Gene coexpression network for <i>trans</i>-1,4-polyisoprene biosynthesis involving mevalonate and methylerythritol phosphate pathways in <i>Eucommia ulmoides</i> Oliver

Abstract

Eucommia ulmoides, a deciduous dioecious plant species, accumulates trans-1,4-polyisoprene (TPI) in its tissues such as pericarp and leaf. Probable TPI synthase (trans-isoprenyl diphosphate synthase (TIDS)) genes were identified by expressed sequence tags of this species; however, the metabolic pathway of TPI biosynthesis, including the role of TIDSs, is unknown. To understand the mechanism of TPI biosynthesis at the transcriptional level, comprehensive gene expression data from various organs were generated and TPI biosynthesis related genes were extracted by principal component analysis (PCA). The metabolic pathway was assessed by comparing the coexpression network of TPI genes with the isoprenoid gene coexpression network of model plants. By PCA, we dissected 27 genes assumed to be involved in polyisoprene biosynthesis, including TIDS genes, genes encoding enzymes of the mevalonate (MVA) pathway and the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway, and genes related to rubber synthesis. The coexpression network revealed that 22 of the 27 TPI biosynthesis genes are coordinately expressed. The network was clustered into two modules, and this was also observed in model plants. The first module was mainly comprised of MEP pathway genes and TIDS1 gene, and the second module, of MVA pathway genes and TIDS5 gene. These results indicate that TPI is likely biosynthesized by both the MEP and MVA pathways and that TIDS gene expression is differentially controlled by these pathways.

Natural Polymer Eucommia Ulmoides Rubber: A Novel Material

“…ulmoides Oliver. With the development of technology and research, the biosynthetic pathway, gene controlling biosynthesis, and genomic and genetic bases of EUR have been widely studied. ,− In the early steps of EUR biosynthesis, it was thought that the isopentenyl diphosphate (IPP) was synthesized by the 2-C-methyl- d -erythritol-4-phosphate (MEP) pathway and/or cytosolic mevalonate (MVA) pathway . However, by Pearson correlation analysis, Wuyun et al found that expression patterns of genes in the MEP pathway were not correlated with the accumulation of EUR .…”

Biosynthesis of Natural Rubber: Current State and Perspectives

“…Farnesyl diphosphate synthases (FPSs) were identified and demonstrated to be the main prenyltransferase involved in trans -1,4-polyisoprene (Eu-rubber) biosynthesis in E. ulmoides [5,6,89]. Gene co-expression network analysis showed correlated expression pattern of MEP pathway genes with EuFPS1 and MVA pathways genes with EuFPS5 , indicating that both MEP and MVA pathways may be involved in Eu-rubber biosynthesis [90]. However, expression patterns of MEP pathway genes were not correlated with the accumulation of Eu-rubber in fruits, while MVA pathway genes did, implying that MVA pathway rather than MEP pathway is mainly responsible for IPP supply during Eu-rubber biosynthesis in fruits [5].…”