Fatty Acid Composition and Expression Analysis of Fatty Acid Biosynthetic Pathway Genes in Developing Seeds of Jatropha Curcas L.
Alternate of fossil fuels are being explored due to diminishing fossil fuel reserves and increasing environmental
degradation. Biodiesel is an alternate of petro-diesel which is made by trans-esterification of vegetable oil or animal fat. Among
the various feedstocks of biodiesel, seed oil from Jatropha curcas is preferred since it is non-edible, has high seed oil content
and can grow in wastelands.The Jatropha curcas seed oil is rich in linoleic acid, rendering the derived biodiesel susceptible to
oxidation.Therefore, modification of fatty acid composition of Jatropha seed is required for making it’s oil suitable for biodiesel
To understand the accumulation of oil in seed, percent oil content, fatty acid composition and expression level variation of fatty
acid synthetic genes were studied at different developmental stages of seed (5 DAP- 35 DAP). The oil content increased from 15
DAP to 25 DAP, remained almost constant at 30 DAP and again increased to reach maximum level of approximately 35% in
mature seed. The fatty acid composition of seed oil was found to vary at different developmental stages, however, oleic and
linoleic acids were the main constituent in mature seed oil accounting for approximately 44% and 35% respectively.
Theexpression analysis of fatty acid synthesis genes using semi-quantitative PCR and qRT-PCR in developing seeds (5 DAP to
35 DAP) was also carried out. The transcript levels of KASI, KASII and SAD genes were found to be maintained at low levels
from 5 DAP to 25 DAP up-regulating subsequently to reach a maximum level at 35 DAP. FAD2 transcript level decreased
between 5 DAP to 25 DAP and then recovered to initial level at 30 DAP and 35 DAP. The FAD3 transcript increased at 10
DAP but declined continuously from 15 DAP to 35 DAP.