Patents granted to Japan Tobacco

Specific Patent Information

Patent Number Title, Independent Claims and Summary of Claims Assignee
US 5591616

  • Earliest priority – 7 July 1992
  • Filed – 3 May 1994
  • Granted – 7 Jan 1997
  • Expected expiry – 2 May 2014
Title – Method of transforming monocotyledon

Claim 1A method for transforming a monocotyledon callus, comprising contacting a cultured tissue of a monocotyledon during dedifferentiation wherein said dedifferentiation is obtained by culturing an explant on a dedifferentiation-inducing medium for not less than 7 days or a dedifferentiated cultured tissue of a monocotyledon, with a bacterium belonging to the genus Agrobacterium containing a desired gene.
Claim 17A method for transforming a monocotyledon with a desired gene, comprising:

A) contacting a cultured tissue of said monocotyledon during dedifferentiation thereof, or a dedifferentiated cultured tissue of said monocotyledon, with a suspension of Agrobacterium tumefaciens having a cell population of 106 to 1011 cells/ml for 3-10 minutes, and then
B) culturing said cultured tissue of said monocotyledon during dedifferentiation thereof, or said dedifferentiated cultured tissue of said monocotyledon, on a solid medium for several days together with said Agrobacterium tumefaciens, or
C) adding said Agrobacterium tumefaciens to culture medium in which said cultured tissue of said monocotyledon during dedifferentiation thereof or said dedifferentiated cultured tissue of said monocotyledon is cultured, and continuously culturing said cultured tissue of said monocotyledon during dedifferentiation or said dedifferentiated cultured tissue of said monocotyledon together with said Agrobacterium tumefaciens,

wherein said dedifferentiated cultured tissue of said monocotyledon is selected from the group consisting of a tissue cultured during the process of callus formation which is cultured for not less than 7 days after an explant is placed on a dedifferentiation-inducing medium and a callus, and
wherein said Agrobacterium tumefaciens contains plasmid pTOK162, and said desired gene is present between border sequences of the T region of said plasmid pTOK162, or wherein said desired gene is present in another plasmid contained in said Agrobacterium tumefaciens.

The patent discloses  that “the term ‘dedifferentiated tissue’ …means a callus or an adventitious embryo-like tissue obtained by culturing an explant in a medium containing a plant growth regulator such as an auxin or a cytokinin.”

Japan Tobacco

US 7060876

  • Earliest priority – 7 July 1992
  • Filed – 13 Jan 1999
  • Granted – 13 Jun 2006
  • Expected expiry – 2 May 2014
Title – Method for transforming monocotyledons

Claim 1
A method for transforming a monocot plant comprising:i) culturing an explant of said monocot plant, or a tissue isolated from said explant, for one to six days in a medium comprising at least one auxin to obtain a cultured tissue;
ii) co-culturing the cultured tissue from step i) with an Agrobacterium bacterium comprising a polynucleotide of interest;
iii) selecting cultured tissue into which the polynucleotide of interest has been introduced; and
iv) culturing the selected tissue on a regeneration medium to obtain a transformed monocot plant.
Claim 16
A method for transforming a tissue of a monocot plant comprising:i) culturing an explant of an immature tissue of a monocot plant for one to six days on a medium comprising at least one auxin and that induces dedifferentiation of the cells of the explanted tissue to obtain a dedifferentiating or dedifferentiated cultured immature tissue;
ii) contacting the dedifferentiating or dedifferentiated cultured immature tissue with cells of Agrobacterium bacteria that comprise a vector comprising at least one virulence gene of a Ti plasmid, a left T-DNA border, a right T-DNA border and a polynucleotide of interest located between the left T-DNA border and the right T-DNA border;
thereby obtaining a transformed plant tissue.
Claim 20
A method for obtaining a transformed monocot plant comprisingi) culturing an explant of an immature tissue of a monocot plant for one to six days on a medium comprising at least one auxin and that induces dedifferentiation of the cells of the explanted tissue to obtain a dedifferentiating or dedifferentiated cultured immature tissue;
ii) contacting the dedifferentiating or dedifferentiated cultured immature tissue with cells of Agrobacterium bacteria that comprise a vector comprising at least one virulence gene of a Ti plasmid, a left T-DNA border, a right T-DNA border and a polynucleotide of interest located between the left T-DNA border and the right T-DNA border; thereby obtaining a transformed plant tissue; and
iii) culturing the transformed plant tissue on at least one regeneration medium, thereby obtaining a transformed monocot plant.

Granted US 7060876 is a continuation of US 08/668464 (now abandoned), which is a continuation-in-part of now granted US 5591616.

The claims are generally drawn towards:

  • a method for transforming a monocot plant comprising culturing an explant or a tissue from an explant for one to six days in a medium comprising at least one auxin (claim 1)
  • a method for transforming a tissue of a monocot plant comprising culturing an explant of an immature tissue for one to six days on a medium comprising at least one auxin (claim 16)
  • a method for obtaining a transformed monocot plant comprising culturing an explant of an immature tissue for one to six days on a medium comprising at least one auxin (claim 20)

Granted US 7060876 and US 5591616 together cover the whole duration of the dedifferentiation period of monocot plant tissue that can be used as transformation material by Agrobacterium in the United States.

The term “less than seven days” in the application US 2002/0178463 has been changed to “one to six days”, and there is no limit on the type of plasmid that is contained in the Agrobacterium that is used to transform the monocot plant in granted US 7060876.

US 2002/0178463

  • Earliest priority – 7 July 1992
  • Filed – 13 Jan 1999
  • Pubished – 28 November 2002
  • Granted as US 7060876 (see above)
  • Expected expiry – N/A
Title – Method of transforming monocotyledons

Claim 1A method for transforming a monocotyledon, comprising contacting a cultured tissue of said monocotyledon during dedifferentiation thereof obtained by culturing an explant on a dedifferentiation-inducing medium for less than 7 days with a bacterium belonging to the genus Agrobacterium containing a super binary vector having the virulence region of Ti plasmid pTiBo542 contained in Agrobacterium tumefaciensA281, left and right border sequences of T-DNA of a Ti plasmid or an Ri plasmid of a bacterium belonging to the genus Agrobacterium, and a desired gene located between said left and right border sequences.
Claim 13
A method for transforming a monocotyledon, comprising contacting a cultured tissue of said monocotyledon during dedifferentiation thereof obtained by culturing an explant derived from an immature tissue on a dedifferentiation-inducing medium for less than 7 days with a bacterium belonging to the genus Agrobacterium containing a desired gene and containing a vector having the virulence region of Ti plasmid contained in Agrobacterium tumefaciens.

United States patent application US 2002/0178463 is a continuation-in-part of application US 08/193,058 (now patent US 5,591,616, see above). The content of this application is very similar to the parent application. The main difference in the claims is that independent Claim 1 recites the use of a superbinary vector having the virulence region of a defined Ti plasmid and contained in a specific strain of Agrobacterium tumefaciens and tissue is cultured in dedifferentiating medium for less than 7 days.

In claim 13, the explant is derived from an immature tissue. The application discloses that the “term ‘immature’ means that the tissue has not reached the matured state of the tissue and will mature under conditions which allow the maturation.”  The description doesn’t clarify what physiological or phenotypic properties an immature tissue has but merely basically restates that “immature” means not mature.

AU 667939 B

  • Earliest priority – 7 July 1992
  • Filed – 6 July 1993
  • Granted – 18 April 1996
  • Expected expiry – 5 July 2013
Title – Method of transforming monocotyledon

The lead claim in the Australian patent AU 667939 B is broader than in the United States patent.In the Australian patent, a dedifferentiating or dedifferentiated tissue of a monocot is also used as the initial tissue for transformation, but there is no restriction with respect to a minimum number of days of culture in the medium to induce dedifferentiation.

Claim 1A method for transforming a monocotyledon comprising transforming a cultured tissue during dedifferentiation process or a dedifferentiated cultured tissue of said monocotyledon with a bacteria belonging to genus Agrobacterium containing a desired gene.
EP 604662 A1

  • Earliest priority – 7 July 1992
  • Filed – 6 July 1993
  • Application pending
Title – Method of transforming monocotyledon

The claims submitted in the European application EP 604 662 A1 are the same as the claims of the Australian patent.

Remarks National phase entry of PCT application WO 94/0977 in Canada (CA 2121545) is still pending.

Note: Patent information on this page was last updated on 3 February 2006.