A genetically controlled polyacrylic acid induced resistance in Nicotiana species

Several Nicotiana species and cultivars, with and without the N gene, were screened for the effect of polyacrylic acid (PAA) and salicylic acid (SA) on b-protein production and induced resistance. Whilst SA was effective in producing either b-proteins and resistance to a challenge viral infection in all the cultivars tested, the effectiveness of PAA appeared cultivar dependent. Only the cultivars Xanthi-nc (NN), Xanthi (nn) and hybrids between Xanthi-nc (NN) and other N. tabacum cultivars responded to PAA. This is the first time that the genetic determinant for the PAA response has been shown to be sexually transmitted as a dominant character, and also that it is distinct from the N gene.