Mutations in AtPS1 (Arabidopsis thaliana parallel spindle 1) lead to the production of diploid pollen grains.
Polyploidy has had a considerable impact on the evolution of many eukaryotes, especially angiosperms. Indeed, most--if not all-angiosperms have experienced at least one round of polyploidy during the course of their evolution, and many important crop plants are current polyploids. The occurrence of 2n gametes (diplogametes) in diploid populations is widely recognised as the major source of polyploid formation. However, limited information is available on the genetic control of diplogamete production. Here, we describe the isolation and characterisation of the first gene, AtPS1 (Arabidopsis thaliana Parallel Spindle 1), implicated in the formation of a high frequency of diplogametes in plants. Atps1 mutants produce diploid male spores, diploid pollen grains, and spontaneous triploid plants in the next generation. Female meiosis is not affected in the mutant. We demonstrated that abnormal spindle orientation at male meiosis II leads to diplogamete formation. Most of the parent's heterozygosity is therefore conserved in the Atps1 diploid gametes, which is a key issue for plant breeding. The AtPS1 protein is conserved throughout the plant kingdom and carries domains suggestive of a regulatory function. The isolation of a gene involved in diplogamete production opens the way for new strategies in plant breeding programmes and progress in evolutionary studies.
d'Erfurth
Isabelle
I
French National Institute for Agricultural Research INRA, UR254, Versailles, France.
Jolivet
Sylvie
S
Froger
Nicole
N
Catrice
Olivier
O
Novatchkova
Maria
M
Simon
Mathieu
M
Jenczewski
Eric
E
Mercier
Raphaël
R
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D004171:Diploidy; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018745:Genome, Plant; D008969:Molecular Sequence Data; D009154:Mutation; D011058:Pollen / Q000235:genetics*; D011123:Polyploidy
D029681:Arabidopsis Proteins; C534518:PS1 protein, Arabidopsis