Overexpression of a Prefoldin β subunit gene reduces biomass recalcitrance in the bioenergy crop Populus

Abstract

Summary Prefoldin (PFD) is a group II chaperonin that is ubiquitously present in the eukaryotic kingdom. Six subunits (PFD1‐6) form a jellyfish‐like heterohexameric PFD complex and function in protein folding and cytoskeleton organization. However, little is known about its function in plant cell wall‐related processes. Here, we report the functional characterization of a PFD gene from Populus deltoides, designated as PdPFD2.2. There are two copies of PFD2 in Populus, and PdPFD2.2 was ubiquitously expressed with high transcript abundance in the cambial region. PdPFD2.2 can physically interact with DELLA protein RGA1_8g, and its subcellular localization is affected by the interaction. In P. deltoides transgenic plants overexpressing PdPFD2.2, the lignin syringyl/guaiacyl ratio was increased, but cellulose content and crystallinity index were unchanged. In addition, the total released sugar (glucose and xylose) amounts were increased by 7.6% and 6.1%, respectively, in two transgenic lines. Transcriptomic and metabolomic analyses revealed that secondary metabolic pathways, including lignin and flavonoid biosynthesis, were affected by overexpressing PdPFD2.2. A total of eight hub transcription factors (TFs) were identified based on TF binding sites of differentially expressed genes in Populus transgenic plants overexpressing PdPFD2.2. In addition, several known cell wall‐related TFs, such as MYB3, MYB4, MYB7, TT8 and XND1, were affected by overexpression of PdPFD2.2. These results suggest that overexpression of PdPFD2.2 can reduce biomass recalcitrance and PdPFD2.2 is a promising target for genetic engineering to improve feedstock characteristics to enhance biofuel conversion and reduce the cost of lignocellulosic biofuel production.

Transcriptional and Post-transcriptional Regulation of Lignin Biosynthesis Pathway Genes in Populus

“…Potri.012G006400 COMT COMT2 Caffeic acid, caffeoyl-CoA, caffeoyl aldehyde, caffeoyl alcohol lignin content in transgenic poplar (Zhang et al, 2019a). Overexpression of a prefoldin chaperonin β subunit gene PdPFD2.2 increases lignin S/G ration in poplar (Zhang et al, 2019b). This suggests that the molecular regulation of lignin biosynthesis is not unidirectional and is more complex than that was previously reported.…”

Prefoldin Function in Cellular Protein Homeostasis and Human Diseases

“…Unlike prokaryotes, eukaryotes and archaea have another chaperone-assisted protein ( Sahlan et al, 2018 ). Prefoldin is a co-chaperone of TRiC/CCT ( Millan-Zambrano and Chavez, 2014 ; Zhang J. et al, 2020 ). It is a heterohexameric protein complex ( Glover and Clark, 2015 ) that is composed of two α subunits (PFD3 and PFD5) and four β subunits [PFD1, PFD2, PFD4, and PFD6; ( Siegert et al, 2000 ; Whitehead et al, 2007 ).…”

Lectin Receptor-like Kinase Signaling during Engineered Ectomycorrhiza Colonization

“…BiFC assay was performed in Populus protoplasts as described by Zhang et al, 2020 [ 23 ]. In brief, the CDSs of PtLecRLK1 and its substrate candidate proteins were cloned into CFP c (pUC119-CD3-1068) and VENUS n (pUC119-CD3-1076) vectors through Gateway cloning, respectively.…”