Volume 18 Issue 5, May 2008: 577-588
ORIGINAL ARTICLES
Cross-talk between calcium-calmodulin and nitric oxide in abscisic acid signaling in leaves of maize plants
Jianrong Sang, Aying Zhang, Fan Lin, Mingpu Tan and Mingyi Jiang
1College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
Correspondence: Mingyi Jiang(myjiang@njau.edu.cn )
Using pharmacological and biochemical approaches, the signaling pathways between hydrogen peroxide (H
2O
2), calcium (Ca
2+)-calmodulin (CaM), and nitric oxide (NO) in abscisic acid (ABA)-induced antioxidant defense were investigated in leaves of maize (
Zea mays L.) plants. Treatments with ABA, H
2O
2, and CaCl
2 induced increases in the generation of NO in maize mesophyll cells and the activity of nitric oxide synthase (NOS) in the cytosolic and microsomal fractions of maize leaves. However, such increases were blocked by the pretreatments with Ca
2+ inhibitors and CaM antagonists. Meanwhile, pretreatments with two NOS inhibitors also suppressed the Ca
2+-induced increase in the production of NO. On the other hand, treatments with ABA and the NO donor sodium nitroprusside (SNP) also led to increases in the concentration of cytosolic Ca
2+ in protoplasts of mesophyll cells and in the expression of calmodulin 1 (
CaM1) gene and the contents of CaM in leaves of maize plants, and the increases induced by ABA were reduced by the pretreatments with a NO scavenger and a NOS inhibitor. Moreover, SNP-induced increases in 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 were arrested by the pretreatments with Ca
2+ inhibitors and CaM antagonists. Our results suggest that Ca
2+-CaM functions both upstream and downstream of NO production, which is mainly from NOS, in ABA- and H
2O
2-induced antioxidant defense in leaves of maize plants.
Cell Research (2008) 18:577-588. doi: 10.1038/cr.2008.39; published online 25 March 2008
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