SERK and APOSTART. Candidate genes for apomixis in Poa pratensis.
Seed production generally requires the mating of opposite sex gametes. Apomixis, an asexual mode of reproduction, avoids both meiotic reduction and egg fertilization. The essential feature of apomixis is that an embryo is formed autonomously by parthenogenesis from an unreduced egg of an embryo sac generated through apomeiosis. If apomixis were well understood and harnessed, it could be exploited to indefinitely propagate superior hybrids or specific genotypes bearing complex gene sets. A more profound knowledge of the mechanisms that regulate reproductive events would contribute fundamentally to understanding the genetic control of the apomictic pathway. In Poa pratensis, we isolated and characterized two genes, PpSERK (SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE) and APOSTART. These full-length genes were recovered by rapid amplification of cDNA ends and their temporal and spatial expression patterns were assessed by reverse transcription-polymerase chain reaction and in situ hybridization, respectively. The expression of PpSERK and APOSTART differed in apomictic and sexual genotypes. Their putative role in cell-signaling transduction cascades and trafficking events required during sporogenesis, gametogenesis, and embryogenesis in plants is reported and discussed. We propose that, in nucellar cells of apomictic genotypes, PpSERK is the switch that channels embryo sac development and that it may also redirect signaling gene products to compartments other than their typical ones. The involvement of APOSTART in meiosis and programmed cell death is also discussed.
Albertini
Emidio
E
Department of Plant Biology and Agro-Environmental and Animal Biotechnology, University of Perugia, 06121 Perugia, Italy. emidalb@unipg.it
Marconi
Gianpiero
G
Reale
Lara
L
Barcaccia
Gianni
G
Porceddu
Andrea
A
Ferranti
Francesco
F
Falcinelli
Mario
M
D000595:Amino Acid Sequence; D016923:Cell Death; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000502:physiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000096:biosynthesis*; D031785:Poa / Q000378:metabolism*; D011494:Protein Kinases / Q000096:biosynthesis*; D012100:Reproduction, Asexual / Q000502:physiology*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D010940:Plant Proteins; D011494:Protein Kinases; C106294:SERK protein, plant