Regulation of quinolate phosphoribosyl transferase expression by transformation with a tobacco quinolate phosphoribosyl transferase nucleic acid

A transgenic plant of the species Nicotiana having reduced quinolate phosphoribosyl transferase (QPRTase) expression relative to a non-transformed control plant, said transgenic plant comprising transgenic plant cells containing:

• an exogenous DNA construct comprising in the 5′ to 3′ direction, a promoter operable in said plant cell and a heterologous DNA operably associated with said promoter;
• said plant exhibiting reduced QPRTase expression compared to a non-transformed control plant and;
• said heterologous DNA comprising a DNA sequence selected from the group consisting of:
• (a) the DNA sequence of SEQ ID NO:
• 1;
• (b) a DNA sequence which encodes an enzyme having the anion acid sequence of SEQ ID NO:
• 2;
• and
• (c) a DNA sequence which is at least 95% identical to the DNA sequence of (a) or (b) above, and which en quinolate phosphoribosyl transferase enzyme.

A method of making a transformed plant cell having reduced quinolate phosphoribosyl transferase (QPRTase) expression, said method comprising:

• providing a plant cell of a type known to express quinolate phosphoribosyl transferase;
• providing an exogenous DNA construct, which construct comprises, in the 5′ to 3′ direction, a promoter operable in a plant cell and a heterologous DNA operably associated with said promoter;
• and
• transforming said plant cell with said DNA construct to produce a transformed plant cell, wherein said transformed plant cell has reduced expression of QPRTase compared to an untransformed cell;
• and wherein said heterologous DNA comprising a DNA sequence is selected from the group consisting of:
• (a) the DNA sequence of SEQ ID) NO:
• 1;
• (b) a DNA sequence which encodes an enzyme having the amino acid sequence of SEQ ID NO:
• 2;
• and
• (c) DNA sequence which is at least 95% (b) above, and which encodes a quinolate phosphoribosyl transferase enzyme.

A method for reducing expression of a quinolate phosphoribosyl transferase gene in a plant cell, said method comprising:

• growing a plant cell transformed to contain a heterologous DNA, wherein a transcribed strand of said heterologous DNA is complementary to quinolate phosphoribosyl transferase mRNA endogenous to said cell, whereby transcription of said heterologous DNA reduces expression of said quinolate phosphoribosyl gene;
• said heterologous DNA comprising a DNA sequence selected from the group consisting of:
• (a) the DNA sequence of SEQ ID NO:
• 1;
• (b) a DNA sequence which encodes an enzyme having the amino acid sequence of SEQ ID NO:
• 2;
• and
• (c) a DNA sequence which is at least 95% identical to the DNA sequence of (a) or (b) above, and which en quinolate phosphoribosyl transferase enzyme.

A method of producing a tobacco plant having decreased levels of nicotine in leaves of said tobacco plant, said method comprising:

• Growing a tobacco plant wherein said plant comprises cells containing a DNA construct comprising a transcriptional initiation region functional in said plant and a heterologous DNA sequence operably joined to said transcriptional initiation region, wherein a transcribed strand of said heterologous DNA sequence is complementary to endogenous quinolate phosphoribosyl transferase messenger RNA cells in said cells;
• said heterologous DNA comprising a DNA sequence selected from the group consisting of:
• (a) the DNA sequence of SEQ ID NO:
• 1;
• (b) a DNA sequence which encodes an enzyme having the amino acid sequence of SEQ ID NO:
• 2;
• and
• (c) a DNA sequence which is at least 95% identical to the DNA sequence of (a) or (b) above, and which en quinolate phosphoribosyl transferase enzyme.