Tomatoes having reduced polygalacturonase activity caused by non-transgenic mutations in the polygalacturonase gene

Abstract

A series of independent non-transgenic mutations found in the fruit PG gene of tomato; tomato plants having these mutations in their fruit PG gene; and a method of creating and identifying similar and/or additional mutations in the PG gene by screening pooled and/or individual tomato plants. The tomato plants of the present invention exhibit reduced PG enzyme activity and fruit that soften more slowly post harvest without having the inclusion of foreign nucleic acids in their genomes.

I claim:  
     
         1 . A tomato plant, tomato fruits, seeds, plant parts and progeny thereof having reduced fruit polygalacturonase enzyme activity compared to the wild type tomato plants wherein the reduced fruit polygalacturonase enzyme activity is caused by a non-transgenic mutation in a fruit polygalacturonase gene.  
     
     
         2 . Food and food products incorporating a tomato fruit of  claim 1 .  
     
     
         3 . Pollen from the tomato plant of  claim 1 .  
     
     
         4 . A tomato plant having tomato fruits which soften slower post harvest compared to wild type tomato fruits due to an altered polygalacturonase enzyme.  
     
     
         5 . Tomato fruits, seeds, plant parts and progeny of the tomato plant of  claim 4 .  
     
     
         6 . Pollen from the tomato plant of  claim 4 .  
     
     
         7 . Food and food products incorporating a tomato fruit of  claim 4 .  
     
     
         8 . The tomato plant of  claim 4  having a non-transgenic mutation in a fruit polygalacturonase gene.  
     
     
         9 . Tomato fruits, seeds, plant parts and progeny of the tomato plant of  claim 8 .  
     
     
         10 . Pollen from the tomato plant of  claim 8 .  
     
     
         11 . Food and food products incorporating a tomato of  claim 8 .  
     
     
         12 . An endogenous fruit polygalacturonase gene having substantial homology to SEQ. I.D. No. 1 and having a non-transgenic mutation within the endogenous fruit polygalacturonase gene.  
     
     
         13 . The endogenous fruit polygalacturonase gene of  claim 12  wherein the non-transgenic mutation occurs around nucleotide 1969.  
     
     
         14 . A tomato plant containing the endogenous fruit polygalacturonase gene of  claim 13 .  
     
     
         15 . Tomato fruits, seeds, pollen, plant parts, and progeny of the tomato plant of  claim 14 .  
     
     
         16 . Food and food products incorporating the fruit of the tomato plant of  claim 14 .  
     
     
         17 . The endogenous fruit polygalacturonase gene of  claim 12  wherein the non-transgenic mutation creates a change in at least amino acid 178 of the fruit polygalacturonase enzyme expressed from the fruit polygalacturonase gene.  
     
     
         18 . A polygalacturonase enzyme expressed from the endogenous fruit polygalacturonase gene of  claim 17 .  
     
     
         19 . The polygalacturonase enzyme of  claim 18  having an arginine at amino acid 178.  
     
     
         20 . The endogenous fruit polygalacturonase gene of  claim 12  wherein the non-transgenic mutation occurs around nucleotide 2940.  
     
     
         21 . A tomato plant containing the endogenous fruit polygalacturonase gene of  claim 20 .  
     
     
         22 . Tomato fruits, seeds, pollen, plant parts, and progeny of the tomato plant of  claim 21 .  
     
     
         23 . Food and food products incorporating the fruit of the tomato plant of  claim 21 .  
     
     
         24 . The endogenous fruit polygalacturonase gene of  claim 12  wherein the non-transgenic mutation creates a change in at least amino acid 252 of the fruit polygalacturonase enzyme expressed from the fruit polygalacturonase gene.  
     
     
         25 . A polygalacturonase enzyme expressed from the endogenous fruit polygalacturonase gene of  claim 24 .  
     
     
         26 . The polygalacturonase enzyme of  claim 25  having a glutamine at amino acid 252.  
     
     
         27 . A tomato plant having reduced fruit polygalacturonase enzyme activity compared to the wild type tomato plants created by the steps of: 
 a. obtaining plant material from a parent tomato plant;    b. inducing at least one mutation in at least one copy of a fruit polygalacturonase gene of the plant material by treating the plant material with a mutagen to create mutagenized plant material;    c. culturing the mutagenized plant material to produce progeny tomato plants;    d. analyzing progeny tomato plants to detect at least one mutation in at least one copy of a fruit polygalacturonase gene;    e. selecting progeny tomato plants that have reduced fruit polygalacturonase enzyme activity compared to the parent tomato plant; and    f. repeating the cycle of culturing the progeny tomato plants to produce additional progeny plants having reduced fruit polygalacturonase enzyme activity.    
     
     
         28 . The method of  claim 27  wherein the plant material is selected from the group consisting of seeds, pollen, plant cells, or plant tissue.  
     
     
         29 . The method of  claim 27  wherein the mutagen is ethyl methanesulfonate.  
     
     
         30 . The method of  claim 29  wherein the concentration of ethyl methanesulfonate used is from about 0.4 to about 1.2%.  
     
     
         31 . The tomato plant of  claim 27  wherein the steps to create the tomato plant further included analyzing the progeny tomato plants by 
 a. isolating genomic DNA from the progeny tomato plants; and  
 b. amplifying segments of the polygalacturonase gene in the isolated genomic DNA using primers specific to the polygalacturonase gene or to the DNA sequences adjacent to the polygalacturonase gene.  
 
     
     
         32 . The tomato plant of  claim 31  wherein at least one primer has a sequence substantially homologous to a sequence as shown in the group consisting of SEQ. I.D. Nos. 3 through 46.  
     
     
         33 . Tomato fruit, seeds, pollen, plant parts or progeny of the tomato plant of  claim 27 .  
     
     
         34 . Food and food products incorporating the fruit of a tomato plant of  claim 27.