Obviousness

The obviousness of US patent 10947555 under 35 U.S.C. § 103 can be established by combining several prior art references, particularly those identified in the Inter Partes Review (IPR) proceedings. A person having ordinary skill in the art (POSA) at the priority date of April 30, 2004, would have been motivated to combine these references to achieve the claimed invention.

The core inventive concept of US10947555 revolves around the AAD-1 gene and the resulting AAD-1 protein (with at least 95% amino acid identity to SEQ ID NO:11), which confers resistance to both phenoxy auxin herbicides (like 2,4-D) and aryloxyphenoxypropionate (AOPP) herbicides in plants. The patent also describes plant-optimized versions of this gene and the stacking of this trait with other herbicide resistances like glyphosate tolerance.

Here's an analysis of relevant prior art combinations and the motivation for a POSA to combine them:

1. Combination for the AAD-1 Enzyme and its Dual Specificity:

• References: Westendorf et al. (2002) and Westendorf et al. (2003).
• Disclosure:
  • Westendorf et al. (2002) explicitly describes the isolation and characterization of a novel 2,4-D/α-ketoglutarate dioxygenase, named rdpA, from Sphingobium herbicidovorans. This enzyme was noted as being distinct from previously known tfdA proteins, having only 28% amino acid identity to tfdA from Ralstonia eutropha [cite: Westendorf et al., 2002]. The US10947555 patent itself states that AAD-1 (v1) is derived from Sphingobium herbicidovorans and is related to rdpA [cite: Westendorf et al., 2002].
  • Westendorf et al. (2003) further characterizes the rdpA enzyme, demonstrating its ability to catalyze the first step in the mineralization of both (R)-dichlorprop (a phenoxypropionic acid) and 2,4-D (a phenoxyacetic acid) [cite: Westendorf et al., 2003]. This publication, therefore, explicitly discloses the dual-specificity of the rdpA (AAD-1) enzyme for both phenoxyacetic and phenoxypropionic acid structures.
• Motivation for a POSA: A POSA would have recognized the importance of an enzyme capable of degrading two different classes of aryloxyalkanoate herbicides, as disclosed by Westendorf et al. (2003). The patent itself notes that "Aryloxyalkanoate chemical substructures are a common entity of many commercialized herbicides including the phenoxy auxins (such as 2,4-D and dichlorprop), pyridyloxy auxins (such as fluroxypyr and triclopyr), aryloxyphenoxypropionates (AOPP) acetyl-coenzyme A carboxylase (ACCase) inhibitors (such as haloxyfop, quizalofop, and diclofop)" [cite: AAD-1, Aryloxyalkanoate chemical substructures]. Given the disclosed activity of rdpA against phenoxypropionic acids, a POSA would have a reasonable expectation of success that this enzyme could also act on other aryloxyalkanoate structures, specifically aryloxyphenoxypropionates (AOPP herbicides), due to their shared structural features. The continued need for novel herbicide resistance mechanisms would motivate a POSA to explore such an enzyme.

2. Combination for Transgenic Plants with Herbicide Resistance:

• References: Lyon '147, Streber et al. (1989), Lyon et al. (1989), Lyon et al. (1993), and Castle (2005) in combination with Westendorf et al. (2002, 2003).
• Disclosure:
  • Lyon '147, Streber et al. (1989), Lyon et al. (1989), and Lyon et al. (1993) collectively teach the established art of generating 2,4-D resistant transgenic plants by introducing bacterial tfdA-type genes. These references demonstrate the feasibility and methods for genetically engineering plants to express bacterial enzymes for herbicide detoxification [cite: TfdA, TfdA].
  • Castle (2005) further describes methods and compositions for conferring herbicide resistance to plants, focusing on synthetic auxin herbicides such as 2,4-D, demonstrating ongoing work and interest in this area [cite: Castle].
• Motivation for a POSA: With the identification of the rdpA (AAD-1) gene and its dual activity by Westendorf et al. (2002, 2003), a POSA would be strongly motivated to apply the well-known techniques for creating herbicide-resistant plants (as taught by Lyon '147, Streber et al., Lyon et al. (1989, 1993), and Castle (2005)) to this new enzyme. The goal would be to confer broad-spectrum resistance to both phenoxy auxin and AOPP herbicides in crops, which would address the increasing problem of weed resistance and the need for more robust weed control options. The expectation of success would be high given the established precedent of using bacterial dioxygenases for herbicide detoxification in transgenic plants.

3. Plant-Optimized Gene Expression:

• References: General knowledge in molecular biology, as acknowledged in US10947555, combined with the above.
• Disclosure: The patent itself discusses that "heterologous genes are more efficiently expressed in (the cytoplasm of) plant cells" and that re-designing a heterologous gene "for optimal expression, using codon bias more closely aligned with the target plant sequence, whether a dicot or monocot species" was an "additional step in the design of genes encoding a bacterial protein" [cite: Maize].
• Motivation for a POSA: Optimizing gene sequences for expression in a target host, such as adjusting codon bias for plant expression, was a routine molecular biology technique known to a POSA at the time of the invention. Given the goal of achieving effective herbicide resistance in transgenic plants, a POSA would naturally be motivated to optimize the rdpA (AAD-1) gene sequence for robust expression in plant systems to maximize the detoxification effect.

4. Stacking with Other Herbicide Resistance Traits:

• References: Monson (2000) combined with the above.
• Disclosure: Monson (2000) teaches methods and compositions for conferring glyphosate tolerance to plants [cite: Monson]. The US10947555 patent itself describes stacking AAD-1 with other herbicide resistance genes, including glyphosate resistance, to provide "broader and more robust weed control and herbicide resistance management options" [cite: the subject invention].
• Motivation for a POSA: The widespread adoption of glyphosate-tolerant crops and the emergence of glyphosate-resistant weeds created a clear motivation for a POSA to develop multi-herbicide tolerant crops. Combining the dual 2,4-D/AOPP resistance of AAD-1 with existing glyphosate tolerance (as taught by Monson) would be an obvious strategy to provide a comprehensive weed control solution, delaying the development of further herbicide resistance and offering greater flexibility to growers.

Conclusion:

A POSA, motivated by the ongoing challenges of weed control and the established success of genetic engineering for herbicide resistance, would have combined the teachings of:

1. Westendorf et al. (2002) and (2003) to identify the rdpA (AAD-1) enzyme and recognize its dual activity against phenoxyacetic and phenoxypropionic acid structures (thereby suggesting activity against AOPP herbicides due to structural similarities).
2. Lyon '147, Streber et al. (1989), Lyon et al. (1989), Lyon et al. (1993), and Castle (2005) to apply established methods of transforming plants with bacterial genes to confer herbicide resistance.
3. General knowledge of molecular biology to optimize the rdpA gene for plant expression (e.g., codon optimization).
4. Monson (2000) to incorporate the newly conferred dual resistance with existing glyphosate resistance, thereby creating a plant with resistance to multiple herbicide classes.

The IPR2024-00179 Final Written Decision, which found claims 1, 10, 16, 17, 21, 22, 25, 26, 27, 28, and 30 unpatentable under 35 U.S.C. § 103(a) over combinations of these very references, further validates this obviousness analysis. [cite: PTAB case IPR2024-00179 filed (Final Written Decision)]