Actinidin levels in fruit of Actinidia species and some Actinidia arguta rootstock-scion combinations
Boyes, S.; Strubi, P.; Marsh, H.
Lebensmittel-Wissenschaft and Technologie 30(4): 379-389
Actinidin, the kiwifruit protease, was measured in the fruit of a number of Actinidia species during their growth, at harvest and during subsequent storage. Actinidia deliciosa cv. Hayward (kiwifruit) fruit actinidin levels were compared to fruit levels measured in cutting-grown plants of species to be used as rootstocks, A. arguta selections and some rootstock-scion combinations. The fruit showed a wide range of actinidin activities, which were influenced by the scion and rootstock genotype. Some trends were seen in rootstock-scion combinations; rootstocks whose fruit had low actinidin levels conferred low levels in the fruit of grafted scion species. Similarly, high levels were seen in scion fruit whose rootstock had high levels. There was a significant scion influence in some combinations. The correlation between actinidin and protein levels suggested control at transcription. An SDS-PAGE gel showed that the density of the actinidin band correlated with the measured actinidin levels. The data suggested that variation in actinidin activity was not due to endogenous inhibitor control or the presence of an inactive zymogen.