Identification of a Plant Nitric Oxide Synthase Gene Involved in Hormonal Signaling

Fang-Qing Guo, Mamoru Okamoto, and Nigel M. Crawford
Science Oct 3 2003: 100-103. [Abstract] [Full Text] [PDF] [Supporting Online Material]  
Nitric oxide (NO) serves as a signal in plants. An Arabidopsis mutant (Atnos1) was identified

that had impaired NO production, organ growth, and abscisic acid–induced stomatal movements.

Expression of AtNOS1 with a viral promoter in Atnos1 mutant plants resulted in overproduction of NO. Purified AtNOS1 protein

used the substrates arginine and nicotinamide adenine dinucleotide phosphate and was activated by Ca2+ and

calmodulin-like mammalian endothelial nitric oxide synthase and neuronal nitric oxide synthase, yet it is a distinct enzyme with no sequence similarities to any mammalian isoform. Thus, AtNOS1 encodes a distinct nitric oxide synthase that regulates growth and hormonal signaling in plants.

Section of Cell and Developmental Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093–0116, USA.