title: Developmentally related responses of maize catalase genes to salicylic acid.
abstract: The response of the maize catalase genes (Cat1, Cat2, and Cat3) to salicylic acid (SA) was examined at two distinct developmental stages: embryogenesis and germination. A unique, germination-related differential response of each maize catalase gene to various doses of SA was observed. During late embryogenesis, total catalase activity in scutella increased dramatically with 1 mM SA treatment. The accumulation of Cat2 transcript and CAT-2 isozyme protein provided the major contribution to the observed increase in total catalase activity. This increase was paralleled by the enhanced growth of germinated embryos at that stage. In a CAT-2 null mutant line, a full compensation of total catalase activity by the CAT-1 isozyme was observed in the presence of SA. This suggests that catalase is important for maintenance of normal cellular processes under stress conditions. SA at 1 mM, which enhances growth of precociously germinated embryos, appeared to inhibit seed germination at 1 day after inhibition. Furthermore, Cat2 transcript accumulation was inhibited at this stage. SA is probably not a direct signal for the induction of the catalase genes. Other signals, possibly germination-related regulator(s), might be responsible for the induction of the catalase genes. The effect of SA on the activity of purified catalase protein was also examined.
authors.affiliation: Department of Genetics, North Carolina State University, Raleigh 27695, USA.
authors.forename: L
authors.initials: L
authors.lastname: Guan
authors.forename: J G
authors.initials: JG
authors.lastname: Scandalios
mesh_terms: D002374:Catalase / Q000096:biosynthesis* / Q000235:genetics* / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D017343:Genes, Plant / Q000187:drug effects; D007527:Isoenzymes / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D018749:RNA, Plant / Q000302:isolation & purification / Q000378:metabolism; D012459:Salicylates / Q000494:pharmacology*; D020156:Salicylic Acid; D012639:Seeds; D014158:Transcription, Genetic; D003313:Zea mays / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*
chemical_list: D007527:Isoenzymes; D018749:RNA, Plant; D012459:Salicylates; D002374:Catalase; D020156:Salicylic Acid