https://jopr.mpob.gov.my Wed, 30 Mar 2022 01:58:13 +0000 en-US hourly 1 https://wordpress.org/?v=7.0 https://jopr.mpob.gov.my/morpho-physiological-assessment-of-oil-palm-elaeis-guineensis-jacq-seedlings-exposed-to-simulated-drought-conditions-2/ Tue, 29 Mar 2022 01:05:47 +0000 https://jopr.mpob.gov.my/V2/?p=10747 Elaeis guineensis Jacq. (oil palm) production is threatened by drought due to climate change and anthropogenic deforestation. This study aims to understand how drought conditions contribute to changes in foliar nitrate-nitrogen concentration as well as the effects on the growth and development of oil palm seedlings. Seventy oil palm seedlings were maintained in a screen house and subjected to simulated drought conditions. There was a significant reduction in the number of leaves with increased drought exposure from 10 to four per plant. Oil palm leaves exposed to higher drought levels had less broad leaves, with leaf area ranging from 133.25-172.22 cm² compared to the control (383.73 cm²). The foliar yield per plant was low in plants exposed to extreme drought condition (2.27 g), compared to 71.98 g in the control. Moreover, total drought-exposed oil palm seedlings had the highest concentration of nitrate-nitrogen. E. guineensis exposed to no-drought conditions had more roots (18 roots) than those exposed to total or partial drought (6-10 roots per plant). Overall, there was a decrease in height, leaf area and the number of leaves for most of the seedlings exposed to drought condition, which might be detrimental to their photosynthetic ability and growth.

]]> https://jopr.mpob.gov.my/biochemical-studies-and-purificationof-oil-palm-elaeis-guineensis-jacq-%ce%b2-ketoacyl-acyl-carrier-protein-acp-synthesis-kas-ii-enzyme/ Sat, 13 Nov 2021 08:03:40 +0000 https://jopr.mpob.gov.my/V2/?p=9033 The rapid increase in palm oil production over the last 20 years has made this oil the most important in the world. Palm oil produced in the mesocarp of the oil palm (Elaeis guineensis) fruit contains primarily palmitic (44%) and oleic (39%) acids with only a small proportion of polyunsaturated fatty acids. As a prelude to detailed biochemical analysis of the fatty acid biosynthesis of oil palm, we examined β-ketoacyl-ACP synthase (KAS) II activity, and evidence is presented on its importance in palmitic acid accumulation. In this study, three different oil palm breeding materials were screened for KAS II and fatty acid compositions. Collectively, the results strongly suggest that KAS II plays an important role in determining the relative amounts of C16 and C18 fatty acids in oil palm. KAS II activity was profiled through various stages of fruit development from 12 to 22 weeks after anthesis (WAA). The data depicted a pattern of progressive increase in KAS II activity similar to that of triacylglycerol synthesis in the oil palm mesocarp which started at 15 WAA and reached a maximum around 20 WAA. The enzyme was purified to homogeneity (>9000-fold purification) using a combination of ion exchange on CM-Sepharose, HR-DEAE, hyroxyapatite and affinity chromatography (ACP-Sepharose). Activity of the purified enzyme was inhibited by the chelating agent ethylene diamine tetra-acetate (EDTA) (1 M), but the inhibitory action could be overcome by divalent cations such as Mn²⁺ or Mg²⁺ (10 mM). Optimal activity was observed at pH 4.5. The data represent the first contribution to the biochemical characterisation of oil palm KAS II activity associated with fatty acid biosynthesis.

]]> https://jopr.mpob.gov.my/the-isolation-and-characterisation-of-oil-palm-elaeis-guineensis-jacq-%ce%b2-ketoacy-acyl-carrier-protein-acp-synthase-kas-ii-cdna/ Sat, 13 Nov 2021 08:04:16 +0000 https://jopr.mpob.gov.my/V2/?p=9056 Modulating endogenous levels and/or producing novel fatty acids of oils have gained significant attention in recent years to meet the demand for oils for specific markets. The commodity palm oil is composed mainly of four fatty acids: palmitic acid (16:0), stearic acid (18:0), oleic acid (18:1) and linoleic acid (18:2). The percentages of these fatty acids in palm oil average 44%, 4%, 39% and 10%, respectively, with trace amounts of other fatty acids. Metabolic engineering may be used to produce oil crops with desired fatty acid compositions. We have isolated and characterised β-ketoacyl ACP-synthase II (KASII) cDNA from oil palm (Elaeis guineensis) which is one of the main components for the oil palm genetic engineering programme. KAS II is associated with the accumulation of palmitic acid in oil palm, and its role in controlling the ratio of C16:C18 has been previously determined. We isolated KAS II cDNA from oil palm, and functionally characterised the same in Escherichia coli and Arabidopsis. Partial length KAS II cDNA was first obtained by the reverse transcriptase-polymerase chain reaction (RT-PCR). Rapid amplification of cDNA ends (RACE) was then used to isolate both the 5’ and 3’ ends of the KAS II sequences. Assembly of the partial length sequence fragments, including the 5’ and 3’ ends, allowed for the full-length sequence information on the KAS II cDNA to be obtained and used in the gene isolation. Expression studies in E. coli resulted in an increase in oleic acid at the expense of palmitic acid. Arabidopsis thaliana was also used to further confirm the functional activity of the oil palm KAS II. A significant decrease in C18:0 and accumulation of C16:0 were detected in the plants that had been transformed with the antisense KASII construct. This suggests that the substrate specificity of the oil palm KAS II is similar to that of KAS II from other plants which preferentially elongate palmitic to stearic acids. The oil palm KAS II may, therefore, be useful in providing new opportunities in the genetic engineering programme for the production of high-value products such as an oil with a high content of monounsaturated fatty acids from the transgenic oil crops.

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