Authors: Tao Fan Natalia V Bykova Christof Rampitsch Tim Xing
Publish Date: 2016/03/17
Volume: 146, Issue: 2, Pages: 293-304
Abstract
A putative serine protease with a potential role in the plant biotic and abiotic stress response was purified from wheat leaf apoplastic fluid and partially characterized Following twodimensional electrophoresis a protein of Mr = 75 k and a pI of 42 to 45 was observed This protein displayed ingel protease activity and was specifically inhibited by phenylmethanesulfonyl fluoride and partially inhibited by Ca2+ and Zn2+ but not by E64 or leupeptin An internal tryptic fragment of 13 amino acids was identified by MALDI QqTOF MS/MS and this peptide showed a high level of homology 85–100 identity to a highly conserved region of known plant subtilisinlike proteases We demonstrated that the protease activity increased until a late stage of wheat leaf development and increased in response to heat shock In both cases Rubisco large subunit was degraded with time Protease activity was also increased during biotic stress Leaves challenged with leaf rust Puccinia triticina showed an approximately three fold increase in protease activity during an incompatible interaction compared to activity in mockinoculated leaves and to leaves in a compatible leaf rust interaction These results suggest that the expression of this serine protease could be involved in the defense response against both abiotic and biotic stresses
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