Plant & Animal Genomes XIV Conference

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

Analysis Of The Complete Chloroplast Genome Of Citrus sinensis

M G Bausher¹ , J Mozoruk¹ , S-B Lee² , N Singh² , R K Jansen³ , H Daniell²

¹  US Department of Agriculture,Agricultural Research Service, 2001 South Rock Road, Fort Pierce, FL 34945-3030 USA

²  University of Central, Department of Molecular Biology & Microbiology, Biomolecular Science, Building #20, Orlando, FL 32816-2364 USA

³  Section of Integrative Biology and Institute of Cellular and Molecular Biology, Patterson Laboratories 141, University of Texas, Austin TX 78712 USA

The genus Citrus is the most economically significant fruit crop in the U.S. and the world. Its worldwide production was 19 million metric tons in 2002. Little is know about citrus chloroplast genome. The complete nucleotide sequence of the chloroplast genome of Citrus sinensis L Osbeck var ¡®Ridge Pineapple¡¯ has been determined. The genome is 160,614 bp long. The genome includes a pair of inverted repeats of 26,136 bp separated by a small and large single copy regions of 18,942 bp and 89,400 bp, respectively. There are 113 unique genes and 20 genes are duplicated in inverted repeat regions giving a total of 133 genes. Among this, 89 genes, including 9 genes duplicated in the inverted region, code for proteins. There are 4 ribosomal RNA genes and 30 distinct tRNAs, 7 of which are duplicated in the inverted repeat regions. Seventeen genes have introns, 15 with one intron and two with 2 introns. The gene order is identical to the available genome sequences of the Solanaceae family. However, the infA gene is absent in the citrus genome. Repeat analysis identified 34 direct and inverted repeats 30 bp or longer with a sequence identity ¡Ý 90%. Comparison of protein coding sequences with expressed sequence tags (ESTs) is in progress. Phylogenetic analysis of the protein coding genes are being performed to assess the relationship of citrus to the 30 other sequenced angiosperm chloroplast genomes. Availability of the complete chloroplast genome sequence should facilitate chloroplast genetic engineering of Citrus.