* Cell wall reinforcement (cellulose, lignin, suberin, callose, cell wall proteins)
* Antimicrobial chemicals, including reactive oxygen species such as hydrogen peroxide or peroxynitrite, or more complex phytoalexins such as genistein or camalexin
* Antimicrobial proteins such as defensins, thionins, or PR-1
* Antimicrobial enzymes such as chitinases, beta-glucanases, or peroxidases
* Hypersensitive response – a rapid host cell death response associated with defence induction.