Analysis of transposon insertion mutants highlights the diversity of mechanisms underlying male progamic development in Arabidopsis.
To identify genes with essential roles in male gametophytic development, including postpollination (progamic) events, we have undertaken a genetic screen based on segregation ratio distortion of a transposon-borne kanamycin-resistance marker. In a population of 3359 Arabidopsis Ds transposon insertion lines, we identified 20 mutants with stably reduced segregation ratios arising from reduced gametophytic transmission. All 20 mutants showed strict cosegregation of Ds and the reduced gametophytic transmission phenotype. Among these, 10 mutants affected both male and female transmission and 10 mutants showed male-specific transmission defects. Four male and female (ungud) mutants and 1 male-specific mutant showed cellular defects in microspores and/or in developing pollen. The 6 remaining ungud mutants and 9 male-specific (seth) mutants affected pollen functions during progamic development. In vitro and in vivo analyses are reported for 5 seth mutants. seth6 completely blocked pollen germination, while seth7 strongly reduced pollen germination efficiency and tube growth. In contrast, seth8, seth9, or seth10 pollen showed reduced competitive ability that was linked to slower rates of pollen tube growth. Gene sequences disrupted in seth insertions suggest essential functions for putative SETH proteins in diverse processes including protein anchoring, cell wall biosynthesis, signaling, and metabolism.
Lalanne
Eric
E
Department of Biology, University of Leicester, Leicester LE1 7RH, United Kingdom.
Michaelidis
Christos
C
Moore
James M
JM
Gagliano
Wendy
W
Johnson
Andrew
A
Patel
Ramesh
R
Howden
Ross
R
Vielle-Calzada
Jean-Phillippe
JP
Grossniklaus
Ueli
U
Twell
David
D
D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development; D001483:Base Sequence; D003001:Cloning, Molecular; D003433:Crosses, Genetic; D017931:DNA Primers; D014644:Genetic Variation; D016254:Mutagenesis, Insertional; D012098:Reproduction
D017931:DNA Primers