About the Cover
The WRKY family of transcription factors is best known from members
that are expressed in response to pathogen infection, mechanical
damage, and senescence. On pages 1359-1375, Johnson et al. now
report that one member of this family in Arabidopsis, WRKY44, plays a
different role. The cover shows a wild-type trichome on the surface of
an Arabidopsis leaf. In mutants that lack WRK44 function, fewer
trichomes arise and they are unbranched. Seed coat (testa) development
is also compromised -- mucilage and tannin are lacking. The gene has been
named TRANSPARENT TESTA GLABRA2 (TTG2)
because ttg2 mutants share pleiotropic defects with
ttg1 mutants. TTG1 encodes a WD40 protein,
and its function is required for TTG2 expression in
tannin-producing cells but not in trichomes.
[Table of Contents]
Copyright © 2007 by the American Society of Plant Biologists
