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Delay of Iris flower senescence by protease inhibitors
Author(s) -
Pak Caroline,
Van Doorn Wouter G.
Publication year - 2005
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2004.01226.x
Subject(s) - senescence , protease , biology , iris (biosensor) , botany , enzyme , microbiology and biotechnology , biochemistry , computer science , artificial intelligence , biometrics
Summary• Visible senescence of the flag tepals in Iris x hollandica (cv. Blue Magic) was preceded by a large increase in endoprotease activity. Just before visible senescence about half of total endoprotease activity was apparently due to cysteine proteases, somewhat less than half to serine proteases, with a minor role of metalloproteases. • Treatment of isolated tepals with the purported serine protease inhibitors AEBSF [4‐(2‐aminoethyl)‐benzenesulfonyl fluoride] or DFP (diisopropyl‐fluorophosphate) prevented the increase in endoprotease activity and considerably delayed or prevented the normal senescence symptoms. • The specific cysteine protease‐specific E‐64d reduced maximum endoprotease activity by 30%, but had no effect on the time to visible senescence. Zinc chloride and aprotinin reduced maximum endoprotease activity by c . 50 and 40%, respectively, and slightly delayed visible senescence. A proteasome inhibitor (Z‐leu‐leu‐Nva‐H) slightly delayed tepal senescence, which indicates that protein degradation in the proteasome may play a role in induction of the visible senescence symptoms. • It is concluded that visible senescence is preceded by large‐scale protein degradation, which is apparently mainly due to cysteine‐ and serine protease activity, and that two (unspecific) inhibitors of serine proteases considerably delay the senescence symptoms.