Plant & Animal Genomes XIV Conference

January 14-18, 2006
Town & Country Convention Center
San Diego, CA

Genomic Resources For Citrus Research

Javier Forment¹ , Jose Gadea¹ , Luis Navarro² , Vicente Pallas¹ , Miguel A. Perez-Amador¹ , Ramon Serrano¹ , Manuel Talon² , Lorenzo Zacarias³ , Vicente Conejero¹

¹  Instituto de Biologia Molecular y Celular de Plantas (IBMCP), UPV-CSIC, Av. Naranjos s/n 46022 Valencia, Spain

²  Instituto Valenciano de Investigaciones Agrarias (IVIA), Carretera Moncada-Náquera, Km 4,5. 46113 Moncada(Valencia), Spain

³  Instituto de Agroquímica y Tecnología de Alimentos (IATA), Apto 73, 46100 Burjasot(valencia),Spain

In order to create a resource for the citrus research community, we, at the Citrus Functional Genomics Project (CFGP), have developed different genomic tools for large-scale studies of biological processes relevant to citriculture. Due to its economical importance, Clementine mandarine (Citrus clementina) has been selected for generation of these tools. This includes a previously reported genome-wide EST collection and cDNA microarray (Forment et al., 2005. Plant Mol. Biol., 57: 375-391), which is being used to characterize the citrus transcriptome in different biological conditions of interest.
The EST collection has been extended to include 86,074 high-quality sequences generated from 52 different cDNA libraries covering different tissues, developmental stages and stress conditions. EST clustering showed that these sequences correspond to around 25,000 putative unigenes, which represent an almost complete fraction of the expected total number of genes in the citrus genome. Furthermore, functional annotation of citrus unigenes with Arabidopsis orthologues revealed gene representation in every major functional category, suggesting that a genome-wide EST collection has been obtained. A Citrus clementina genomic library, that will contribute to further characterization of relevant genes, has also been constructed. In addition, a second-generation cDNA microarray, including probes for each of the 25,000 putative unigenes isolated, is under construction, and will soon be available.
The CFGP citrus genome-wide cDNA clone and EST collections, genomic library, and microarrays constitute some of the first high-coverage genomics tools available to carry out genome analysis in citrus. Their use will facilitate the research on function, structure, and regulation of the citrus genome, as well as the isolation of genes of interest for citrus improvement. The clones used to generate the EST collection, the genomic library, and the cDNA microarrays are publicly available and represent a valuable resource for the citrus research community, ensuring that large amounts of data will be collected on the same physical set of resource clones.