Abstract
We examined the substrate preference of Cuphea paucipetala acyl-ACP thioesterases, CpFatB4 and CpFatB5, and gene expression changes associated with the modification of lipid composition in the seed, using Brassica napus transgenic plants overexpressing CpFatB4 or CpFatB5 under the control of a seed-specific promoter. CpFatB4 seeds contained a higher level of total saturated fatty acid (FA) content, with 4.3 times increase in 16:0 palmitic acid, whereas CpFatB5 seeds showed approximately 3% accumulation of 10:0 and 12:0 medium-chain FAs, and a small increase in other saturated FAs, resulting in higher levels of total saturated FAs. RNA-Seq analysis using entire developing pods at 8, 25, and 45 days after flowering (DAF) showed up-regulation of genes for β-ketoacyl-acyl carrier protein synthase I/II, stearoyl-ACP desaturase, oleate desaturase, and linoleate desaturase, which could increase unsaturated FAs and possibly compensate for the increase in 16:0 palmitic acid at 45 DAF in CpFatB4 transgenic plants. In CpFatB5 transgenic plants, many putative chloroplast- or mitochondria-encoded genes were identified as differentially expressed. Our results report comprehensive gene expression changes induced by alterations of seed FA composition and reveal potential targets for further genetic modifications.
Highlights
Brassica napus is one of the most-produced oilseed crops in the world, second only to soybean, and is used for human consumption, biodiesel, and industrial raw materials [1]
One-hundred seed weight was increased for CpFatB4 seeds by 10.0%, whereas a 5% decrease was found for CpFatB5 seeds
I)natnhdis1s0t:u0d(2y5umsionlg%tr)aFnAssg,ebnaisceBd. onnapFuAs,pCrpoFfialteBs5inexEpsrcehsesriiochniaalcsooliperxopdreuscseidngmCevdFiuamtB-1c.hIaninthFiAs sst:u1d0:y0uasnidng12tr:0an(Tsgaebnleic1B)..Tnaakpeuns,tCogpFetahtBer5, we demonstrated that CpFatB4 and CpFatB5 function as thioesterases with different biochemical properties using the transgenic approach: the former is mainly involved in the production of 16:0 fatty acid (FA), www.mdpi.com/journal/ijms expression produced medium-chain FAs: 10:0 and 12:0 (Table 1)
Summary
Brassica napus (rapeseed) is one of the most-produced oilseed crops in the world, second only to soybean, and is used for human consumption, biodiesel, and industrial raw materials [1]. The FA compositions of B. napus and other temperate oilseed crops are generally high in unsaturated FAs [2]. Unlike many temperate oilseed crops, the tropical palm tree has a high content of saturated FAs in its oil. The oil palm is an efficient crop, producing up to ten times more oil per hectare than soybean, B. napus, or sunflower, palm trees grow only in the limited area of the tropical zone, and palm oil production leads to tropical deforestation [4]. It would be beneficial to modify the composition of saturated FAs in B. napus growing in the temperate area. The Agrobacterium-mediated transformation method for B. napus is well established, and it allows the manipulation of seed oil composition [5]
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
