MARTILLAC, France (Reuters) - The owner of one of France's top Bordeaux wine chateaux hopes U.S. President Donald Trump's threat of 200% tariffs on European wine is just posturing because the impact would be devastating if not.

Trump on Thursday threatened to slap a 200% tariff on European wines and other alcoholic products unless the European Union scraps its planned tax on American whiskey.

"We hope this is just a new chapter of 'The Art of the Deal', because if it is not, we could be ruined," said Florence Cathiard, owner of Chateau Smith Haut Laffite, which employs 60 people and cultivates 80 hectares around Martillac, southwest France.

Referring to Trump's 1987 book, she said she hopes the 200% threat is just a negotiating stance to win the upper hand in a standoff with the European Union.

"Look at what he tells people in his book, he says that you have to strike very, very hard, and then you have to negotiate. So we hope it's just a posture," said Cathiard, whose chateau sells more than 20% of its annual production - about 100,000 bottles of red and 18,000 of white - in the United States.

At an average price of about $100 a bottle, a 200% tariff would push the retail price to $300.

"It will be impossible to sell it if you have to multiply by three," she said, adding that the U.S. threat is another blow after losing Chinese markets and stiff competition from low-wage Latin American producers.

"We have already lost China, three years ago, when China closed itself. So we sent brand ambassadors to Southeast Asia to compensate, and we managed, at high cost. But what can replace the U.S.? Not Russia, you know? We are a little lost," she said.

Cathiard said the French wine industry is pinning its hopes on French luxury goods billionaire Bernard Arnault, Europe's richest man, who attended Trump's inauguration alongside American tech tycoons.

"He knows Donald Trump well. Maybe he will build a factory, or something for bags or fashion in the States. And maybe he will manage for us, because he also has interests in cognac and wine, to escape this awful tax," she said.

EU wine exports to the United States were worth 4.9 billion euros last year, accounting for 29% of the EU's overall exports of wine, according to EU statistics agency Eurostat. Of all EU wine exports to the United States, France made up almost half and Italy almost 40%.

"If Trump makes good on his threat, that will be the end of us. We hope it is just posturing," Cathiard said.