Satoshi Nakaba1, Izumi Arakawa2, Hikaru Morimoto2, Ryogo Nakada3, Nobumasa Bito4, Takanori Imai4, Ryo Funada2. 1. Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan. nakaba@cc.tuat.ac.jp. 2. Faculty of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan. 3. Forestry and Forest Products Research Institute, Forest Tree Breeding Center, Hokkaido Regional Breeding Office, 561-1 Bunkyodai-midorimachi, Ebetsu, Hokkaido, 069-0836, Japan. 4. Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan.
Abstract
MAIN CONCLUSION: The work demonstrates a relationship between the biosynthesis of the secondary metabolite, agatharesinol, and cytological changes that occur in ray parenchyma during cell death in sapwood sticks of Cryptomeria japonica under humidity-regulated conditions. To characterize the death of ray parenchyma cells that accompanies the biosynthesis of secondary metabolites, we examined cell death in sapwood sticks of Cryptomeria japonica under humidity-regulated conditions. We monitored features of ray parenchyma cells, such as viability, the morphology of nuclei and vacuoles, and the amount of starch grains. In addition, we analyzed levels of agatharesinol, a heartwood norlignan, by gas chromatography-mass spectrometry in the same sapwood sticks. Dramatic changes in the amount of starch grains and in the level of agatharesinol occurred simultaneously. Therefore, the biosynthesis of agatharesinol appeared to originate from the breakdown of starch. Furthermore, we observed the expansion of vacuoles in ray parenchyma cells prior to other cytological changes at the final stage of cell death. In our experimental system, we were able to follow the process of cell death and to demonstrate relationships between cytological changes and the biosynthesis of a secondary metabolite during the death of ray parenchyma cells.
MAIN CONCLUSION: The work demonstrates a relationship between the biosynthesis of the secondary metabolite, agatharesinol, and cytological changes that occur in ray parenchyma during cell death in sapwood sticks of Cryptomeria japonica under humidity-regulated conditions. To characterize the death of ray parenchyma cells that accompanies the biosynthesis of secondary metabolites, we examined cell death in sapwood sticks of Cryptomeria japonica under humidity-regulated conditions. We monitored features of ray parenchyma cells, such as viability, the morphology of nuclei and vacuoles, and the amount of starch grains. In addition, we analyzed levels of agatharesinol, a heartwood norlignan, by gas chromatography-mass spectrometry in the same sapwood sticks. Dramatic changes in the amount of starch grains and in the level of agatharesinol occurred simultaneously. Therefore, the biosynthesis of agatharesinol appeared to originate from the breakdown of starch. Furthermore, we observed the expansion of vacuoles in ray parenchyma cells prior to other cytological changes at the final stage of cell death. In our experimental system, we were able to follow the process of cell death and to demonstrate relationships between cytological changes and the biosynthesis of a secondary metabolite during the death of ray parenchyma cells.
Authors: W G van Doorn; E P Beers; J L Dangl; V E Franklin-Tong; P Gallois; I Hara-Nishimura; A M Jones; M Kawai-Yamada; E Lam; J Mundy; L A J Mur; M Petersen; A Smertenko; M Taliansky; F Van Breusegem; T Wolpert; E Woltering; B Zhivotovsky; P V Bozhkov Journal: Cell Death Differ Date: 2011-04-15 Impact factor: 15.828
Authors: Joseph G Dubrovsky; Martin Guttenberger; Andres Saralegui; Selene Napsucialy-Mendivil; Boris Voigt; Frantisek Baluska; Diedrik Menzel Journal: Ann Bot Date: 2006-03-06 Impact factor: 4.357