T 2435/13 - Crossing of plants

Key points

• This examination appeal is about a method "for producing a B. oleracea plant " comprising a step of "crossing said B. rapa plant with a B. oleracea plant", i.e. crossing between different species. The applicant submits that this method is not excluded from patentability under Article 53(b) EPC because in claim 1 "only partial homologous recombination on limited portions of the respective genomes took place". Therefore, "the claimed method was not directed to a process for the production of plants involving sexually crossing the whole genomes of plants" as specified in G2/07 and G1/08. G2/07 and G1/08 referred to conventional method "based on the sexual crossing of plants (i.e. of their whole genomes)" as being excluded. The present Board has to interpret the "i.e." phrase.
• "The board considers that, in fact, it can rather be inferred from [G2/07 and G1/08] that the EBA considered all methods containing or consisting of steps of sexually crossing the whole genome of plants and the subsequent selection of plants, regardless of those plants being sexually incompatible or not, to be excluded from patentability. In the board's view this is so since it was decisive for the EBA that in such processes, in contrast to other processes to change the genome of plants, such as e.g. irradiation [...], the genetic make-up of the plants resulting from the cross is determined by the result of the meiosis in the parent plants." 

T 2435/13 - link

Claim 1 of the main request read:
"1. A method for producing a B. oleracea plant comprising a monogenic and dominant resistance to clubroot comprising the steps of:
a) obtaining a B. rapa plant resistant to clubroot comprising a monogenic and dominant resistance to clubroot;
b) crossing said B. rapa plant with a B. oleracea plant,
c) rescuing embryos resulting from the cross of step b);
d) regenerating a plant from a embryo of step c);
e) selecting a plant of step d) that is resistant to clubroot comprising a monogenic and dominant resistance to clubroot;
f) back-crossing a plant resulting from step e) with a B. oleracea plant;
g) rescuing embryos resulting from the back-cross of step f); and
h) selecting a plant of step g) that is resistant to clubroot comprising a monogenic and dominant resistance to clubroot."

Reasons for the Decision

1. The appeal is admissible.

Introduction - The invention described in the application

2. Disclosed in the application (see e.g. page 2, lines 6 to 15, page 10, line 5 to page 11, line 2, example 1) is the transfer of a monogenic dominant resistance to clubroot from Chinese cabbage (Brassica rapa) to initially broccoli (B. oleracea) and then further to other B. oleracea cole-crop forms such as white cabbage, cauliflower and Brussels sprouts.

3. The resistance to clubroot was transferred from B. rapa to B. oleracea by means of an interspecific cross (hybridisation) followed by embryo rescue of the hybrid F1 progeny. Clubroot-resistant F1 progeny plants were then used for repeated backcrossing to B. oleracea and disease tests in all backcross generations. Plants resulting from the first backcross (BC1 progeny) were also recovered by embryo rescuing.

4. Embryo rescue - which techniques as such were known in the art - to obtain the F1 (and BC1) progeny after the interspecific cross is necessary in order to overcome the sexual incompatibility between B. rapa and B. oleracea due to the different number of chromosomes (n=10 or 9, respectively) in the two species. Embryo rescue in fact allows the problems of the non-viability of the embryo due to degradation of the endosperm in the seeds comprising the F1 embryos (10 + 9 chromosomes) to be overcome.

5. The method of the invention allows B. oleracea plants with a high level of resistance to clubroot to be produced whereby the resistance is stable and can be transmitted to further generations and transferred to susceptible or less resistant B. oleracea plants.

Main request - claim 1 - essentially biological process for the production of plants (Article 53(b) EPC)

6. Article 53(b) EPC states that "European patents shall not be granted in respect of (b) ... essentially biological processes for the production of plants ...; this provision shall not apply to microbiological processes ...".

7. In the decisions of consolidated cases G 2/07 and G 1/08 (OJ EPO 2012, 130 and 206) the Enlarged Board of Appeal (EBA), after having extensively revised the legislative history of the provision, held that 

 "It must be concluded that the legislator's intention was to exclude from patentability the kind of plant breeding processes which were the conventional methods for the breeding of plant varieties of that time. These conventional methods included in particular those (relevant for the present referrals) based on the sexual crossing of plants (i.e. of their whole genomes) deemed suitable for the purpose pursued and on the subsequent selection of the plants having the desired trait(s). The application of technical means or other forms of human intervention in such processes which helped to perform them was already common. Nevertheless, the said processes were characterised by the fact that the traits of the plants resulting from the crossing were determined by the underlying natural phenomenon of meiosis. This phenomenon determined the genetic make-up of the plants produced, and the breeding result was achieved by the breeder's selection of plants having the desired trait(s). That these were processes to be excluded also follows from the fact that processes changing the genome of plants by technical means such as irradiation are cited as examples of patentable technical processes" (see third paragraph of point "6.4.2.3 Conclusions"; emphasis added by the board).

8. In accordance with this conclusion the EBA formulated answer 1 of the decisions G 2/07 and G 1/08 as follows: "A non-microbiological process for the production of plants which contains or consists of the steps of sexually crossing the whole genomes of plants and of subsequently selecting plants is in principle excluded from patentability as being "essentially biological" within the meaning of Article 53(b) EPC" (emphasis added by the board).

9. The appellant argued in a first line of argument that the claimed method was not a process for the production of plants which the EBA considered to be in principle excluded from patentability as being "essentially biological" within the meaning of Article 53(b) EPC, as it did not involve sexually crossing the whole genomes of plants. By emphasising that conventional breeding processes involved sexual crossing of whole genomes, the EBA construed such processes as being those involving meiotic recombination events throughout the whole genome during the pairing of homologous chromosomes. However, the claimed process did not fall into this category since only partial homologous recombination on limited portions of the respective genomes could take place in the circumstances of the claimed method.

10. The board cannot concur with the appellant's first line of argument. It cannot see any reason to infer from the conclusion of the EBA referred to above (see point 7), or from the further content of the two decisions, that the EBA construed the methods based on "sexually crossing the whole genomes of plants" to be limited to merely those methods involving meiotic recombination events throughout the whole genome during perfect pairing of homologous chromosomes in the process of meiosis.

11. Indeed, the board considers that, in fact, it can rather be inferred from the conclusion quoted in point 7 above that the EBA considered all methods containing or consisting of steps of sexually crossing the whole genome of plants and the subsequent selection of plants, regardless of those plants being sexually incompatible or not, to be excluded from patentability. In the board's view this is so since it was decisive for the EBA that in such processes, in contrast to other processes to change the genome of plants, such as e.g. irradiation (see the end of the quote in point 7), the genetic make-up of the plants resulting from the cross is determined by the result of the meiosis in the parent plants.

12. The board considers that it is in this context that the qualification of the term "sexual crossing of plants" by the wording "(i.e. of their whole genomes)" is to be understood, i.e. the natural phenomena of meiosis determine the genetic make-up of the respective gametes, based on the whole genome of the parent plants, which in turn determines the genetic make-up of the plants resulting from the cross.

13. The board considers that it is in this context also that the term "sexually crossing the whole genomes of plants" in answer 1 of decisions G 2/07 and G 1/08 is to be read and understood.

14. As the claimed method explicitly involves sexually crossing plants (steps (b) and (f)), involving gamete formation by meiosis based on the whole genome of the parent plants, and subsequent selection of plants (steps (e) and (h)), the board judges that it constitutes a process which the EBA considered excluded from patentability as being "essentially biological" within the meaning of Article 53(b) EPC, as formulated in answer 1 of decisions G 2/07 and G 1/08.

15. In a second line of argument the appellant held that, if the board were to decide - as above - that the claimed method constituted a method as defined in answer 1 of decisions G 2/07 and G 1/08, then the claimed method constituted such a process as defined in answer 3 of decisions G 2/07 and G 1/08 and was accordingly not excluded from patentability under Article 53(b) EPC. In fact, the embryo rescue steps were contained within the steps of sexually crossing and selecting of plants defined in the claim and were mandatory prerequisite steps for the clubroot resistance trait to be introduced from Brassica rapa into the genome of the plant produced. Consequently, answer 3 in decision G 2/07 applied to the present case and the claimed subject-matter did not fall within the exceptions of Article 53(b) EPC.

16. In answer 3 of decisions G 2/07 and G 1/08 the EBA held that "[i]f, however, such a process [note: in this case the process defined in answer 1; see point 8 above] contains within the steps of sexually crossing and selecting an additional step of a technical nature, which step by itself introduces a trait into the genome or modifies a trait in the genome of the plant produced, so that the introduction or modification of that trait is not the result of the mixing of the genes of the plants chosen for sexual crossing, then the process is not excluded from patentability under Article 53(b) EPC" (emphasis added by the board).

17. The board concurs with the appellant that the embryo rescue steps in the claimed method, which are as such of a technical nature, are contained within the steps of sexually crossing and selecting. However, the embryo rescue steps by themselves do not introduce the clubroot resistance trait into the genome of the plants produced and the appellant has not argued so. Rather, the introduction of the clubroot trait into the genome of the plants produced is the result of the mixing of the genomes of the plants chosen for the sexual crossing upon the production of the respective gametes by meiosis (see point 12 above).

18. Hence, the claimed method is not a process as referred to in answer 3 of decisions G 2/07 and G 1/08.

19. Accordingly, in view of the above considerations the claimed subject-matter is excluded from patentability for being an essentially biological process within the meaning of Article 53(b) EPC.