Minisymposium 15: Pollen Biology
Add
this abstract to my Itinerary
Abs #
M1503: Female sporophytic Arabidopsis mutants impaired in pollen tube guidance
A pollen tube's journey to an egg cell within the pistil
involves cell to cell interactions such as attraction,
repulsion and adhesion. This journey begins with pollen
tube growing between the walls of the stigma cells,
travelling through the extracellular matrix of the
transmitting tissue, and finally arriving at the ovary,
where it migrates up the funiculus, and enter the micropyle
of an ovule to deliver the two sperm cells, one fertilizes
an egg and other the central cell. Thus a pollen tube
navigates past several different female cells before it
reaches the egg and seeds are not produced if the pollen
tube guidance process is disrupted.
To isolate pollen tube guidance signals from female
sporophytic cells, we performed a mutant screen by visually
selecting Arabidopsis plants with reduced seed
containing siliques from among the SALK TDNA insertion
collection. Mutations that cause reduction in seeds for
other reasons besides pollen tube growth and guidance
defects such as male sporophytic and gametophytic defects (reduced or lack of pollen), pollination defects (reduced or lack of pollen on the stigma), embryo and endosperm lethality (shriveled seeds) and fully
penetrant female gametophytic defects (~ half the number of
seeds) were eliminated from the screen. To date, primary screen of 5000 lines resulted in twenty candidate mutants. These
candidate lines were then subjected to a series of assays
to select only those lines that are impaired in pollen tube
guidance. Based on the progeny analyses and reciprocal crosses
to wild type plants we confirmed that at least two of these
lines are impaired in pollen tube guidance due to female
sporophytic tissue specific mutations. Progress on
microscopy and in vitro pollen tube
guidance analyses of mutants, and cloning the
genes that are tagged with TDNA will be reported.
