Beauty of Arctic® apples is more than skin deep

nonbrowning apple scienceTruly nonbrowning Arctic® apples are a brilliantly engineered solution to a real-world problem. Apple browning is much more than a cosmetic issue – it has real economic costs for each link of the supply chain from tree to table.

So how’d we solve that problem, exactly? By marrying the age-old art of apple breeding with modern science tools.

Hot Potato

Our nonbrowning solution finds its roots in research originally done to address browning in potatoes. Potatoes suffer enzymatic browning damage as much if not more than apples, also resulting in significant product loss due to cullage and shrink. Polyphenol oxidase (PPO) is at the heart of enzymatic browning of both potatoes and apples. Australian researchers pioneered a genetic modification to silence potatoes’ PPO genes.  We licensed that gene silencing technology, then perfected and expanded on it in apples.

Apple-to-apple transformation

apple inspecting under magnifying glassOur science team silenced apples’ PPO genes using genes isolated from apples. Arctic apples produce less than 10 percent of the PPO of their conventional counterparts – not enough to allow apples to brown.

To create nonbrowning Arctic varieties, our low PPO-producing gene sequence – dubbed GEN-03 – is inserted into the parent cultivar’s DNA. A promoter and terminator gene sequence start and end that transformation process. It is a very targeted and specific gene modification that silences the PPO enzyme but does not change any other aspect of the cultivar.

With a little help from our friends

Apples’ own genetic promoters and terminators are too weak to trigger this transformation, so the Arctic apple transformation uses proven biotechnology aids. A promoter derived from cauliflower mosaic virus initiates the Arctic apple transformation, while nopaline synthase terminates it; Agrobacterium tumefaciens aids the process.

The proof is in the PCR

The marker nptII gene, explained in more detail here, and polymerase chain reaction (PCR) testing confirms the transformation executed properly. The Arctic apple plantlets are grown in the lab until they can be micrografted to apple rootstock to prepare them for planting. Total time from transformation to a young tree with fruit is approximately 24 months.

brown vs nonbrowning appleYour favorite apple varieties, now nonbrowning

Arctic apples aren’t slow browning, they aren’t low browning – they are truly nonbrowning.  An Arctic apple will decay naturally just like any other apple, but it will not turn brown from bruising, cutting or biting – not in minutes, hours or days.

Any apple variety can be engineered to be a nonbrowning Arctic apple. We decided to first convert two of the most popular apple varieties of all time, Golden Delicious and Granny Smith. Next in the queue are Fuji and Gala.

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