https://jopr.mpob.gov.my Wed, 17 Nov 2021 07:19:31 +0000 en-US hourly 1 https://wordpress.org/?v=7.0 https://jopr.mpob.gov.my/determining-the-optimal-concentration-of-mannose-as-an-effective-selection-agent-for-transformed-oil-palm-cells-using-the-phosphomannose-isomerase-pmi-gene-as-a-positive-selectable-marker/ Sat, 13 Nov 2021 08:03:01 +0000 https://jopr.mpob.gov.my/V2/?p=9027 The elimination of antibiotic or herbicide resistance gene usage in genetically modified plants is being encouraged due to public concern. In response to this, alternative selection systems for the recovery of transgenic oil palm were developed using positive selectable markers. To establish a selection system that utilises the phosphomannose isomerase (pmi) gene for oil palm transformation, we first determined the optimal mannose concentration for selecting the transformed cells. Non-transformed embryogenic calli were cultured on media containing various combinations and concentrations of mannose and a usable source of carbon, i.e. sucrose, ranging in content from 0 to 30 g litre^-1. Sucrose is often used as a carbon source in plant tissue culture media. The embryogenic calli were subcultured onto similar fresh media every four weeks, and growth was recorded monthly up to five months. From the 10 combinations of mannose and sucrose evaluated, mannose:sucrose at 30:0 g litre^-1 was shown to be the most effective for selection because at this concentration the least plant growth was demonstrated for non-transformed embryogenic calli. We will thereafter use this particular concentration of mannose to select for oil palm embryogenic calli transformed with the pmi gene using biolistic bombardment.

]]> https://jopr.mpob.gov.my/optimisation-of-2-deoxyglucose-concentration-for-identifying-the-sensitivity-level-for-oil-palm-embryogenetic-calli/ Sat, 13 Nov 2021 08:03:01 +0000 https://jopr.mpob.gov.my/V2/?p=9022 In this study, the sensitivity of oil palm calli to 2-deoxyglucose (2-DOG) was evaluated to determine the optimal concentration to be used as a selection agent for oil palm embryogenic calli. It was reported earlier that 2-DOG has been used for selecting transformants using the DOGR1 gene which encodes 2-deoxyglucose-6-phosphate (2-DOG-6-P) phosphatase. In plants, 2-DOG is converted into 2-DOG-6-P by endogenous hexokinase which results in the inhibition of cell growth. Therefore, an experiment to determine the optimal concentration of 2-DOG required to fully inhibit the regeneration of untransformed oil palm embryogenic calli was carried out. The untransformed embryogenic calli were cultured on embryogenic callus (EC) medium supplemented with different concentrations of 2-DOG, ranging from 0 to 1000 mg litre^-1. Results show that 400 mg litre^-1 of 2-DOG led to nearly complete inhibition (>80%) of oil palm embryogenic calli regeneration. This was demonstrated by a reduction in the calli weight and in the ability to form whitish embryoids. This optimal concentration of 2-DOG is recommended to be used for the selection and regeneration of transformed oil palm embryogenic calli after transformation using the DOG^R1 gene in future experiments.

]]>