title: Differential expression within the LOX gene family in ripening kiwifruit.
abstract: Real-time quantitative PCR was used to study lipoxygenase (LOX) gene expression patterns in kiwifruit (Actinidia deliciosa [A. Chev.] C.F. Liang et A.R. Ferguson var. deliciosa cv. Hayward) during fruit ripening, and in response to ethylene and low temperature during post-harvest storage. Six LOX genes were identified and cloned from a kiwifruit EST database. All were expressed in vegetative tissues and in the fruit. Expression of AdLox1 and AdLox5 increased markedly as fruit developed to the climacteric stage and were up-regulated by ethylene treatment, following a similar pattern to LOX enzyme activity. By contrast, AdLox2, AdLox3, and AdLox4 transcripts were negatively associated with ethylene accumulation, and ethylene application enhanced the decline in transcript levels. Transcripts of AdLox6 declined with fruit ripening. The fruit showed no ripening changes at low temperature, where transcripts of AdLox1 and AdLox6 were slightly induced about 72 h after harvest, suggesting an adaptive response to low temperature. Transient expression of the ethylene-responsive AdLox1 gene in tobacco leaves led to significant degradation of chlorophyll and promoted tissue senescence, whereas AdLox2 had no such effect. The results showed that the six LOX genes were differentially regulated during kiwifruit ripening and senescence, forming two groups, one active in ripening and responsive to ethylene and the other more constitutively expressed. The possible roles of individual LOX isoforms in kiwifruit are discussed.
authors.affiliation: Laboratory of Fruit Molecular Physiology and Biotechnology/The State Agriculture Ministry Laboratory of Horticultural Plant Growth, Development and Biotechnology, Zhejiang University, Huajiachi Campus, Hangzhou 310029, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.forename: Kunsong
authors.initials: K
authors.lastname: Chen
authors.forename: Judith
authors.initials: J
authors.lastname: Bowen
authors.forename: Andrew
authors.initials: A
authors.lastname: Allan
authors.forename: Richard
authors.initials: R
authors.lastname: Espley
authors.forename: Sakuntala
authors.initials: S
authors.lastname: Karunairetnam
authors.forename: Ian
authors.initials: I
authors.lastname: Ferguson
mesh_terms: D029042:Actinidia / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development*; D000595:Amino Acid Sequence; D003080:Cold Temperature; D005030:Ethylenes / Q000494:pharmacology; D020224:Expressed Sequence Tags; D005638:Fruit / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D008084:Lipoxygenase / Q000235:genetics / Q000378:metabolism*; D008315:Malondialdehyde / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D010937:Plant Growth Regulators / Q000494:pharmacology; D018515:Plant Leaves / Q000235:genetics / Q000378:metabolism; D030821:Plants, Genetically Modified / Q000254:growth & development / Q000378:metabolism; D016133:Polymerase Chain Reaction; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D014026:Nicotiana / Q000235:genetics
chemical_list: D005030:Ethylenes; D010937:Plant Growth Regulators; D020033:Protein Isoforms; D008315:Malondialdehyde; C036216:ethylene; D008084:Lipoxygenase