TITLE:
Diurnal Periodicity of the Expression of Genes Involved in Monolignol Biosynthesis in Differentiating Xylem of Cryptomeria japonica
AUTHORS:
Saori Sato, Masato Yoshida, Yousuke Ashizaki, Hiroyuki Yamamoto
KEYWORDS:
Cryptomeria japonica, Diurnal Periodicity, Monolignol, Secondary Wall, Tracheid
JOURNAL NAME:
American Journal of Plant Sciences,
Vol.7 No.17,
December
13,
2016
ABSTRACT: The cell wall in wood is mainly composed of three components: cellulose, hemicellulose
and lignin. According to electron microscopy observations of the innermost
surface of cell walls in the tracheids of Cryptomeria japonica , cellulose microfibrils
are deposited during the day and a matrix containing hemicellulose is deposited at
night. This indicates that the deposition of cell wall components exhibits diurnal periodicity.
To gain new insights into the diurnal periodicity of lignin deposition not
revealed by microscopic observations, we examined diurnal fluctuations in the expression
of genes involved in monolignol biosynthesis in C. japonica saplings grown
in the field and in growth chambers under a 12 h light/dark cycle. In the field experiment,
two gene expression peaks were observed daily, at dusk and dawn. In the
growth chamber experiment, two daily peaks were observed 0 h and 6 - 9 h after the
light switched on.