Quantitative profiling of mono- and polyglutamyl folates in rice was achieved using the microbiological assay (MA) and a newly developed liquid chromatography tandem mass spectrometry (LC-MS/MS) method. MA was used to screen 51 rice cultivars for their total folate content and LC-MS/MS was employed to measure naturally occurring mono- and polyglutamated forms of the vitamin in wild type, FPGS Os03g02030 knockout and transgenic lines with overexpressed FPGS genes and with folate binding protein from cow’s milk (cFBP) and rat’s liver (GNMT). Natural variation among rice cultivars in terms of total folate content was measured using MA screening and the validated LC-MS/MS technique of simultaneous profiling of mono- and polyglutamated folates through MeOHAA/PO4 extraction revealed that the naturally-occurring species in wild type rice are 5-CH3-H4PteGlu, 5/10-CHO-H4PteGlu, 5-CH3-H4PteGlu4, 5-CH3-H4PteGlu5 and 5/10-CHO-PteGlu5. There was a general decrease in these folate forms in the FPGS Os03g02030 knockout rice line while a dramatic increase was observed in overexpressed FPGS, cFBP and GNMT compared to Nipponbare in terms of 5-CH3-H4PteGlu4, 5/10-CHO-H4Pteglu5, 5-CH3-H4PteGlu6, and 5/10-CHO-H4Pteglu6 levels, resulting in a 2.5 to 8.8-fold increase in the total folate pool in the unpolished grains of rice. This study looked at the role of the two FPGS genes (Os03g02030 and Os10g35940) found in rice and the possible effect of introducing folate binding proteins (cFBP and GNMT) in terms of the overall folate profile in rice which can be exploited in breeding programmes designed to enhance folate content in staple crops like rice.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:519912 |
| Date | January 2010 |
| Creators | Abilgos Ramos, Riza |
| Publisher | University of Nottingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://eprints.nottingham.ac.uk/12870/ |
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