A carregar...
Publicação
Cork-associated genes in the suberization dynamics of Arabidopsis tissues: a contribution for their functional characterization
| Nome: | Descrição: | Tamanho: | Formato: | |
|---|---|---|---|---|
| 1.23 MB | Adobe PDF |
Resumo(s)
Cork (or phellem), from cork oak (Quercus suber), is produced by the secondary meristem phellogen
(or cork cambium), and constitutes the external barrier that protects the tree trunk and roots. Despite its
socio-economic relevance little is known about the molecular mechanisms controlling cork formation.
Recently, a comparative transcriptomic study to phellogen/phellem and xylem tissues on cork oak
identified a list of candidate genes involved in phellogen activity and phellem differentiation.
Subsequent studies using the Arabidopsis root and hypocotyl models, during primary and secondary
growth, identified transcription factors possibly involved in root endodermis/periderm suberization:
WOX9/STIP, required for meristem growth and early development, and ANT, involved in floral organ
development. Here we further characterize WOX9 and ANT functions in Arabidopsis root endodermis
suberization. Reverse transcription quantitative real-time-PCR analysis of root-hypocotyl tissues,
targeting genes of the abscisic acid (ABA) pathway, revealed that lack of or over-expression of WOX9
significantly affects ABA biosynthesis and signaling, suggesting WOX9 might be a positive regulator of
suberization through regulation of the ABA pathway. Additionally, we built a genetic construct
expressing QsWOX9 under CaMV35S constitutive promoter, enabling complementation experiments to
study functional similarities between Arabidopsis and cork oak homologues. Histochemical analysis in
post-embryonic ant loss-of-function roots displayed only slight reduction in suberized zones. However,
through RT-qPCR targeting key genes of the suberin pathway in stem and root-hypocotyl tissues, we
demonstrated that lack of ANT alters the expression of genes involved in biosynthesis and assembly of
suberin monomers. Moreover, we showed that exogenous ABA induces suberization in ant seedlings.
The expression analysis of key ABA pathway genes in ant-9 root-hypocotyl tissues revealed the
reduction of biosynthesis and downregulation of signaling, suggesting ANT might be a positive regulator
of the ABA signaling. Overall, our results support a regulatory role for WOX9 and ANT in the
mechanisms underlying the suberization process.
Descrição
Tese de mestrado, Biologia Molecular e Genética, 2023, Universidade de Lisboa, Faculdade de Ciências
Palavras-chave
Periderme endoderme ácido abscísico (ABA) suberina fator de transcrição Teses de mestrado - 2024