Active substances for increasing the stress defense in plants to abiotic stress, and methods of finding them

Abstract

The invention relates to a method of finding compounds which increase the tolerance of plants to abiotic stress factors acting on this plant, such as, for example, temperature (such as chill, frost or heat), water (such as dryness, drought or anoxia), or the chemical load (such as lack of or excess of mineral salts, heavy metals, gaseous noxious substances) by increasing the expression of plant-endogenous proteins, and to the use of these compounds for increasing the tolerance in plants to abiotic stress factors.

1 . A method of finding a compound which increases the tolerance to abiotic stress factors in plants, where the increase in the transcription or expression of individual plant-endogenous genes or of a plurality of plant-endogenous genes is regarded as proof for the induction.  
   
   
       2 . The method as claimed in  claim 1 , wherein the plant-endogenous genes are selected from the group of genes coding for proteins from the group of the cytochrome oxidases, glycosyltransferases, uricases, peptidases, various membrane proteins, amidohydrolases, late embryogenesis abundant proteins, and various general stress proteins.  
   
   
       3 . The method according to  claim 1 , which comprises: 
 a) exposing test plants to one or more abiotic stress factors,    b) bringing control plants, under otherwise identical conditions like the test plants of a), additionally into contact with a test compound, be it in the form of dressed seed material or be it by spraying with a particular development stage or else by uptake via the roots,    c) extracting RNA from the test plants and the control plants,    d) either labeling the RNA directly with a radiolabel or with a cold label, or else labeling the RNA with a radiolabel or a cold label while simultaneously transcribing it enzymatically into the corresponding cDNA, or else transcribing the resulting, unlabeled cDNA enzymatically into a corresponding radiolabeled or cold-labeled cRNA,    e) hybridizing a DNA microarray which comprises plant DNA sequences with the substances obtained in step d),    f) generating expression profiles of the genes for the expression of different stress proteins by comparing the plants tested in a) and b),    g) quantitatively determining the expression differentials measured in f), and    h) carrying out the cluster analysis of the expression profiles assigned in g) for a final classification.    
   
   
       4 . The method as claimed in  claim 3 , where, in the case of the intended increase of the tolerance under heat stress conditions, the expression of the genes of the cytochrome oxidases, such as the cytochrome oxidase P450, glycosyltransferases, uricases, peptidases, various membrane proteins, amidohydrolases, is compared for heat-stressed and non-heat-stressed plants.  
   
   
       5 . The method as claimed in  claim 4 , wherein the expression of the genes of the N-carbamyl-L-amino acid amidohydrolase, the serine carboxypeptidase, the uricase II (E.C.1.7.3.3) and the glycosyltransferase is compared for heat-stressed and non-heat-stressed plants.  
   
   
       6 . The method according to  claim 4 , wherein the expression profile of one or more of the abovementioned genes is increased by a factor of 1.5 to 30, preferably 1.5 to 20, especially preferably 1.5 to 10, very especially preferably 1.5 to 5.  
   
   
       7 . The method according to  claim 3 , where, in the case of the intended increase of the tolerance under drought stress conditions, the expression of the late embryogenesis abundant proteins, of the universal stress protein, of the non-symbiotic hemoglobin (Zm.485.1.A1_at), of the protein addressed as “Zm.818.2.A1_a at” (signature according to maize genome array from Affymetrix) and of the protein addressed as “Zm.18682.1.A1_s_at” (signature according to maize genome array from Affymetrix) of drought-stressed and non-drought-stressed plants is compared.  
   
   
       8 . The method according to  claim 7 , wherein the expression of the genes of the universal stress protein (Zm.818,1.A1_at), of the non-symbiotic hemoglobin (Zm.485.1.A1_at) of the protein addressed as “Zm.818.2.A1_a_at” (signature according to maize genome array from Affymetrix) and of the protein addressed as “Zm.18682.1.A1_s_at” (signature according to maize genome array from Affymetrix) of drought-stressed and non-drought-stressed plants is compared.  
   
   
       9 . The method according to  claim 7 , wherein the expression profile of one or more of the abovementioned genes is increased by a factor of 1.5 to 30, preferably 1.5 to 20, especially preferably 1.5 to 10, very especially 1.5 to 8.  
   
   
       10 . The use of one or more compounds which are identified with the aid of a method as claimed in  claim 1  and/or compounds which are already known as safeners, for increasing the tolerance to abiotic stress factors, for increasing the yield, for extending the vegetation period, for making possible an earlier sowing date, for increasing the quality, or for use in plant breeding using otherwise less vital inbred lines.  
   
   
       11 . The use of compounds as claimed in  claim 10  whose use as safeners is already known in crop protection, selected from the group consisting of mefenpyr-diethyl, isoxadifen-ethyl, chloquintocet-mexyl, fenclorim, dymron and 4-cyclopropylaminocarbonyl-N-(2-methoxybenzoyl)benzenesulfonamide.  
   
   
       12 . The use of compounds as claimed in  claim 11  whose use as safeners is already known in crop protection, selected from the group consisting of mefenpyr-diethyl and 4-cyclopropylaminocarbonyl-N-(2-methoxybenzoyl)benzenesulfonamide.  
   
   
       13 . The use of compounds as claimed in  claim 10  for increasing the tolerance to abiotic stress factors in the crop plants maize, wheat, barley, rye, oats, rice, soya, sunflower, oilseed rape and sugar beet.  
   
   
       14 . A method of increasing the yield in crops of useful plants, which comprises treating the useful plants by seed dressing, by foliar sprays or by soil application, with one or more compounds which have been identified by a method as claimed in  claim 1  and/or compounds which are already known as safeners in crop protection.  
   
   
       15 . A method of extending the vegetation period in crops of useful plants, which comprises treating the useful plants by seed dressing, by foliar sprays or by soil application, with one or more compounds which have been identified by a method as claimed in  claim 1  and/or compounds which are already known as safeners in crop protection.  
   
   
       16 . A method of making possible an earlier sowing date in crops of useful plants, which comprises treating the useful plants by seed dressing, by foliar sprays or by soil application, with one or more compounds which have been identified by a method as claimed in  claim 1  and/or compounds which are already known as safeners in crop protection.  
   
   
       17 . A method of increasing the quality in crops of useful plants, which comprises treating the useful plants by seed dressing, by foliar sprays or by soil application, with one or more compounds which have been identified by a method as claimed in  claim 1  and/or compounds which are already known as safeners in crop protection.