Proteomic Analysis of the Endosperm Ontogeny of Jatropha curcas L. Seeds

Seeds
of Jatropha curcas L. represent
a potential source of raw material for the production of biodiesel.
However, this use is hampered by the lack of basic information on
the biosynthetic pathways associated with synthesis of toxic diterpenes,
fatty acids, and triacylglycerols, as well as the pattern of deposition
of storage proteins during seed development. In this study, we performed
an in-depth proteome analysis of the endosperm isolated from five
developmental stages which resulted in the identification of 1517,
1256, 1033, 752, and 307 proteins, respectively, summing up 1760 different
proteins. Proteins with similar label free quantitation expression
pattern were grouped into five clusters. The biological significance
of these identifications is discussed with special focus on the analysis
of seed storage proteins, proteins involved in the metabolism of fatty
acids, carbohydrates, toxic components and proteolytic processing.
Although several enzymes belonging to the biosynthesis of diterpenoid
precursors were identified, we were unable to find any terpene synthase/cyclase,
indicating that the synthesis of phorbol esters, the main toxic diterpenes,
does not occur in seeds. The strategy used enabled us to provide a
first in depth proteome analysis of the developing endosperm of this
biodiesel plant, providing an important glimpse into the enzymatic
machinery devoted to the production of C and N sources to sustain
seed development.