Am. Chaudhury et al., FERTILIZATION-INDEPENDENT SEED DEVELOPMENT IN ARABIDOPSIS-THALIANA, Proceedings of the National Academy of Sciences of the United Statesof America, 94(8), 1997, pp. 4223-4228
We report mutants in Arabidopsis thaliana (fertilization-independent s
eed:fis) in which certain processes of seed development are uncoupled
from the double fertilization event that occurs after pollination. The
se mutants were isolated as ethyl methanesulfonate-induced pseudo-reve
rtants of the pistillata phenotype. Although the pistillata (pi) mutan
t has short siliques devoid of seed, the fis mutants in the pi backgro
und have long siliques containing developing seeds, even though the fl
owers remain free of pollen. The three fis mutations map to loci on th
ree different chromosomes. In fis1 and fis2 seeds, the autonomous endo
sperm nuclei are diploid and the endosperm develops to the point of ce
llularization; the partially developed seeds then atrophy. In these tw
o mutants, proembryos are formed in a low proportion of seeds and do n
ot develop beyond the globular stage. When FIS/fis plants are pollinat
ed by pollen from FIS/FIS plants, approximate to 50% of the resulting
seeds contain fully developed embryos; these seeds germinate and form
viable seedlings (FIS/FIS). The other 50% of seeds shrivel and do not
germinate; they contain embryos arrested at the torpedo stage (FIS/fis
). In normal sexual reproduction, the products of the FIS genes are li
kely to play important regulatory roles in the development of seed aft
er fertilization.