Trump has uncorked tariffs on China, and now many U.S. companies may be feeling the heat. 

Retaliation from China might not target the same sectors the U.S.-sanctioned tariffs do. U.S. trade representative Robert Lighthizer, who said he is still "gaming out what would happen" should the Chinese retaliate, noted in the Wednesday House Ways and Means Committee meeting that U.S. agriculture will almost inevitably be a target.

Lighthizer's admission came the same day as an editorial in China's Global Times stated the following: "The Trump administration has repeatedly accused China of violating international trade rules and threatened to impose higher tariffs on Chinese products. But the U.S. is actually the breaker of WTO rules, which can be seen clearly by how subsidized U.S. soybeans are dumped on China."

The tariffs are the latest in a series of protectionist trade policy moves from the Trump White House. But who could these tariffs hurt most?

China is the world's largest soybean purchaser, while the U.S. has recently become its biggest producer. A trade war with China might mean U.S. agriculture takes the brunt of this hit.

Companies such as food processor Archer-Daniels-Midland Co. (ADM) , agribusiness food producer Bunge Ltd. (BG) and agrochemical firm Monsanto Co. (MON) might lose business in high-demand China markets.

Multinational chemical company and Action Alerts Plus holding DowDuPont Inc. (DWDP) , crop nutrient miner Mosaic Co. (MOS) and fertilizer distributor CF Industries Holdings Inc. (CF) could as well.

There's also Boeing Co. (BA) , which is the single-largest U.S. exporter and counts China as a crucial market. A trade war with the country could mean China would turn to other manufacturers, such as Airbus (EADSY) .

The same could be said for other big-industry companies that manufacture durables used in agriculture, including Deere & Co. (DE) , AGCO Corp. (AGCO) , CNH Industrial NV (CNHI) , Lindsay Corp. (LNN) , Titan International Inc. (TWI) and Toro Co. (TTC) .

The market has already taken notice of the possibility of a trade war undermining U.S.-China business, too. The iShares China Large-Cap ETF (FXI) fell more than 2.4% in premarket trading on Thursday, while the Xtrackers Harvest CSI 300 China fund (ASHR) dipped about 1%.