A new plant SGS2 gene involved in encoding an RNA-dependent RNA polymerase and in transgene silencing, increases transgene stability and expression in transgenic plants when it is inactivated

摘要

A polynucleotide comprising a plant SGS2 gene is new. Independent claims are also included for: (i) a polynucleotide comprising a sequence encoding a sequence encoding a plant SGS2 gene; (ii) a polynucleotide encoding a polypeptide having the 1196 amino acid sequence fully defined in the specification (I), or a fragment of at least 15 amino acid residues of sequence I; (iii) a polynucleotide comprising a sequence antisense to a sequence encoding a plant SGS2 gene; (iv) a polynucleotide comprising the promoter of a plant SGS2 gene; (v) an expression cassette comprising (a) a promoter functional in a host organism (b) a polynucleotide according to the main claim or additional claims (i) - (iii) inclusive, and (c) a terminator sequence functional in the above host organism; (vi) an expression cassette comprising (a) the above promoter (b) a polynucleotide encoding a heterologous polypeptide, and (c) a terminator sequence functional in plant cells; (vii) an expression vector for transformation comprising one of the above polynucleotides; (viii) a transformation procedure for host organisms, particularly plant cells or plants, comprising integration of one of the above polynucleotides into the organism; (ix) expressing a heterologous gene in a plant, comprising transforming the plant with the heterologous gene and inhibiting SGS2 expression or inactivating the SGS2 gene in that plant; (x) a transformed host organism comprising one of the above polynucleotides; (xi) a host organism comprising an inactive SGS2 plant gene; (xii) an SGS2 polypeptide comprising (a) the 6863 nt sequence fully defined in the specification (II) (b) a polypeptide 90% homologous to sequence II, or (c) a fragment of at least 15 amino acids of (a) or (b); and (xiii) using a fragment of one of the claimed polynucleotides to identify a plant SGS2 gene or SGS2 mutants.