Reduced risk tobacco products and methods of making same

Abstract

Embodiments provided herein concern tobacco and tobacco products having a reduced amount of a harmful compound. More specifically, several embodiments concern approaches to modify the expression of a gene that is involved in the production of a harmful compound in tobacco, tobacco products made using these approaches and methods of determining whether the removal of said compounds using said approaches yields a tobacco and/or a tobacco product that has a reduced potential to contribute to a tobacco-related disease.

What is claimed: 
     
         1 . (canceled) 
     
     
         2 . A method of producing a transgenic tobacco plant comprising inhibiting expression of an endogenous gene encoding A622 in a tobacco plant, wherein said method further comprises introducing into said tobacco plant a nucleic acid molecule comprising a nucleic acid sequence selected from the group consisting of:
 a) the nucleic acid sequence of SEQ ID NO: 5;   b) a nucleic acid sequence comprising nucleotides 1-354 of the full length A622 cDNA;   c) a nucleic acid sequence comprising nucleotides 1-814 of the full length A622 cDNA;   d) a nucleic acid sequence comprising nucleotides 1-981 of the full length A622 cDNA;   e) a nucleic acid sequence comprising nucleotides 1-1160 of the full length A622 cDNA;   f) a nucleic acid sequence comprising nucleotides 1-1179 of the full length A622 cDNA;   g) a nucleic acid sequence comprising nucleotides 354-814 of the full length A622 cDNA;   h) a nucleic acid sequence comprising nucleotides 354-981 of the full length A622 cDNA;   i) a nucleic acid sequence comprising nucleotides 354-1160 of the full length A622 cDNA;   j) a nucleic acid sequence comprising nucleotides 354-1179 of the full length A622 cDNA;   k) a nucleic acid sequence comprising nucleotides 814-981 of the full length A622 cDNA;   l) a nucleic acid sequence comprising nucleotides 814-1160 of the full length A622 cDNA;   m) a nucleic acid sequence comprising nucleotides 814-1179 of the full length A622 cDNA;   n) a nucleic acid sequence comprising nucleotides 981-1160 of the full length A622 cDNA; and   o) a nucleic acid sequence comprising nucleotides 981-1179 of the full length A622 cDNA.   
     
     
         3 . The method of  claim 2 , wherein said nucleic acid molecule is operably linked to a heterologous nucleic acid. 
     
     
         4 . The method of  claim 3 , wherein said heterologous nucleic acid is a promoter. 
     
     
         5 . The method of  claim 2 , wherein said nucleic acid molecule confers a reduced expression of said endogenous A622 gene by interfering RNA (RNAi), sense-suppression, antisense suppression, targeted gene disruption, or enzymatic RNA. 
     
     
         6 . The method of  claim 2 , further comprising genetically engineering suppression of at least one additional gene encoding an enzyme of the nicotine biosynthetic pathway, wherein said at least one additional gene encodes an enzyme selected from the group consisting of arginine decarboxylase (ADC), methylputrescine oxidase (MPO), NADH dehydrogenase, ornithine decarboxylase (ODC), phosphoribosylanthranilate isomerase (PRAT), putrescine N-methyltransferase (PMT), quinolate phosphoribosyl transferase (QPT), and S-adenosyl-methionine synthetase (SAMS), or any combination thereof. 
     
     
         7 . A cured transgenic tobacco comprising a first heterologous nucleic acid molecule that comprises a nucleic acid sequence selected from the group consisting of:
 a) the nucleic acid sequence of SEQ ID NO: 5;   b) a nucleic acid sequence comprising nucleotides 1-354 of the full length A622 cDNA;   c) a nucleic acid sequence comprising nucleotides 1-814 of the full length A622 cDNA;   d) a nucleic acid sequence comprising nucleotides 1-981 of the full length A622 cDNA;   e) a nucleic acid sequence comprising nucleotides 1-1160 of the full length A622 cDNA;   f) a nucleic acid sequence comprising nucleotides 1-1179 of the full length A622 cDNA;   g) a nucleic acid sequence comprising nucleotides 354-814 of the full length A622 cDNA;   h) a nucleic acid sequence comprising nucleotides 354-981 of the full length A622 cDNA;   i) a nucleic acid sequence comprising nucleotides 354-1160 of the full length A622 cDNA;   j) a nucleic acid sequence comprising nucleotides 354-1179 of the full length A622 cDNA;   k) a nucleic acid sequence comprising nucleotides 814-981 of the full length A622 cDNA;   l) a nucleic acid sequence comprising nucleotides 814-1160 of the full length A622 cDNA;   m) a nucleic acid sequence comprising nucleotides 814-1179 of the full length A622 cDNA;   n) a nucleic acid sequence comprising nucleotides 981-1160 of the full length A622 cDNA; and   o) a nucleic acid sequence comprising nucleotides 981-1179 of the full length A622 cDNA.   
     
     
         8 . The cured transgenic tobacco of  claim 7 , further comprising a second heterologous nucleic acid molecule that confers suppression of at least one additional gene, wherein said at least one additional gene encodes an enzyme selected from the group consisting of arginine decarboxylase (ADC), methylputrescine oxidase (MPO), NADH dehydrogenase, ornithine decarboxylase (ODC), phosphoribosylanthranilate isomerase (PRAT), putrescine N-methyltransferase (PMT), quinolate phosphoribosyl transferase (QPT), and S-adenosyl-methionine synthetase (SAMS), or any combination thereof. 
     
     
         9 . The cured transgenic tobacco of  claim 7 , wherein said cured transgenic tobacco comprises an amount of nicotine, nornicotine, or a tobacco specific nitrosamine (TSNA) that is less than the amount of nicotine, nornicotine, or said TSNA present in a cured non-transgenic tobacco of the same variety. 
     
     
         10 . The cured transgenic tobacco of  claim 7 , wherein said cured transgenic tobacco comprises an amount of nornicotine that is less than the amount of nornicotine present in a cured non-transgenic tobacco of the same variety and, further wherein said cured transgenic tobacco comprises an amount of nicotine that is commensurate to the amount of nicotine present in a cured non-transgenic tobacco of the same variety. 
     
     
         11 . The cured transgenic tobacco of  claim 10 , wherein said cured transgenic tobacco comprises an amount of nornicotine that is less than or equal to 0.2 mg/g of total biomass. 
     
     
         12 . The cured transgenic tobacco of  claim 11 , wherein said cured transgenic tobacco comprises an amount of nicotine from 0.9-2.0 mg/g of total biomass. 
     
     
         13 . The cured transgenic tobacco of  claim 11 , wherein said cured transgenic tobacco comprises an amount of nornicotine that is from 0.5 ug/g-500 ug/g of total biomass. 
     
     
         14 . The cured transgenic tobacco of  claim 11 , wherein said cured transgenic tobacco comprises an amount of nicotine that is 2.17 to 3.99 mg/g of total biomass and an amount of nornicotine that is less than or equal to 0.00 to 0.06 mg/g of total biomass. 
     
     
         15 . The cured transgenic tobacco of  claim 11 , wherein said cured transgenic tobacco comprises a collective content of TSNAs of less than or equal to 5.0 μg/g, 4.0 μg/g, 3.0 μg/g, 2.0 μg/g, 1.0 μg/g, 0.5 μg/g, or 0.2 μg/g of total biomass. 
     
     
         16 . The cured transgenic tobacco of  claim 7 , wherein said cured transgenic tobacco comprises an amount of nicotine and a collective content of TSNAs that is less than the amount of nicotine and the collective content of TSNAs present in a cured non-transgenic tobacco of the same variety. 
     
     
         17 . The cured transgenic tobacco of  claim 7 , wherein said transgenic tobacco comprises an amount of nicotine that is less than or equal to 1.0 mg/g, 0.6 mg/g, 0.3 mg/g, or 0.05 mg/g of total biomass and a collective content of TSNAs of less than or equal to 5.0 μg/g, 4.0 μg/g, 3.0 μg/g, 2.0 μg/g, 1.0 μg/g, 0.5 μg/g, or 0.2 μg/g of total biomass. 
     
     
         18 . A seed, reproductive tissues, vegetative tissues, biomass, leaves, plant parts, progeny derived from the transgenic tobacco of  claim 7 . 
     
     
         19 . A tobacco product derived from the transgenic tobacco of  claim 7 . 
     
     
         20 . A tobacco product derived from the transgenic tobacco of  claim 8 . 
     
     
         21 . The tobacco product of  claim 19 , further defined as a cigarette. 
     
     
         22 . The tobacco product of  claim 20 , further defined as a cigarette.