Factors affecting polyhydroxybutyrate accumulation in mesophyll cells of sugarcane and switchgrass

McQualter, Richard B., Somleva, Maria N., Gebbie, Leigh K., Li, Xuemei, Petrasovits, Lars A., Snell, Kristi D., Nielsen, Lars K. and Brumbley, Stevens M. (2014) Factors affecting polyhydroxybutyrate accumulation in mesophyll cells of sugarcane and switchgrass. BMC Biotechnology, 14 1: 83.1-83.11. doi:10.1186/1472-6750-14-83

Author McQualter, Richard B.
Somleva, Maria N.
Gebbie, Leigh K.
Li, Xuemei
Petrasovits, Lars A.
Snell, Kristi D.
Nielsen, Lars K.
Brumbley, Stevens M.
Title Factors affecting polyhydroxybutyrate accumulation in mesophyll cells of sugarcane and switchgrass
Journal name BMC Biotechnology   Check publisher's open access policy
ISSN 1472-6750
Publication date 2014-09-10
Sub-type Article (original research)
DOI 10.1186/1472-6750-14-83
Open Access Status DOI
Volume 14
Issue 1
Start page 83.1
End page 83.11
Total pages 11
Place of publication London, United Kingdom
Publisher BioMed Central
Collection year 2015
Formatted abstract
Background: Polyhydroxyalkanoates are linear biodegradable polyesters produced by bacteria as a carbon store and used to produce a range of bioplastics. Widespread polyhydroxyalkanoate production in C4 crops would decrease petroleum dependency by producing a renewable supply of biodegradable plastics along with residual biomass that could be converted into biofuels or energy. Increasing yields to commercial levels in biomass crops however remains a challenge. Previously, lower accumulation levels of the short side chain polyhydroxyalkanoate, polyhydroxybutyrate (PHB), were observed in the chloroplasts of mesophyll (M) cells compared to bundle sheath (BS) cells in transgenic maize (Zea mays), sugarcane (Saccharum sp.), and switchgrass (Panicum virgatum L.) leading to a significant decrease in the theoretical yield potential. Here we explore various factors which might affect polymer accumulation in mesophyll cells, including targeting of the PHB pathway enzymes to the mesophyll plastid and their access to substrate.

Results: The small subunit of Rubisco from pea effectively targeted the PHB biosynthesis enzymes to both M and BS chloroplasts of sugarcane and switchgrass. PHB enzyme activity was retained following targeting to M plastids and was equivalent to that found in the BS plastids. Leaf total fatty acid content was not affected by PHB production. However, when fatty acid synthesis was chemically inhibited, polymer accumulated in M cells.

Conclusions: In this study, we provide evidence that access to substrate and neither poor targeting nor insufficient activity of the PHB biosynthetic enzymes may be the limiting factor for polymer production in mesophyll chloroplasts of C4 plants.
Keyword Acetyl-CoA
C4 grasses
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
Australian Institute for Bioengineering and Nanotechnology Publications
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 2 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 5 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Tue, 07 Oct 2014, 00:19:59 EST by System User on behalf of Aust Institute for Bioengineering & Nanotechnology