TY - JOUR
T1 - Regulatory mechanisms of ROI generation are affected by rice spl mutations
AU - Kojo, Kaori
AU - Yaeno, Takashi
AU - Kusumi, Kensuke
AU - Matsumura, Hideo
AU - Fujisawa, Shizuko
AU - Terauchi, Ryohei
AU - Iba, Koh
PY - 2006/8
Y1 - 2006/8
N2 - Reactive oxygen intermediates (ROIs) play a pivotal role in the hypersensitive response (HR) in disease resistance. NADPH oxidase is a major source of ROI; however, the mechanisms of its regulation are unclear. Rice spl mutants spontaneously form lesions which resemble those occurring during the HR, suggesting that the mutations affect regulation of the HR. We found that spl2, spl7 and spl11 mutant cells accumulated increased amounts of H2O 2 in response to rice blast fungal elicitor. Increased accumulation of ROIs was suppressed by inhibition of NADPH oxidase in the spl cells, and was also observed in the ozone-exposed spl plants. These mutants have sufficient activities of ROI-scavenging enzymes compared with the wild type. In addition, spl7 mutant cells accumulated higher amounts of H2O2 when treated with calyculin A (CA), an inhibitor of protein phosphatase. Furthermore, spl2 mutant plants exhibited accelerated accumulation of H2O 2 and increased rates of cell death in response to wounding. These results suggest that the spl2, spl7 and spl11 mutants are defective in the regulation of NADPH oxidase, and the spl7 mutation may give rise to enhancement of the signaling pathway which protein dephosphorylation controls, while the spl2 mutation affects both the pathogen-induced and wound-induced signaling pathways.
AB - Reactive oxygen intermediates (ROIs) play a pivotal role in the hypersensitive response (HR) in disease resistance. NADPH oxidase is a major source of ROI; however, the mechanisms of its regulation are unclear. Rice spl mutants spontaneously form lesions which resemble those occurring during the HR, suggesting that the mutations affect regulation of the HR. We found that spl2, spl7 and spl11 mutant cells accumulated increased amounts of H2O 2 in response to rice blast fungal elicitor. Increased accumulation of ROIs was suppressed by inhibition of NADPH oxidase in the spl cells, and was also observed in the ozone-exposed spl plants. These mutants have sufficient activities of ROI-scavenging enzymes compared with the wild type. In addition, spl7 mutant cells accumulated higher amounts of H2O2 when treated with calyculin A (CA), an inhibitor of protein phosphatase. Furthermore, spl2 mutant plants exhibited accelerated accumulation of H2O 2 and increased rates of cell death in response to wounding. These results suggest that the spl2, spl7 and spl11 mutants are defective in the regulation of NADPH oxidase, and the spl7 mutation may give rise to enhancement of the signaling pathway which protein dephosphorylation controls, while the spl2 mutation affects both the pathogen-induced and wound-induced signaling pathways.
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U2 - 10.1093/pcp/pcj074
DO - 10.1093/pcp/pcj074
M3 - Article
C2 - 16816407
AN - SCOPUS:33749017063
VL - 47
SP - 1035
EP - 1044
JO - Plant and Cell Physiology
JF - Plant and Cell Physiology
SN - 0032-0781
IS - 8
ER -