Abstract
Patatin-related phospholipases A (pPLAs) are a group of plant-specific acyl lipid hydrolases that share less homology with phospholipases than that observed in other organisms. Out of the three known subfamilies (pPLAI, pPLAII, and pPLAIII), the pPLAIII member of genes is particularly known for modifying the cell wall structure, resulting in less lignin content. Overexpression of pPLAIIIα and ginseng-derived PgpPLAIIIβ in Arabidopsis and hybrid poplar was reported to reduce the lignin content. Lignin is a complex racemic phenolic heteropolymer that forms the key structural material supporting most of the tissues in plants and plays an important role in the adaptive strategies of vascular plants. However, lignin exerts a negative impact on the utilization of plant biomass in the paper and pulp industry, forage digestibility, textile industry, and production of biofuel. Therefore, the overexpression of pPLAIIIγ in Arabidopsis was analyzed in this study. This overexpression led to the formation of dwarf plants with altered anisotropic growth and reduced lignification of the stem. Transcript levels of lignin biosynthesis-related genes, as well as lignin-specific transcription factors, decreased. Peroxidase-mediated oxidation of monolignols occurs in the final stage of lignin polymerization. Two secondary cell wall-specific peroxidases were downregulated following lowered H2O2 levels, which suggests a functional role of peroxidase in the reduction of lignification by pPLAIIIγ when overexpressed in Arabidopsis.
Highlights
The global demand for plant resources for food and fuel consumption has been estimated to increase up to 50% [1]
Our group has previously reported that the genetic engineering of patatin-related phospholipase pPLAIIIα from Arabidopsis and pPLAIIIβ from ginseng by overexpression in Arabidopsis and hybrid poplar reduced the total content of lignin and xylem lignification [3,4,5]
Our previous study showed that overexpression of pPLAIIIα [5] and PgpPLAIIIβ in the Arabidopsis system [3,5] reduced lignin content in the stem of each transformant
Summary
The global demand for plant resources for food and fuel consumption has been estimated to increase up to 50% [1]. Engineering the raw plant materials for valuable biomass is necessary to meet the worldwide energy demand. The cell wall of plant biomass is primarily composed of three biopolymers including cellulose, hemicellulose, and lignin. It includes other minor components such as organic acids, tannins, proteins, and secondary metabolites. The composition of lignocellulosic material varies between different plant species, and sometimes becomes an impediment in developing biomass engineering techniques for bioethanol production [2]. The pretreatment step to separate cellulose from lignin during bioethanol production using plant cell walls is costly. Lignin is a class of complex aromatic biopolymers that provides fundamental structural support to plant cell walls, the presence of lignin is considered the major cause of biomass recalcitrance. The functional roles of other close homologs pPLAIIIγ and pPLAIIIδ focused on lignification were not yet characterized
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
