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Characterization and expression of cytokinin signalling genes in sulfur deficient grapevine (Vitis vinifera L.)
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Orientador(es)
Resumo(s)
Sulfur (S) is an essential macronutrient for plant growth and development. In vitro grapevine
callus, cells and shoots in culture media in the absence of sulfur (-S) respond markedly with
a reduction of growth and shoot multiplication. This may result from an interference of -S with
cytokinin signal pathway (CSP) or at shoot apical meristem (SAM) or axillary meristem (AM)
identity level. Cytokinins are essential plant hormones that control various processes in
plants. As in Arabidopsis, Vitis CSP is composed by receptors (HKs), phosphotransmitters
(HPTs) and two types of response regulators (A-type and B-type RRs). Cells in -S in the
presence of cytokinin show a downregulation of most CSP genes while -S without cytokinin
leads to an upregulation of A-type RRs. CSP is not significantly affected by –S in in vitro
shoots, so the multiplication inhibition can be caused by a downregulation of the expression
of SAM and AM identity genes, respectively STM and LAS. In vitro conditions more similar to
autotrophy as Temporary Immersion System, the scarce multiplication impairment must
result from the reduction of B-type RRs transcription. As a whole the present work provides
new insights on the crosstalk between –S and cytokinin signaling in in vitro grapevine model
systems.
Descrição
Mestrado em Engenharia Agronómica - Instituto Superior de Agronomia
Palavras-chave
vitis vinifera apical meristem axillary meristem cytokinin signalling pathway sulfur videira meristema apical meristema axilar via de sinalização das citocininas