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Calcium–calmodulin is required for abscisic acid‐induced antioxidant defense and functions both upstream and downstream of H 2 O 2 production in leaves of maize ( Zea mays ) plants
Author(s) -
Hu Xiuli,
Jiang Mingyi,
Zhang Jianhua,
Zhang Aying,
Lin Fan,
Tan Mingpu
Publication year - 2007
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2006.01888.x
Subject(s) - abscisic acid , antioxidant , reactive oxygen species , glutathione reductase , biochemistry , calmodulin , superoxide dismutase , cytosol , chemistry , calcium , glutathione , glutathione peroxidase , microbiology and biotechnology , enzyme , biology , gene , organic chemistry
Summary• Using pharmacological and biochemical approaches, the role of calmodulin (CaM) and the relationship between CaM and hydrogen peroxide (H 2 O 2 ) in abscisic acid (ABA)‐induced antioxidant defense in leaves of maize ( Zea mays ) plants were investigated. • Treatment with ABA or H 2 O 2 led to significant increases in the concentration of cytosolic Ca 2+ in the protoplasts of mesophyll cells and in the expression of the calmodulin 1 ( CaM1 ) gene and the content of CaM in leaves of maize plants, and enhanced the expression of the antioxidant genes superoxide dismutase 4 ( SOD4 ), cytosolic ascorbate peroxidase ( cAPX ), and glutathione reductase 1 ( GR1 ) and the activities of the chloroplastic and cytosolic antioxidant enzymes. The up‐regulation of the antioxidant enzymes was almost completely blocked by pretreatments with two CaM antagonists. • Pretreatments with CaM antagonists almost completely inhibited ABA‐induced H 2 O 2 production throughout ABA treatment, but pretreatment with an inhibitor or scavenger of reactive oxygen species (ROS) did not affect the initial increase in the contents of CaM induced by ABA. • Our results suggest that Ca 2+ –CaM is involved in ABA‐induced antioxidant defense, and that cross‐talk between Ca 2+ –CaM and H 2 O 2 plays a pivotal role in ABA signaling.