Genome-wide Identification and Analysis of MVD Gene Family in Euphorbiaceae Plants

摘要

The mevalonate diphosphate decarboxylase(MVD)is an essential enzyme in mevalonate(MVA)pathway that catalyzes the irreversible Mg2+-ATP dependent decarboxylation of 6-carbon compound mevalonate-5-diphosphate(MVAPP)into 5-carbon isopentenyl diphosphate(IPP),the building block of sterol and isoprenoid biosynthesis.In this study,based on the published genome sequences and ESTs,a genome-wide search was carried out for the first time to identify MVD gene family in four genome-sequenced Euphorbiaceae plants,i.e.castor bean(Ricinus communis),physic nut(Jatropha curcas),cassava(Manihot esculenta)and rubber tree(Hevea brasiliensis),and to analyze the gene structure and phylogenetic characteristics.According to the experimental results,1,1,2 and 2 MVD genes,which all contain 9 introns,were identified from castor bean,physic nut,cassava and rubber tree,respectively.Homology analysis indicates that MVD genes are widely distributed in eukaryotes,some archaea and eubacteria,which suggests an early origin of this gene family.Although MVD genes were identified in most green plants,no homologous genes were found in unicellular green algae.In most genome-sequenced plants including castor bean and physic nut,a single copy of MVD gene was found;however,in cassava and rubber tree,two copies were identified just like that in moss,maize,Arabidopsis and poplar.In castor bean,digital expression profiling suggests that in five examined tissues,i.e.leaf,flower,II/III stage endosperm,V/VI stage endosperm and seed,RcPMK was expressed strongly in flower and II/III stage endosperm,moderately in V/VI stage endosperm and leaf,and weakly in seed.