Transcript abundances of LIM transcription factor, 4CL, CAld5H and CesAs affect wood properties in Eucalyptus globulus

Abstract

Eucalyptus globulus is the main hardwood species grown in pulpwood plantations in temperate regions of the world. We have cloned six genes influencing wood quality including the LIM domain transcription factor (LIM), 4-coumarate-CoA ligase (4CL), coniferaldehyde 5hydroxylase (CAld5H) and the three catalytic units of cellulose synthase (CesA), from E. globulus. The transcript abundances of LIM in basal stems of ten independent E. globulus lines showed similar patterns to those of 4CL. We investigated the correlation between gene transcript abundances and wood qualities such as Klason lignin (KL) content, syringaldehyde/vanillin (SAO ratio and holocellulose (HC) content. Expression of the LIM and 4CL were positively correlated with KL content. A highly significant positive correlation was observed between CAld5H expression and S/V ratio. Furthermore, a ratio of the sum of the transcript abundances of three CesAl, CesA2 and CesA3 to 4CL showed a positive correlation with a ratio of HC/KL content that positively correlated with the chemically extracted fiber content in this woody plant.