WRINKLED1 transcription factor orchestrates the regulation of carbon partitioning for C18:1 (oleic acid) accumulation in Siberian apricot kernel

Abstract

WRINKLED1 (WRI1), an APETALA2 (AP2)-type transcription factor, has been shown to be required for the regulation of carbon partitioning into fatty acid (FA) synthesis in plant seeds. To our knowledge, the regulatory network of WRI1 remains unknown in Prunus sibirica kernel (PSK), a novel woody biodiesel feedstock in China. In this study, based on the transcriptional data from developing oilseeds of multiple plant species, we identified 161 WRI1 -coexpressed genes using weighted gene co-expression network analysis (WGCNA). The major portion of WRI1 -coexpressed genes was characterized to be involved in carbon partitioning and FA biosynthesis. Additionally, we detected the temporal patterns for oil content and FA compositions in developing PSK from two different germplasms (AS-85 and AS-86). The major differences between the two germplasms are higher contents of oil and C18:1 in AS-85 than in AS-86 at a mature stage. Thus, AS-85 and AS-86 are desirable materials to explore the molecular and metabolic mechanisms of oil accumulation in Siberian apricot. Expression analysis in developing PSK of AS-85 and AS-86 indicated that the expression level of P . sibirica WRI1 (PsWRI1) was closely correlated to accumulative rate of oil. Also, the comparison of expression profiles in developing PSK of AS-85 and AS-86 displayed that the pPK , E1-α , E2 , TAL , BC , MCMT , BS , SAD and FAD2 have a high correlation with PsWRI1 . Transient expression showed that Pro SAD - and Pro BS -driving GUS expression showed no substantial difference between AS-85 and AS-86, while the expression level of Pro PEPCK -AS-85 driving GUS was significantly higher than that of Pro PEPCK -AS-86 driving GUS. Additionally, transient co-transformation with PsWRI1 revealed that Pro SAD , Pro PEPCK and Pro BS activity could be specifically up-regulated by PsWRI1. This regulatory mechanism of PsWRI1 may create a steep concentration difference, thereby facilitating carbon flux into C18:1 accumulation in developing PSK. Overall, all our findings imply a versatile mechanism of WRI1 to optimize carbon allocation for oil accumulation, which can provide reference for researching the woody biodiesel plants.

Transcriptome analysis of metabolic pathways associated with oil accumulation in developing seed kernels of Styrax tonkinensis, a woody biodiesel species

“…In this study, expression patterns for ABI3, ABI4, HSI2/VAL1, L1L, PKL, and WRI1 suggest that they play positive roles in regulating genes for oil biosynthesis, while other TFs may act as negative or ambiguous regulatory factors. Among them, WRI1 displayed a coordinated transcriptional profile with pk, pdc, acc, kas, sad, and fad2, consistent with its function as a central regulator that directs carbon flux from glycolysis into FA biosynthesis during seed oil accumulation [65,66]. Similar results were seen in previous investigations on E. guineensis and P. sibirica [28,29].…”

Genome-Wide Screening of AP2 Transcription Factors Involving in Fruit Color and Aroma Regulation of Cultivated Strawberry

“…WRI TFs regulate oil biosynthesis by providing precursors (acyl chain and glycerol backbones) for various lipid biosynthetic pathways in both seed oil and flower or fruit surface waxes [ 14 , 15 , 34 ]. However, the roles of WRI TFs in fruit aroma have not been studied.…”

Gene expression profiling identifies pathways involved in seed maturation of Jatropha curcas

“…Among TFs related to seed oil accumulation, we could identify differentially expressed transcripts that showed homology to Arabidopsis AP2 type TFs, WRI1 and HD-ZIP type, GLABRA2 (Table S5). The WRI1 has been studied extensively in the regulation of the transcription levels of genes in lipid biosynthesis pathways in the Arabidopsis, rapeseed, maize, potato, Siberian apricot kernel, and Jatropha seeds [24,[65][66][67][68][69]. It was reported that overexpression of JcWRI1 not only increased the lipid content but also the seeds mass.…”