Sex determination in Rumex acetosa, a dioecious plant with a complex XY1 Y2 sex chromosome system (females are XX and males are XY1 Y2 ), is not controlled by an active Y chromosome but depends on the ratio between the number of X chromosomes and autosomes. To gain insight into the molecular mechanisms of sex determination, we generated a subtracted cDNA library enriched in genes specifically or predominantly expressed in female floral buds in early stages of development, when sex determination mechanisms come into play. In the present paper, we report the molecular and functional characterization of FEM32, a gene encoding a protein that shares a common architecture with proteins in different plants, animals, bacteria and fungi of the aerolysin superfamily; many of these function as β pore-forming toxins. The expression analysis, assessed by northern blot, RT-PCR and in situ hybridization, demonstrates that this gene is specifically expressed in flowers in both early and late stages of development, although its transcripts accumulate much more in female flowers than in male flowers. The ectopic expression of FEM32 under both the constitutive promoter 35S and the flower-specific promoter AP3 in transgenic tobacco showed no obvious alteration in vegetative development but was able to alter floral organ growth and pollen fertility. The 35S::FEM32 and AP3::FEM32 transgenic lines showed a reduction in stamen development and pollen viability, as well as a diminution in fruit set, fruit development and seed production. Compared with other floral organs, pistil development was, however, enhanced in plants overexpressing FEM32. According to these effects, it is likely that FEM32 functions in Rumex by arresting stamen and pollen development during female flower development. The aerolysin-like pore-forming proteins of eukaryotes are mainly involved in defence mechanisms against bacteria, fungi and insects and are also involved in apoptosis and programmed cell death (PCD), a mechanism that could explain the role of FEM32 in Rumex sex determination.

• MeSH
• bakteriální toxiny klasifikace   genetika   MeSH
• cytotoxické proteiny tvořící póry klasifikace   genetika   MeSH
• fylogeneze MeSH
• geneticky modifikované rostliny MeSH
• květy genetika   růst a vývoj   MeSH
• neplodnost rostlin genetika   MeSH
• ovoce genetika   růst a vývoj   MeSH
• pyl genetika   růst a vývoj   MeSH
• regulace genové exprese u rostlin MeSH
• rostlinné proteiny klasifikace   genetika   MeSH
• Rumex genetika   růst a vývoj   MeSH
• sekvence aminokyselin MeSH
• sekvenční homologie aminokyselin MeSH
• semena rostlinná genetika   růst a vývoj   MeSH
• stanovení celkové genové exprese metody   MeSH
• tabák genetika   růst a vývoj   MeSH
• vývojová regulace genové exprese MeSH
• Publikační typ
• časopisecké články MeSH