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Relationship of Endopolygalacturonase Inhibitor Activity to the Rate of Fungal Rot Development in Apple Fruits
Author(s) -
Brown Averil E.
Publication year - 1984
Publication title -
journal of phytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 60
eISSN - 1439-0434
pISSN - 0931-1785
DOI - 10.1111/j.1439-0434.1984.tb00485.x
Subject(s) - biology , penicillium expansum , orange (colour) , glomerella cingulata , inoculation , fungi imperfecti , horticulture , mangifera , botany , cultivar , rutaceae , postharvest , colletotrichum gloeosporioides
An inhibitor extracted form the cell walls of apple fruits suppressed the activity of endopopygalacruronases (endo‐PGs) produced in vivo and in vitro by Nectria galligena, Phomopsis mali, Fusarium Lateritium and Glomerella cingulata but not the endo‐PGs produced by Penicillium expansum or Phytophtobora syringae. Of four apple cultivars tested Granny Smith tissue contained the highest levels of inhibitor and Cox's Orange Pippin contained the least. Linear rot expansion in the four apple cultivars inoculated with N. galligena was inversely related to inhibitor activity in the fruit tissue, rot development being slowest in Granny Smith fruits and most rapid in Cox's Orange Pippin fruits. Rot expansion in fruits inoculated with P. expansum bore no such relationship to inhibitor activity in the tissue Apple tissue maceration by the endo‐PGs from N. galligena, P. mali. F. lateritium and G. cingulata was similarly related to inhibitory activity in the fruit. The properties of the partially purified inhibitor were consistent with it being proteinaceous but the relative slowness with which it was hear inactivated and the presence of a small percentage of carbohydrate might indicate that it was a glycoprotein.