CHIT1 and infection: The plant defence reaction in response to infection with the wild type and non-virulent Δgnt2 strains was analysed by the quantification of transcript levels of defence-related genes encoding basic glucanase (gluB) [65], acidic chitinase 3 (chi3), basic chitinase 9 (chi9) [66] and pathogenesis-related protein 1 (pr-1) [65] in tomato plant roots at three days post-inoculation, using quantitative real-time RT-PCR (Figure 4B).