title: Identification and characterization of MOR-CP, a cysteine protease induced by ozone and developmental senescence in maize (Zea mays L.) leaves.
abstract: Among the different classes of endoproteases, cysteine proteases are consistently associated with senescence, defense signaling pathways and cellular responses to abiotic stresses. The objectives of this work were to study the effects of various concentrations of ozone on gene expression and enzymatic activity for papain-like cysteine proteases (PLCPs), in the leaves of maize plants grown under field conditions. Leaves from ranks 12 and 10 (cob leaf) were harvested regularly over a long-term artificial ozone fumigation experiment (50 d). Tissues were tested for transcriptional and activity changes concerning cysteine proteases, using qRT-PCR for the newly identified ozone-responsive PLCP gene (Mor-CP) and synthetic oligopeptide Boc-Val-Leu-Lys-AMC as a PLCP-specific substrate, respectively. Results showed that developmental senescence induced a significant and progressive rise in CP activity, only in the older leaves 10 and had no effect on Mor-CP gene expression levels. On the other hand, ozone dramatically enhanced Mor-CP mRNA levels and global PLCP enzymatic activity in leaves 12 and 10, particularly toward the end of the treatment. Ozone impact was more pronounced in the older leaves 10. Together, these observations concurred to conclude that ozone stress enhances natural senescence processes, such as those related to proteolysis.
authors.affiliation: Equipe IPE, iEES Paris UMR 7618, Université Paris Est-Créteil, 61 avenue du Général de Gaulle, 94010 Créteil cedex, France.
authors.forename: Rafiq
authors.initials: R
authors.lastname: Ahmad
authors.affiliation: Equipe IPE, iEES Paris UMR 7618, Université Paris Est-Créteil, 61 avenue du Général de Gaulle, 94010 Créteil cedex, France.
authors.forename: Yasmine
authors.initials: Y
authors.lastname: Zuily-Fodil
authors.affiliation: Equipe IPE, iEES Paris UMR 7618, Université Paris Est-Créteil, 61 avenue du Général de Gaulle, 94010 Créteil cedex, France.
authors.forename: Chantal
authors.initials: C
authors.lastname: Passaquet
authors.affiliation: UMR 1091 Environnement et Grandes Cultures, INRA, 78850 Thiverval-Grignon, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Bethenod
authors.affiliation: UMR 1091 Environnement et Grandes Cultures, INRA, 78850 Thiverval-Grignon, France.
authors.forename: Romain
authors.initials: R
authors.lastname: Roche
authors.affiliation: Equipe IPE, iEES Paris UMR 7618, Université Paris Est-Créteil, 61 avenue du Général de Gaulle, 94010 Créteil cedex, France. Electronic address: repellin@u-pec.fr.
authors.forename: Anne
authors.initials: A
authors.lastname: Repellin
mesh_terms: D057056:Cysteine Proteases / Q000235:genetics* / Q000378:metabolism*; D010126:Ozone / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000201:enzymology / Q000254:growth & development; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors; D015854:Up-Regulation / Q000187:drug effects*; D003313:Zea mays / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development
chemical_list: D010940:Plant Proteins; D012333:RNA, Messenger; D010126:Ozone; D057056:Cysteine Proteases
keywords: Global papain-like cysteine protease activities; Papain-like cysteine proteases; RT-qPCR; Tropospheric O(3); Zea mays L.