Tobacco squalene epoxidase protein, tobacco squalene epoxidase gene and applications of tobacco squalene epoxidase gene

The invention discloses a tobacco squalene epoxidase protein with an amino acid sequence shown in SEQIDNO:1. A tobacco squalene epoxidase gene NtSE is a key control gene in the synthetic route of sterol in tobaccos. The gene is specifically highly expressed in young tissues, a built virus mediated gene silenced carrier TRV-NtSE is inoculated to a Ben's tobacco, and then a plant with a high silencing efficiency is obtained; through detecting the content of phytosterol in the Ben's tobacco, a situation that the sterol content of the gene silenced plant is significantly reduced by 21.37% is found, which shows that the silencing of the gene can significantly reduce the sterol content of the plant. The tobacco squalene epoxidase gene NtSE is a key control gene in the synthetic route of sterol in tobaccos, can be used for regulating the sterol content of tobaccos, and facilitates the genetic engineering breeding of low-sterol high-quality tobaccos.