Genomic resources of Euphorbia schimperi : evolutionary and medicinal

Euphorbia schimperi is a toxic plant within the Euphorbiaceae with medicinal applications. The species is known to produce secondary compounds that are effective against breast and brain cancer but very little is currently known about the genomics of E. schimperi. In order to enhance the understanding of phylogenetic relationships with other plants within the same family, the plastid genome (plastome) was sequenced with the aim of understanding its evolution. The results revealed E. schimperi plastome is 159,463 bp in size and it includes a pair of inverted repeats (IR) of 26,629 bp, which are separated by a small single copy (SSC) region of 17,305 bp and a large single copy (LSC) region of 88,900 bp. Euphorbia schimperi plastome has a GC content of 35.6. The total number of protein coding genes is 84 while the total number of genes is 118. In the IR, 19 genes are duplicated and there are 30 and 4 tRNA and rRNA genes, respectively. However, in E. schimperi, the infA, rps16 and rpl32 genes are nonfunctional. The medicinal plant, E. schimperi, accumulates important secondary compounds, such as triterpenoids like cycloart-23-en-3β, 25-diol, α-amyrin, and cycloart-25-en-3β 24-diol as well as steroid glycosides, flavonoids and phenylpropanoids, which are known to have brain and breast anti-cancer properties. In this study, transcriptome sequencing of E. schimperi was conducted to identify the enzymes (genes) that are involved in biosynthesis of these compounds. About 80,916,952 million paired-end sequence reads of 150 bp were generated from RNA isolated from fresh leaf tissue of E. schimperi using IIlumina platform. Gene family trees were constructed to identify homologs of six pathway genes (LUP2, AT4G34050 (CCOAOMT1), FNSI, UGT80A2, RcCAS, and FLS1) to examine their evolutionary relationship. Sequences of all six genes were identified in the transcriptome of E. schimperi and some of them have more copies then the other members of Malpighiales as well as Fabales. The transcriptome study provides valuable information for understanding specialized plant metabolism and genomic resources for increasing the production of plant- derived pharmaceuticals