Abstract:
Many plant genes are known to be involved in the development of cambium and wood, but how the expression
and functional interaction of these genes determine the unique biology of wood remains largely
unknown. We used the soc1ful loss of function mutant – the woodiest genotype known in the otherwise
herbaceous model plant Arabidopsis – to investigate the expression and interactions of genes involved in
secondary growth (wood formation). Detailed anatomical observations of the stem in combination with
mRNA sequencing were used to assess transcriptome remodeling during xylogenesis in wild-type and
woody soc1ful plants. To interpret the transcriptome changes, we constructed functional gene association
networks of differentially expressed genes using the STRING database. This analysis revealed functionally
enriched gene association hubs that are differentially expressed in herbaceous and woody tissues. In particular,
we observed the differential expression of genes related to mechanical stress and jasmonate biosynthesis/
signaling during wood formation in soc1ful plants that may be an effect of greater tension within
woody tissues. Our results suggest that habit shifts from herbaceous to woody life forms observed in many
angiosperm lineages could have evolved convergently by genetic changes that modulate the gene expression
and interaction network, and thereby redeploy the conserved wood developmental program.
