Housekeeping genes such as GAPDH,β-actin and 18s were used as the reference genes (refer to Table 16 for the sequences) for the normalization ofquantitative expression analysis in S. tetraptera (Song et al., 2008). Although
this is a different species than the AUT kowhai, the Sophora species in New Zealand are closely related, so it is likely that the housekeeping gene sequences may be the same. Therefore primers for the β-actin housekeeping 68 gene used by Song et al.,(2008) in S. tetraptera were tested on the AUT kowhai (S.microphylla x S.chathamica hybrid) in the present
study to see if they would amplify the correctly sized PCR product.