Methods for Increasing the Resistance of Plants to Hypoxic Conditions

Abstract

Methods are provided for increasing the resistance of plants to hypoxic or anoxic conditions. Such methods may be applied to increase the penetrance of plant roots in the growth medium or into soil. The methods according to the invention may include providing plants with a stress tolerance gene. Similar effects can be obtained by applying chemical compounds, including neonicotinoid compounds, to the plants.

1 . A method for increasing the tolerance of a plant cell or plant to hypoxic or anoxic conditions, comprising the step of:
 a) providing a stress tolerance enhancing transgene to said plant cell or cells of said plant; wherein said stress tolerance enhancing transgene is
 i. a stress tolerance enhancing transgene capable of reducing the expression of plant endogenous PARP genes; 
 ii. a stress tolerance enhancing transgene capable of reducing the expression of plant endogenous PARG genes; 
 iii. a stress tolerance enhancing transgene coding for a plant-functional enzyme of the nicotinamide adenine dinucleotide salvage synthesis pathway selected from nicotinamidase, nicotinate phosphoribosyltransferase, nicotinic acid mononucleotide adenyl transferase or nicotinamide adenine dinucleotide synthetase. 
   
     
     
         2 . A method for increasing the penetrance of roots of a plant into a growth medium, comprising the step of:
 a) providing a stress tolerance enhancing transgene to said plant cell or cells of said plant; wherein said stress tolerance enhancing transgene is
 i. a stress tolerance enhancing transgene capable of reducing the expression of plant endogenous PARP genes; 
 ii. a stress tolerance enhancing transgene capable of reducing the expression of plant endogenous PARG genes; or 
 iii. a stress tolerance enhancing transgene coding for a plant-functional enzyme of the nicotinamide adenine dinucleotide salvage synthesis pathway selected from nicotinamidase, nicotinate phosphoribosyltransferase, nicotinic acid mononucleotide adenyl transferase or nicotinamide adenine dinucleotide synthetase. 
   
     
     
         3 . The method according to  claim 1 , wherein said stress tolerance enhancing transgene codes for a PARP inhibitory RNA molecule. 
     
     
         4 . The method according to  claim 3 , wherein said transgene comprises the following operably linked DNA fragments:
 a) a plant expressible promoter;   b) a DNA region coding for a PARP inhibitory RNA molecule comprising at least 19 out of 20 consecutive nucleotides from the nucleotide sequence of SEQ ID No 1, the nucleotide sequence of SEQ ID No 2, the nucleotide sequence of SEQ ID No 3, the nucleotide sequence of SEQ ID No 4, the nucleotide sequence of SEQ ID No 5, or the nucleotide sequence of SEQ ID No 6; and   c) a transcription termination and polyadenylation DNA region.   
     
     
         5 . The method according to  claim 3 , wherein said transgene comprises the following operably linked DNA fragments:
 a) a plant expressible promoter;   b) a DNA region coding for a PARP inhibitory RNA molecule comprising at least 19 out of 20 consecutive nucleotides from the complement of the nucleotide sequence of SEQ ID No 1, the nucleotide sequence of SEQ ID No 2, the nucleotide sequence of SEQ ID No 3, the nucleotide sequence of SEQ ID No 4, the nucleotide sequence of SEQ ID No 5, or the nucleotide sequence of SEQ ID No 6; and   c) a transcription termination and polyadenylation DNA region.   
     
     
         6 . The method according to  claim 3 , wherein said transgene comprises the following operably linked DNA fragments:
 a) a plant expressible promoter;   b) a DNA region coding for a PARP inhibitory RNA molecule, said RNA molecule comprising:
 i. a sense nucleotide sequence comprising at least 19 out of 20 consecutive nucleotides from the nucleotide sequence of SEQ ID No 1, the nucleotide sequence of SEQ ID No 2, the nucleotide sequence of SEQ ID No 3, the nucleotide sequence of SEQ ID No 4, the nucleotide sequence of SEQ ID No 5, or the nucleotide sequence of SEQ ID No 6; and 
 ii. an antisense nucleotide sequence comprising a nucleotide sequence complementary to said at least 20 consecutive nucleotides in said sense nucleotide sequence 
   wherein said sense and antisense nucleotide sequence are capable of forming a double stranded RNA region; and   c) a transcription termination and polyadenylation DNA region.   
     
     
         7 . The method according to  claim 6 , wherein said antisense nucleotide sequence has about 95% sequence identity or is identical to said sense nucleotide sequence. 
     
     
         8 . The method according to  claim 1 , wherein said transgene codes for a ParG inhibitory RNA molecule. 
     
     
         9 . The method according to  claim 8 , wherein said transgene comprises the following operably linked DNA fragments:
 a) a plant expressible promoter;   b) a DNA region coding for a PARG inhibitory RNA molecule comprising at least 19 out of 20 consecutive nucleotides from the nucleotide sequence of SEQ ID No 7, the nucleotide sequence of SEQ ID No 8, the nucleotide sequence of SEQ ID No 9 or the nucleotide sequence of SEQ ID No 10; and   c) a transcription termination and polyadenylation DNA region.   
     
     
         10 . The method according to  claim 8 , wherein said transgene comprises the following operably linked DNA fragments:
 a) a plant expressible promoter;   b) a DNA region coding for a PARG inhibitory RNA molecule comprising at least 19 out of 20 consecutive nucleotides from the complement of the nucleotide sequence of SEQ ID No 7, the nucleotide sequence of SEQ ID No 8, the nucleotide sequence of SEQ ID No 9, or the nucleotide sequence of SEQ ID No 10; and   c) a transcription termination and polyadenylation DNA region.   
     
     
         11 . The method according to  claim 8 , wherein said transgene comprises the following operably linked DNA fragments:
 a) a plant expressible promoter;   b) a DNA region coding for a PARG inhibitory RNA molecule, said RNA molecule comprising:
 i. a sense nucleotide sequence comprising at least 19 out of 20 consecutive nucleotides from the nucleotide sequence of SEQ ID No 7, the nucleotide sequence of SEQ ID No 8, the nucleotide sequence of SEQ ID No 9 or the nucleotide sequence of SEQ ID No 10; and 
 ii. an antisense nucleotide sequence comprising a nucleotide sequence complementary to said at least 20 consecutive nucleotides in said sense nucleotide sequence 
   wherein said sense and antisense nucleotide sequence are capable of forming a double stranded RNA region; and   c) a transcription termination and polyadenylation DNA region.   
     
     
         12 . The method according to  claim 11 , wherein said antisense nucleotide sequence has about 95% sequence identity or is identical to said sense nucleotide sequence. 
     
     
         13 . The method according to  claim 1 , wherein said transgene codes for a plant-functional enzyme of the nicotinamide adenine dinucleotide salvage synthesis pathway selected from nicotinamidase, nicotinate phosphoribosyltransferase, nicotinic acid mononucleotide adenyl transferase or nicotinamide adenine dinucleotide synthetase. 
     
     
         14 . The method according to  claim 13 , wherein said transgene comprises a the nucleotide sequence of SEQ ID No. 11, the nucleotide sequence of SEQ ID No. 12, the nucleotide sequence of SEQ ID No. 13, the nucleotide sequence of SEQ ID No. 14, the nucleotide sequence of SEQ ID No. 15, the nucleotide sequence of SEQ ID No. 16, the nucleotide sequence of SEQ ID No. 17, the nucleotide sequence of SEQ ID No. 18, the nucleotide sequence of SEQ ID No. 19, the nucleotide sequence of SEQ ID No. 20, the nucleotide sequence of SEQ ID No. 21 or the nucleotide sequence of SEQ ID No. 22. 
     
     
         15 . The method according to  claim 1 , comprising the further step of applying an effective amount of a compound of formula (I) 
       
         
           
           
               
               
           
         
         wherein 
         Het represents a heterocycle which is either mono- or polysubstituted by fluorine, chlorine, methyl or ethyl, wherein said heterocycle is
 pyrid-3-yl, pyrid-5-yl, 3-pyridinio, 1-oxido-5-pyridinio, 1-oxido-5-pyridinio, tetra-hydrofuran-3-yl, or thiazol-5-yl, 
 
         A represents C 1 -C 6 -alkyl, —N(R 1 )(R 2 ) or S(R 2 ),
 in which 
 R 1  represents hydrogen, C 1 -C 6 -alkyl, phenyl-C 1 -C 4 -alkyl, C 3 -C 6 -cycloalkyl, C 2 -C 6 -alkenyl or C 2 -C 6 -alkynyl, and 
 R 2  represents C 1 -C 6 -alkyl, C 2 -C 6 -alkenyl, C 2 -C 6 -alkynyl, —C(═O)—CH 3  or benzyl, 
 
         R represents hydrogen, C 1 -C 6 -alkyl, C 2 -C 6 -alkenyl, C 2 -C 6 -alkynyl, —C(═O)—CH 3  or benzyl or together with R 2  represents the groups below:
 —CH 2 —CH 2 —, —CH 2 —CH 2 —CH 2 —, —CH 2 —O—CH 2 —, —CH 2 —S—CH 2 —, —CH 2 —NH—CH 2 —, or —CH 2 —N(CH 1 )—CH 2 —, and 
 
         X represents N—NO 2 , N—CN or CH—NO 2    
         on said plant or on its locus, or on seeds of said plant. 
       
     
     
         16 . The method according to  claim 15 , wherein said heterocycle represented by Het of said compound of formula (I) is a pyrid-3-yl heterocycle substituted by chlorine. 
     
     
         17 . The method of  claim 16 , wherein said compound of formula (I) is imidacloprid or thiacloprid. 
     
     
         18 - 29 . (canceled) 
     
     
         30 . A method for increasing the protrusion of the roots of a plant into a growth medium comprising
 a) transforming said plant with a foreign DNA comprising a stress tolerance enhancing transgene or a variant of an endogenous gene corresponding to such stress tolerance enhancing transgene, and/or   b) applying an effective amount of 6-chloronicotinic acid or a compound of formula (I)   
       
         
           
           
               
               
           
         
         
           wherein 
           Het represents a heterocycle which is either mono- or polysubstituted by fluorine, chlorine, methyl or ethyl, wherein said heterocycle is
 pyrid-3-yl, pyrid-5-yl, 3-pyridinio, 1-oxido-5-pyridinio, 1-oxido-5-pyridinio, tetra-hydrofuran-3-yl, or thiazol-5-yl, 
 
           A represents C 1 -C 6 -alkyl, —N(R 1 )(R 2 ) or S(R 2 ),
 in which 
 R 1  represents hydrogen, C 1 -C 6 -alkyl, phenyl-C 1 -C 4 -alkyl, C 3 -C 6 -cycloalkyl, C 2 -C 6 -alkenyl or C 2 -C 6 -alkynyl, and 
 R 2  represents C 1 -C 6 -alkyl, C 2 -C 6 -alkenyl, C 2 -C 6 -alkynyl, —C(═O)—CH 3  or benzyl, 
 
           R represents hydrogen, C 1 -C 6 -alkyl, C 2 -C 6 -alkenyl, C 2 -C 6 -alkynyl, —C(═O)—CH 3  or benzyl or together with R 2  represents the groups below:
 —CH 2 —CH 2 —, —CH 2 —CH 2 —CH 2 —, —CH 2 —O—CH 2 —, —CH 2 —S—CH 2 —, —CH 2 —NH—CH 2 —, or —CH 2 —N(CH 3 )—CH 2 —, and 
 
           X represents N—NO 2 , N—CN or CH—NO 2 . 
         
       
     
     
         31 . A method for increasing the tolerance of a plant to hypoxic or anoxic conditions comprising
 a) transforming a plant with a foreign DNA comprising a stress tolerance enhancing transgene or a variant of an endogenous gene corresponding to such stress tolerance enhancing transgene, and/or   b) applying an effective amount of 6-chloronicotinic acid or a compound of formula (I)   
       
         
           
           
               
               
           
         
         
           wherein 
           Het represents a heterocycle which is either mono- or polysubstituted by fluorine, chlorine, methyl or ethyl, wherein said heterocycle is
 pyrid-3-yl, pyrid-5-yl, 3-pyridinio, 1-oxido-5-pyridinio, 1-oxido-5-pyridinio, tetra-hydrofuran-3-yl, or thiazol-5-yl, 
 
           A represents C 1 -C 6 -alkyl, —N(R 1 )(R 2 ) or S(R 2 ),
 in which 
 R 1  represents hydrogen, C 1 -C 6 -alkyl, phenyl-C 1 -C 4 -alkyl, C 3 -C 6 -cycloalkyl, C 2 -C 6 -alkenyl or C 2 -C 6 -alkynyl, and 
 R 2  represents C 1 -C 6 -alkyl, C 2 -C 6 -alkenyl, C 2 -C 6 -alkynyl, —C(═O)—CH 3  or benzyl, 
 
           R represents hydrogen, C 1 -C 6 -alkyl, C 2 -C 6 -alkenyl, C 2 -C 6 -alkynyl, —C(═O)—CH 3  or benzyl or together with R 2  represents the groups below:
 —CH 2 —CH 2 —, —CH 2 —CH 2 —CH 2 —, —CH 2 —O—CH 2 —, —CH 2 —S—CH 2 —, —CH 2 —NH—CH 2 —, or —CH 2 —N(CH 1 )—CH 2 —, and 
 
           X represents N—NO 2 , N—CN or CH—NO 2 . 
         
       
     
     
         32 . The method of  claim 31 , wherein said hypoxic or anoxic conditions are brought on said plant by exposure to waterlogging, submergence, or flooding.