Sunflower HaGPAT9-1 is the predominant GPAT during seed development

A - Papers appearing in refereed journals

Paya-Milans, M., Aznar-Moreno, J. A., Balbuena, T. S., Haslam, R. P., Gidda, S. K., Perez-Hormaeche, J., Mullen, R. T., Thelen, J. J., Napier, J. A., Salas, J. J., Garces, R., Martinez-Force, E. and Venegas-Caleron, M. 2016. Sunflower HaGPAT9-1 is the predominant GPAT during seed development. Plant Science. 252 (November), pp. 42-52.

AuthorsPaya-Milans, M., Aznar-Moreno, J. A., Balbuena, T. S., Haslam, R. P., Gidda, S. K., Perez-Hormaeche, J., Mullen, R. T., Thelen, J. J., Napier, J. A., Salas, J. J., Garces, R., Martinez-Force, E. and Venegas-Caleron, M.
Abstract

In oil crops, triacylglycerol biosynthesis is an important metabolic pathway in which glycerol-3-phosphate acyltransferase (GPAT) performs the first acylation step. Mass spectrometry analysis of developing sunflower (Helianthus annuus) seed membrane fractions identified an abundant GPAT, HaGPAT9 isoform 1, with a N-terminal peptide that possessed two phosphorylated residues with possible regulatory function. HaGPAT9-1 belongs to a broad eukaryotic GPAT family, similar to mammalian GPAT3, and it represents one of the two sunflower GPAT9 isoforms, sharing 90% identity with HaGPAT9-2. Both sunflower genes are expressed during seed development and in vegetative tissues, with HaGPAT9-1 transcripts accumulating at relatively higher levels than those for HaGPAT9-2. Green fluorescent protein tagging of HaGPAT9-1 confirmed its subcellular accumulation in the endoplasmic reticulum. Despite their overall sequence similarities, the two sunflower isoforms displayed significant differences in their enzymatic activities. For instance, HaGPAT9-1 possesses in vivo GPAT activity that rescues the lethal phenotype of the cmy228 yeast strain, while in vitro assays revealed a preference of HaGPAT9-1 for palmitoyl-, oleoyl- and linoleoyl-CoAs of one order of magnitude, with the highest increase in yield for oleoyl- and linoleoyl-CoAs. By contrast, no enzymatic activity could be detected for HaGPAT9-2, even though its over-expression modified the TAG profile of yeast.

Year of Publication2016
JournalPlant Science
Journal citation252 (November), pp. 42-52
Digital Object Identifier (DOI)doi:10.1016/j.plantsci.2016.07.002
Open accessPublished as bronze (free) open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeDesigning Seeds for Nutrition and Health (DS)
*Design Oilseeds (Olga Sayanova)
Publisher's version
File Access Level
Open
Output statusPublished
Publication dates
Online09 Jul 2016
Publication process dates
Accepted07 Jul 2016
ISSN0168-9452
PublisherElsevier Ireland Ltd

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