title: Comparative EST transcript profiling of peach fruits under different post-harvest conditions reveals candidate genes associated with peach fruit quality.
abstract: BACKGROUND
  Cold storage is used to inhibit peach fruit ripening during shipment to distant markets. However, this cold storage can negatively affect the quality of the fruit when it is ripened, resulting in disorders such as wooliness, browning or leathering. In order to understand the individual and combined biological effects that factors such as cold storage and ripening have on the fruit and fruit quality, we have taken a comparative EST transcript profiling approach to identify genes that are differentially expressed in response to these factors.
  
  
  RESULTS
  We sequenced 50,625 Expressed Sequence Tags (ESTs) from peach mesocarp (Prunus persica O'Henry variety) stored at four different postharvest conditions. A total of 10,830 Unigenes (4,169 contigs and 6,661 singletons) were formed by assembling these ESTs. Additionally, a collection of 614 full-length and 1,109 putative full-length cDNA clones within flanking loxP recombination sites was created. Statistically analyzing the EST population, we have identified genes that are differentially expressed during ripening, in response to cold storage or the combined effects of cold storage and ripening. Pair-wise comparisons revealed 197 contigs with at least one significant difference in transcript abundance between at least two conditions. Gene expression profile analyses revealed that the contigs may be classified into 13 different clusters of gene expression patterns. These clusters include groups of contigs that increase or decrease transcript abundance during ripening, in response to cold or ripening plus cold.
  
  
  CONCLUSIONS
  These analyses have enabled us to statistically identify novel genes and gene clusters that are differentially expressed in response to post-harvest factors such as long-term cold storage, ripening or a combination of these two factors. These differentially expressed genes reveal the complex biological processes that are associated with these factors, as well as a large number of putative gene families that may participate differentially in these processes. In particular, these analyzes suggest that woolly fruits lack the increased boost of metabolic processes necessary for ripening. Additionally, these results suggest that the mitochondria and plastids play a major role in these processes. The EST sequences and full-length cDNA clones developed in this work, combined with the large population of differentially expressed genes may serve as useful tools and markers that will enable the scientific community to better define the molecular processes that affect fruit quality in response to post-harvest conditions and the organelles that participate in these processes.
authors.affiliation: Centro de Biotecnología Vegetal, Universidad Andrés Bello, Santiago, Chile.
authors.forename: Paula
authors.initials: P
authors.lastname: Vizoso
authors.forename: Lee A
authors.initials: LA
authors.lastname: Meisel
authors.forename: Andrés
authors.initials: A
authors.lastname: Tittarelli
authors.forename: Mariano
authors.initials: M
authors.lastname: Latorre
authors.forename: Juan
authors.initials: J
authors.lastname: Saba
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Caroca
authors.forename: Jonathan
authors.initials: J
authors.lastname: Maldonado
authors.forename: Veronica
authors.initials: V
authors.lastname: Cambiazo
authors.forename: Reinaldo
authors.initials: R
authors.lastname: Campos-Vargas
authors.forename: Mauricio
authors.initials: M
authors.lastname: Gonzalez
authors.forename: Ariel
authors.initials: A
authors.lastname: Orellana
authors.forename: Herman
authors.initials: H
authors.lastname: Silva
mesh_terms: D016000:Cluster Analysis; D003080:Cold Temperature; D055028:Comparative Genomic Hybridization; D018744:DNA, Plant / Q000235:genetics; D020224:Expressed Sequence Tags; D005638:Fruit / Q000235:genetics*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D015723:Gene Library; D017343:Genes, Plant; D027861:Prunus / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013892:Thioxanthenes
chemical_list: D018744:DNA, Plant; D013892:Thioxanthenes; C081315:Quantacure QTX