75 Integrating Membrane Transport with Male Gametophyte ... - TAIR

219 Analysis of a Mutant, #1-63, which Exhibit an Abnormal Expression Pattern of
FILAMENTOUS FLOWER
Koichi Toyokura 2 , Keiro Watanabe 1 , Noritaka Matsumoto 2 , Kiyotaka Okada 2, 1
1
CREST, JST, 2 Department of Botany, Graduate School of Science, Kyoto University
In Arabidopsis thaliana, adaxial side (upper side) and abaxial side (lower side) of leaves have different characteristics,
e.g. shapes of cells and number of trichomes. FILAMENTOUS FLOWER (FIL) is known to be expressed on the abaxial
side. When FIL is overexpressed under the control of CaMV 35S promoter, adaxial sides of the leaves are abaxialized,
and in severe case filamentous leaves with only abaxial characters are produced. These suggest that normal expression
pattern of FIL is required for establishing adaxial and abaxial properties. In order to understand the mechanisms of
controlling the ab-adaxiality, it is crucial to reveal the mechanisms of the regulation of FIL expression.
We screened several mutants from mutagenized FILp::GFP transformants, which express GFP on the abaxial side.
Using stereoscopic microscope, we obtained two different types of mutants: 18 T2 plants, in which GFP was detected
on the upper surface (adaxial side) of the young rosette leaves, and 256 T2 plants, in which the GFP fluorescence was
weak or not detected. Furthermore, we analyze the former type of the mutants using CLSM to confirm in which region
GFP was expressed in cellular level. We acquired 11 lines that expressed GFP in wider region than WT. Several lines
of these mutants had aberrant leaves. We analyze one of them, #1-63. This mutant shows the variation of shapes of the
leaves: narrow leaves, variegated leaves, and filamentous leaves. In this mutant, some leaves expressed GFP in broader
region, but other leaves expressed GFP in narrower region. We will also report the expression pattern of some adaxialside-specific
markers in the mutant and cloning of a responsible gene is still in progress.
220 NO VEIN, a Gene Necessary for Leaf-Vein Formation in Arabidopsis
Ryuji Tsugeki, Yoshinori Sumi, Kiyotaka Okada
Department of Botany, Graduate School of Science, Kyoto University, Kyoto, Japan
Toward understanding the mechanisms of formation of leaf-venation pattern, we have isolated and analyzed
Arabidopsis mutants defective in formation of leaf veins. Rosette leaves of no vein-1 mutant (nov-1) are narrow and have
much fewer veins than those of wild type. No vein is often observed in the first two rosette leaves of nov-1. Expression
patterns of ATHB8 in nov-1 suggest that NO VEIN gene (NOV) is necessary for prepro/procambial cell formation in leaves.
Local distribution of auxin, which is dynamically changed during the leaf development, is known to be prerequisite for
leaf-vascular formation. In nov-1, DR5 expression is disrupted, often confined to the margin in leaves. As judged by
DR5 expression in response to 2,4-D, auxin response in nov-1 is comparable to that in wild type. These data suggest
that NOV is required for proper auxin distribution during the leaf development. nov-2~5 mutants, which are likely to
be null alleles, exhibit embryo-defective phenotype such as reduction and fusion of cotyledons and abnormality in the
early step of vascular development. It has been reported that similar phenotype was observed in mutants defective in
polar transport of auxin. In the developing embryos of the null nov mutants, DR5 is ectopically expressed in the tips
of cotyledon primordia and in the suspensor, suggesting that NOV is required for proper auxin distribution also in the
embryonic development. Taken together, these suggest that NOV is required for formation of developmentally regulated
auxin-distribution pattern both in the leaf and in the embryo, and thereby necessary for development of the leaf vein and
embryo. NOV encodes a novel protein. The phenotype of nov mutants and expression pattern of marker genes in nov
mutants will be presented.