in H2O2 accumulation in response to Pst DC3000. PAP5 is localized in to peroxisomes, a known site of generation of reactive oxygen species for activation of defense responses. Taken together, our results demonstrate that optimal levels of PAP5 is required for mounting resistance against Pst DC3000 as both knockout and overexpression of PAP5 lead to compromised basal resistance.
    Frontiers in Plant Science 08/2015; 6:568. DOI:10.3389/fpls.2015.00568 · 3.95 Impact Factor
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    • "In contrast with the phenotypes observed in N. benthamiana, abolishment of H 2 O 2 production in rbohD plants reduced, rather than increased, sporangiophore development and fungal biomass upon inoculation with Peronospora parasitica (Torres et al., 2002) and Alternaria brassicicola (Pogá ny et al., 2009), respectively. The latter work also showed that the rbohD mutant is not affected in stress-related responses (Pogá ny et al., 2009) and indicates that RBOHD actually suppresses cell death (Torres et al., 2002; Pogá ny et al., 2009). "
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    • "Implication of ROS in the ABA signaling pathways leading to stomatal closure was confirmed by the identification of mutants of NADPH oxidases. These are plasma membrane enzymes responsible for ROS generation (Torres et al. 2002, Kwak et al. 2003). In the Arabidopsis NADPH oxidase double mutant atrbohD/F, ROS generation and stomatal closure normally observed upon ABA treatment are both reduced, confirming the importance of ROS in ABA effects (Kwak et al. 2003). "
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