Auxinic analogues of indole-3-acetic acid

Abstract

The present invention provides compounds and compositions capable of stimulating plant growth, regeneration of plant cells and tissues, and transformation of plant cells and tissues, comprising mono- and multi-substituted auxinic analogues of indole-3-acetic acid (IAA) comprising substituent groups such as halo, alkyl, alkoxy, acyl, acylamido and acyloxy groups. The invention relates to a method of using such mono- and multi-substituted auxinic analogues of IAA to affect growth, regeneration or transformation in monocotyledonous and dicotyledonous plants, as well as in transgenic plant tissues. The invention also contemplates the use of these auxinic IAA analogues in the presence of other plant growth regulators, such as cytokinin, etc., to enhance plant growth.

1 . A method for generation of callus, shoots, or roots from a plant cell or tissue which comprises the step of contacting said plant cell or plant tissue with an amount of an auxinic compound effective for generation of callus, shoots or roots and having the formula:  
       
         
           
           
               
               
           
         
       
       or salts, esters or amides thereof, wherein R 1 -R 5  are independently selected from the group consisting of a hydrogen, a halogen, an alkyl group, an alkoxy group, an acyl group, an acyloxy group, and an acylamido group, but excluding indole-3-acetic acid and 5-bromoindole-3-acetic acid.  
     
     
         2 . The method of  claim 1  wherein said auxinic compound is a monosubstituted indole-3-acetic acid or salt, ester or amide thereof.  
     
     
         3 . The method of  claim 1  wherein said auxinic compound is a disubstituted indole-3-acetic acid.  
     
     
         4 . The method of  claim 1  wherein in said auxinic compound at least one of R 1 -R 5  is a halogen.  
     
     
         5 . The method of  claim 1  wherein said auxinic compound is 2-fluoroindole-3-acetic acid, 4-fluoroindole-3-acetic acid, 6-fluoroindole-3-acetic acid, 7-fluoroindole-3-acetic acid, 2-bromoindole-3-acetic acid, 4-bromoindole-3-acetic acid, 6-bromoindole-3-acetic acid, 7-bromoindole-3-acetic acid, 2-iodoindole-3-acetic acid, 4-iodoindole-3-acetic acid, 5-iodoindole-3-acetic acid, 6-iodoindole-3-acetic acid, 7-iodoindole-3-acetic acid or salts, esters or amides thereof.  
     
     
         6 . The method of  claim 1  wherein said auxinic compound is 2-fluoroindole-3-acetic acid, 4-fluoroindole-3-acetic acid, 6-fluoroindole-3-acetic acid, 7-fluoroindole-3-acetic acid or salts, esters or amides thereof.  
     
     
         7 . The method of  claim 1  wherein said auxinic compound is 6-fluoroindole-3-acetic acid, 7-fluoroindole-3-acetic acid or salts, esters or amides thereof.  
     
     
         8 . The method of  claim 1  wherein said auxinic compound is 2-bromoindole-3-acetic acid, 4-bromoindole-3-acetic acid, 6-bromoindole-3-acetic acid, 7-bromoindole-3-acetic acid or salts, esters or amides thereof.  
     
     
         9 . The method of  claim 1  wherein said auxinic compound is 2-iodoindole-3-acetic acid, 4-iodoindole-3-acetic acid, 5-iodoindole-3-acetic acid, 6-iodoindole-3-acetic acid, 7-iodoindole-3-acetic acid or salts, esters or amides thereof.  
     
     
         10 . The method of  claim 1  wherein in said auxinic compound one of R 1 -R 5  is an alkyl-group and the remaining R 1 -R 5  groups are hydrogens.  
     
     
         11 . The method of  claim 1  wherein said auxinic compound is 7-ethylindole-3-acetic acid, 5-ethylindole-3-acetic acid, or salts, esters or amides thereof.  
     
     
         12 . The method of  claim 1  wherein in said auxinic compound one of R 1 -R 5  is an alkoxy- group and the remaining R 1 -R 5  groups are hydrogens.  
     
     
         13 . The method of  claim 1  wherein one of said R 1 -R 5  groups is a methoxy group.  
     
     
         14 . The method of  claim 1  wherein said auxinic compound is 5-methoxyindole-3-acetic acid or salts, esters or amides thereof.  
     
     
         15 . The method of  claim 1  wherein said plant cell or plant tissue comprises foreign DNA.  
     
     
         16 . The method of  claim 1  wherein said plant cell or tissue is that of a hard-to-regenerate plant.  
     
     
         17 . The method of  claim 1  wherein said plant cell or tissue is that of a woody plant or a monocotyledonous plant.  
     
     
         18 . The method of  claim 1  wherein said plant cell or tissue is a cell or tissue of a cassava plant.  
     
     
         19 . A method for regeneration of a plant from a plant cell or plant tissue which comprises the steps of: 
 (a) contacting said plant cell or plant tissue with an amount of an auxinic compound effective for regeneration of roots and    (b) contacting said plant cell or plant tissue with a combination of said auxinic compound and a cytokinin in a combined amount effective for the regeneration of shoots from said plant cell or plant tissue wherein said auxinic compound has the formula:                          or salts, esters and amides thereof, wherein R 1 -R 5  are selected from the group consisting of halogens.    
     
     
         20 . The method of  claim 19  wherein said auxinic compound is a monosubstituted indole-3-acetic acid or salt, ester or amide thereof.  
     
     
         21 . The method of  claim 20  wherein in said auxinic compound one of R 1 -R 5  is a bromine, a fluorine or an iodine.  
     
     
         22 . The method of  claim 20  wherein in said auxinic compound one of R 1 -R 5  is a chlorine.  
     
     
         23 . The method of  claim 19  wherein said auxinic compound is a disubstituted indole-3-acetic acid or salt, ester or amide thereof.  
     
     
         24 . The method of  claim 23  wherein in said auxinic compound at least one of R 1 -R 5  is a bromine or a fluorine.  
     
     
         25 . The method of  claim 23  wherein in said auxinic compound at least one of R 1 -R 5  is a chlorine.  
     
     
         26 . A method for regeneration of a plant from a plant cell or plant tissue which comprises the steps of: 
 (a) contacting said plant cell or plant tissue with an amount of an auxinic compound effective for regeneration of roots and    (b) contacting said plant cell or plant tissue with a combination of said auxinic compound and a cytokinin in a combined amount effective for the regeneration of shoots from said plant cell or plant tissue wherein said auxinic compound has the formula:                          or salts, esters and amides thereof, wherein one of R 1 -R 5  is an alkyl group having from one to four carbon atoms and the remaining R 1 -R 5  groups are hydrogens.    
     
     
         27 . The method of  claim 26  wherein one of R 1 -R 5  is an ethyl group.  
     
     
         28 . The method of  claim 1  for generation of roots from a potato cell or tissue which comprises the step of contacting said potato cell or tissue with an amount of 7-ethyl indole-3-acetic acid effective for generation of roots.  
     
     
         29 . A method for regeneration of a plant from a plant cell or plant tissue which comprises the steps of: 
 (a) contacting said plant cell or plant tissue with an amount of an auxinic compound effective for regeneration of roots and    (b) contacting said plant cell or plant tissue with a combination of said auxinic compound and a cytokinin in a combined amount effective for the regeneration of shoots from said plant cell or plant tissue wherein said auxinic compound has the formula:                          or salts, esters and amides thereof, wherein one of R 1 -R 5  is an alkoxy group and having from one to four carbon atoms and the remaining R 1 -R 5  groups are hydrogens.    
     
     
         30 . The method of  claim 29  wherein one of R 1 -R 5  is a methoxy group.  
     
     
         31 . The method of  claim 30  wherein said auxinic compound is 5-methoxyindole-3-acetic acid or salts, esters or amides thereof.  
     
     
         32 . A method for regeneration of a plant from a plant cell or plant tissue which comprises the steps of: 
 (a) contacting said plant cell or plant tissue with an amount of an auxinic compound effective for regeneration of roots and    (b) contacting said plant cell or plant tissue with a combination of said auxinic compound and a cytokinin in a combined amount effective for regeneration of shoots from said plant cell or plant tissue wherein said auxinic compound has the formula:                          or salts, esters or amides thereof, wherein R 1 -R 5  are independently selected from the group consisting of a hydrogen, a halogen, an alkyl group, an alkoxy group, an acyl group, an acyloxy group, and an acylamido group, but excluding indole-3-acetic acid and 5-bromoindole-3-acetic acid wherein the plant cell or tissue is that of a hard-to-regenerate plant.    
     
     
         33 . The method of  claim 32  wherein said plant cell or tissue is that of a woody plant or a monocotyledonous plant.  
     
     
         34 . The method of  claim 33  wherein said plant cell or tissue is a cell or tissue of a cassava plant.  
     
     
         35 . The method of  claim 34  wherein in said auxinic compound R 3  or R 5  is a fluorine,  
     
     
         36 . The method of  claim 35  wherein said auxinic compound is 5-fluoro-3-indoleacetic acid or salts, esters or amides thereof.  
     
     
         37 . A composition for generation of callus, shoots or roots from a plant cell or tissue which comprises an amount of an auxinic compound effective for generating callus, shoots or roots and having the formula:  
       
         
           
           
               
               
           
         
       
       or salts, esters and amides thereof, wherein R 1 -R 5  are independently selected from the group consisting of a hydrogen, a halogen, an alkyl group, an alkoxy group, an acyl group, an acyloxy group, and an acylamido group, but excluding indole-3-acetic acid and 5-bromoindole-3-acetic acid.  
     
     
         38 . The composition of  claim 37  wherein said auxinic compound, said alkyl group, said alkoxy group, said acyl group, said acyloxy group and an acylamido group have 1-10 carbon atoms.  
     
     
         39 . The composition of  claim 38  wherein in said auxinic compound at least one of R 1 -R 5  is an alkyl group.  
     
     
         40 . The composition of  claim 39  wherein in said auxinic compound R 3  or R 5  is an alkyl group having from one to four carbon atoms and R 1 , R 2 , and R 4  are hydrogens.  
     
     
         41 . The composition of  claim 37  wherein in said auxinic compound at least one of R 1 -R 5  is a halogen.  
     
     
         42 . The composition of  claim 37  wherein said auxinic compound is 2-fluoroindole-3-acetic acid, 4-fluoroindole-3-acetic acid, 6-fluoroindole-3-acetic acid, 7-fluoroindole-3-acetic acid, 2-bromoindole-3-acetic acid, 4-bromoindole-3-acetic acid, 6-bromoindole-3-acetic acid, 7-bromoindole-3-acetic acid, 2-iodoindole-3-acetic acid, 4-iodoindole-3-acetic acid, 5-iodoindole-3-acetic acid, 6-iodoindole-3-acetic acid, 7-iodoindole-3-acetic acid, 5-ethylindole-3-acetic acid, 7-ethylindole-3-acetic acid or salts, esters or amides thereof.  
     
     
         43 . The composition of  claim 37  wherein said at least one of R 1 -R 5  is an acyl group, an acyloxy group, or an acylamido group.  
     
     
         44 . The composition of  claim 37  further comprising a growth-affecting amount of a cytokinin.  
     
     
         45 . An auxinic compound having the formula:  
       
         
           
           
               
               
           
         
       
       or salts, esters or amides thereof, wherein R 1 -R 5  are independently selected from the group consisting of a hydrogen, a halogen, an alkyl-group, an alkoxy-group, an acyl-group, an acyloxy-group, and an acylamido-group, and wherein at least one of R 1 -R 5  is an alkoxy-group, an acyl-group, an acyloxy-group or an acylamido-group with the exception that the compound is not 5-methoxyindole-3-acetic acid.  
     
     
         46 . An auxinic compound having the formula:  
       
         
           
           
               
               
           
         
       
       or salts, esters or amides thereof, wherein R 1 -R 5  are independently selected from the group consisting of a hydrogen, a fluorine, a bromine, an iodine, an alkyl group, an alkoxy-group, an acyl-group, an acyloxy-group, and an acylamido-group, wherein at least one of R 1 -R 5  is an alkoxy-group, an acyl-group, an acyloxy-group or an acylamido-group and with the exception that the auxinic compound is not 5-bromoindole-3-acetic acid, 7-bromoindole-3-acetic acid, 5-fluoroindole-3-acetic acid, 2-methylindole-3-acetic acid, 5-methylindole-3-acetic acid, or 5-methoxyindole-3-acetic acid.