Nitric oxide, a signaling molecule in plant cell reactivation

Abstract

Nitric oxide is known to act as a biological messenger in divers signal transduction pathways in animal organisms. Initial investigations suggest that plants use nitric oxide as a signaling molecule via pathways remarkably similar to those found in mammals. Especially, the siganiling role of NO during plant defense reactions is well established. However, mounting evidences support the hypothesis that NO is a more general effector of plant growth and development. In our laboratory, alfalfa cell cultures were used to investigate the possible involvement of NO in the regulation of cell division and differentiation in plant cells. The homogenous population of leaf protoplasts were cultured in the presence of a NO donor, sodium nitroprusside (SNP) and/or an inhibitor, NG-monomethyl-L-arginine (L-NMMA). BrdU incorporation frequency into the nuclei of the protoplast-derived cells indicated that the entry into the S-phase of the cell cycle is enhanced by SNP and inhibited by L-NMMA treatments, respectively (see Figure 1). Experiments have also been carried out with continuously dividing cell suspension cultures. The obtained data indicated that these type of cells are insensitive to similar treatments shown to affect protoplast-derived cell division (see Figure 2). Cell Biology of Nitric Oxide and Cell Death in Plants Meeting abstracts BrdU incorporation frequency into the nuclei of leaf prot-plast-derived alfalfa cells during the third day of culture Figure 1 BrdU incorporation frequency into the nuclei of leaf prot-plast-derived alfalfa cells during the third day of culture. The cells were treated by the indicated drugs affecting endog-enous NO formation. For cell culture details see [2]. BrdU incorporation frequency into the nuclei of cell suspension cultured alfalfa cells during the third day after subculture Figure 2 BrdU incorporation frequency into the nuclei of cell suspension cultured alfalfa cells during the third day after subcul-ture. The cells were treated by the indicated drugs affecting endogenous NO formation. For cell culture details see [2].