第1098回生物科学セミナー

Two Topics in Stomatal Transcriptome Analysis

Bernard Genty(Commissariat à l’ Energie Atomique et aux Energies Alternatives,Cadarache, France)

2016年04月19日(火)    16:00-17:20  理学部2号館 223号室   

Transcriptomes of guard cells in C3 Tareneya hassleriana and C4 Gynandropsis gynandra,
both belonging to Cleomaceae, were compared. While approximately 60% of Gene
Ontology terms previously associated with guard cells from the C3 model Arabidopsis
(Arabidopsis thaliana) are conserved, there is much less overlap between patterns of
individual gene expression. Most ion and CO2 signaling modules appear unchanged at the
transcript level in guard cells from C3 and C4 species, but major variations in transcripts
associated with carbon-related pathways known to influence stomatal behavior were
detected. Genes associated with C4 photosynthesis were more highly expressed in guard
cells of C4 compared with C3 leaves. Furthermore, we detected two major patterns of
cell-specific C4 gene expression within the C4 leaf. In the first, genes previously associated
with preferential expression in the bundle sheath showed continually decreasing
expression from bundle sheath to mesophyll to guard cells. In the second, expression was
maximal in the mesophyll compared with both guard cells and bundle sheath. These data
imply that at least two gene regulatory networks act to coordinate gene expression across
the bundle sheath, mesophyll, and guard cells in the C4 leaf.
What are stomata doing in the night? Transcriptome analyses of the wild type and
the opal (open all night long) mutants in the dark will open up the way for our further
understanding of stomatal physiology.