Transgenic Plant for Producing Polyglutamic Acid

1 . A method for preparing a transgenic plant for producing polyglutamic acid comprising:

introducing a nucleic acid encoding the polyglutamic acid synthase A (pgsA), a nucleic acid encoding the polyglutamic acid synthase B (pgsB) and a nucleic acid encoding the polyglutamic acid synthase C (pgsC) into a plant.

2 . The method of claim 1 wherein

the polyglutamic acid synthase A has the amino acid sequence of SEQ ID NO:1 or an amino acid sequence wherein one or more amino acid residues are deleted from, added to or substituted in SEQ ID NO:1, the polyglutamic acid synthase B has the amino acid sequence of SEQ ID NO:3 or an amino acid sequence wherein one or more amino acid residues are deleted from, added to or substituted in SEQ ID NO:3, the polyglutamic acid synthase C has the amino acid sequence of SEQ ID NO:5 or an amino acid sequence wherein one or more amino acid residues are deleted from, added to or substituted in SEQ ID NO:5; and

three types of the polyglutamic acid synthase, A, B and C, together, have the function to produce polyglutamic acid.

3 . The method of claim 1 wherein

the polyglutamic acid synthase A has the amino acid sequence of SEQ ID NO:1 or an amino acid sequence which is at least 70% identical with SEQ ID NO:1, the polyglutamic acid synthase B has the amino acid sequence of SEQ ID NO:3 or an amino acid sequence which is at least 70% identical with SEQ ID NO:3, and the polyglutamic acid synthase C has the amino acid sequence of SEQ ID NO:5 or an amino acid sequence which is at least 70% identical with SEQ ID NO:5; and

three types of the polyglutamic acid synthase, A, B and C, together, have the function to produce polyglutamic acid.

4 . The method of claim 1 wherein the plant is infected with Agrobacterium containing a vector inserted with one or more nucleic acids selected from a nucleic acid encoding the polyglutamic acid synthase A (pgsA), a nucleic acid encoding the polyglutamic acid synthase B (pgsB) and a nucleic acid encoding the polyglutamic acid synthase C (pgsC) to introduce the nucleic acids into the plant.

5 . The method of claim 4 wherein introduction of the three types of the nucleic acids, pgsA, pgsB and pgsC is performed by any one of the following steps a)-c):

a) infecting the plant with Agrobacterium containing a single vector inserted with three types of nucleic acids, pgsA, pgsB and pgsC;

b) infecting the plant with three types of Agrobacterium each of them containing a distinct vector inserted with pgsA, pgsB or pgsC, respectively; or

c) infecting the plant with one or two types of Agrobacterium each of them containing a distinct vector inserted with pgsA, pgsB or pgsC, respectively to prepare transgenic plants having one or two nucleic acids selected from pgsA, pgsB and pgsC, and crossing the prepared transgenic plants.

6 . The method of claim 4 wherein the plant is infected with Agrobacterium by a method selected from the group consisting of the leaf disc method, the decompression-humectation method and the direct injection method.

7 . The method of claim 1 wherein the plant is selected from the group consisting of tobacco, Arabidopsis thaliana , rice, soybean and bird's-foot trefoil.

8 . A transgenic plant for producing polyglutamic acid prepared by the method of claim 1 .

9 . The transgenic plant of claim 8 , wherein the plant is in the phase of adult, seed or callus.

10 . The transgenic plant of claim 8 , wherein the plant is tobacco or Arabidopsis thaliana.