Method of producing transgenic plants having improved amino acid composition and improved yielding

Abstract

The object of the present invention is to provide transgenic plants which accumulate free amino acids, particularly at least one amino acid selected from among glutamic acid, asparagine, aspartic acid, serine, threonine, alanine and histidine accumulated in a large amount, in the edible parts thereof, and a method of producing them are provided. The other object of the present invention is to provide a method of increasing the yielding of potato and to provide a transgenic potato of which yielding can be increased. In the present invention, a sequence encoding glutamate dehydrogenase (GDH) gene is introduced into a plant together with a suitable regulatory sequence to express it in a plant cell, and thereby the GDH gene is excessively expressed.

1 - 19 . (canceled)  
     
     
         20 . A method of producing a transgenic potato increased in the total weight of the tuber parts compared to a untransfonned potato cultured under the same conditions, which comprises the step of transfonring a plant with a genetic construct causing excessive expression of a glutamate dehydrogenase (GDH) gene, and selecting or identifying the transformed plant based on a character imparted by a marker gene connected to the genetic construct, screening the transformed plant in which the total weight of the tuber parts is increased and selecting the transformed plant in which the total weight of the tuber parts is increased.  
     
     
         21 . The method according to  claim 20 , wherein the total weight of the tuber parts of the potato exhibits 1.5-fold or more increase compared to a untransformed potato cultured under the same conditions.  
     
     
         22 . The method according to  claim 20 , wherein the genetic construct contains a gene encoding GDH functionally connected to a powerful constitutive promoter.  
     
     
         23 . The method according to  claim 20 , wherein the constitutive promoter is CaMV35S promoter.  
     
     
         24 . The method according to  claim 20 , wherein the genetic construct contains  Aspergillus nidulans  NADP-GDH gene.  
     
     
         25 . The method according to  claim 20 , wherein GDH contains a transit peptide for mitochondria.