title: Identification and characterization of cDNAs encoding ethylene biosynthetic enzymes from Pelargonium x hortorum cv Snow Mass leaves.
abstract: Two Pelargonium 1-aminocyclopropane-1-carboxylate (ACC) synthase cDNAs (GAC-1 and GAC-2) were identified and characterized. GAC-1 is 1934 bp long with a 1446-bp open reading frame encoding a 54.1-kD polypeptide. GAC-2 is a 1170-bp-long ACC synthase polymerase chain reaction fragment encoding 390 amino acids. Expression of GAC-1 and GAC-2 together with a previously identified ACC oxidase (GEFE-1) was examined in different Pelargonium plant parts, and leaves were subjected to osmotic stress (sorbitol), metal ion stress (CuCl2), auxin (2,4-dichlorophenoxyacetic acid [2,4-D]), and ethylene. GAC-1 expression was not detectable in any of the plant parts tested, whereas high levels of GAC-2 were expressed in the leaf bud, young leaf, young floret, fully open floret, and senescing floret. GAC-2 was expressed to a lesser degree in fully expanded leaves or roots and was undetectable in old leaves and floret buds. GEFE-1 was detectable at all leaf ages tested, in young and fully open florets, and in the roots; however, the highest degree of expression was in the senescing florets. GAC-1 was induced by sorbitol. Both GAC-1 and GAC-2 were only slightly affected by CuCl2 and induced indirectly by 2,4-D. GEFE-1 was highly induced by sorbitol, CuCl2, and 2,4-D. GAC-1, GAC-2, and GEFE-1 were unaffected by ethylene treatment. These results suggest that GAC-1 is only induced by stress and that GAC-2 may be developmentally regulated, whereas GEFE-1 is influenced by both stress and development.
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015139:Blotting, Southern; D003300:Copper / Q000494:pharmacology; D018076:DNA, Complementary / Q000737:chemistry* / Q000302:isolation & purification; D005030:Ethylenes / Q000378:metabolism / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000502:physiology; D007210:Indoleacetic Acids / Q000494:pharmacology; D007527:Isoenzymes / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification; D008190:Lyases / Q000096:biosynthesis* / Q000737:chemistry / Q000302:isolation & purification; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D063245:Plant Development; D018515:Plant Leaves; D010944:Plants / Q000201:enzymology* / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification; D013012:Sorbitol / Q000494:pharmacology
chemical_list: D018076:DNA, Complementary; D005030:Ethylenes; D007210:Indoleacetic Acids; D007527:Isoenzymes; D011994:Recombinant Proteins; D013012:Sorbitol; D003300:Copper; C036216:ethylene; D008190:Lyases; C021773:1-aminocyclopropanecarboxylate synthase; C029892:cupric chloride