title: ACC oxidase (ACO) genes in Trifolium occidentale (L.) and their relationship to ACO genes in white clover (T. repens L.) and T. pallescens (L.).
abstract: The identification and expression of two ACC oxidase (ACO) genes during leaf development in Trifolium occidentale (L.), one of the putative ancestral genomes of the allotetraploid, T. repens (L.; white clover), is described. In common with observations made in T. repens, the ACO genes displayed differential expression, with a TR-ACO2-like gene (designated TO-ACO2) confined to developing and early mature-green leaf tissue while expression of a TR-ACO3-like gene (designated TO-ACO3) is highest in leaves at the onset and during senescence. Biochemical analysis of TO-ACO2 revealed that both accumulation of the protein (determined by western analysis with a TR-ACO2 antibody) and enzyme activity matched the transcriptional activity of TO-ACO2. Western analysis also revealed that the Tr-ACO2 antibody recognised a protein of 37 kDa as a putative TP-ACO2 in T. pallescens. The 3'-UTRs of TO-ACO2 and TO-ACO3 were then compared with the 3'-UTRs of a TR-ACO2-like and TR-ACO3-like gene from T. pallescens, the other proposed ancestral genome (or closely related to the ancestor) of T. repens, with identity values of 87.8% for the ACO2-like genes and 94.8% for the ACO3-like genes. Comparison of the 3'-UTRs of TO-ACO2 with a TO-ACO2-like gene in T. repens (designated TR(O)-ACO2) and TP-ACO2 with a TP-ACO2-like gene in T. repens (designated TR(P)-ACO2) revealed identities of 100% and 96.6%, respectively, lending good support to T. occidentale as one of the ancestral genomes of T. repens. A similar comparison of the 3'-UTRs of TO-ACO3 with a TO-ACO3-like gene in T. repens (designated TR(O)-ACO3) and TP-ACO3 with a TP-ACO3-like gene in T. repens (designated TR(P)-ACO3) revealed identities of 99.5% and 97.9%, respectively, again supporting T. occidentale as one of the ancestral genomes. Further, these data confirm that both TO-ACO-like and TP-ACO-like genes are expressed in the allotetraploid T. repens.
authors.affiliation: Institute of Molecular Biosciences, Massey University, Palmerston North, New Zealand.
authors.forename: Zhenning
authors.initials: Z
authors.lastname: Du
authors.forename: Susanna
authors.initials: S
authors.lastname: Leung
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Dorling
authors.forename: Michael T
authors.initials: MT
authors.lastname: McManus
mesh_terms: D000594:Amino Acid Oxidoreductases / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D005075:Biological Evolution; D016922:Cellular Senescence; D015870:Gene Expression; D017343:Genes, Plant; D018745:Genome, Plant; D008969:Molecular Sequence Data; D010802:Phylogeny; D018515:Plant Leaves / Q000254:growth & development*; D011123:Polyploidy; D017385:Sequence Homology; D013045:Species Specificity; D029921:Trifolium / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development
chemical_list: D000594:Amino Acid Oxidoreductases; C059460:1-aminocyclopropane-1-carboxylic acid oxidase