Fuente: WIPO "tobacco agriculture" The invention discloses an application of a PR-1B protein in tobacco plant breeding, which comprises the following steps: detecting the expression quantity of the PR-1B protein in a tobacco plant infected with black shank, and when the expression quantity of the PR-1B protein is in an overexpression state, the tobacco plant has the characteristic of resisting black shank, and when the expression quantity of the PR-1B protein is in an overexpression state, the tobacco plant has the characteristic of resisting black shank; the amino acid sequence of the PR-1B protein is as shown in SEQ ID No: 1. The PR-1B protein disclosed by the invention can be used for reliably and sensitively detecting the resistance of tobacco to black shank, provides a brand new way for screening tobacco black shank resistant varieties and assisting traditional cross breeding, and is suitable for large-scale popularization and application.