Genetic, biochemical, and metabolomic analysis of plant purine catabolism

• Applicant: Professor Dr. Claus-Peter Witte
• Subject Area: Plant Biochemistry and Biophysics
• Term: from 2008 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 60413419

A profound understanding of plant nitrogen (N) remobilisation is needed to improve crop nitrogen use efficiency. Crops that make optimal use of their N resources require less fertilisation which reduces costs and hazardous effects to the environment. Purine nucleotide degradation contributes to N remobilisation in plants but several enzymes of this pathway have not been identified genetically yet. We propose to (i) identify and characterise “missing” enzymes in purine degradation in arabidopsis and soybean, (ii) investigate the physiological and metabolic effects of altered purine degradation in arabidopsis and soybean using a range of mutants, transient knock-down plants, and over-expression lines. Growth, N remobilisation, and metabolite profiles will be measured. The regulation of purine catabolism on transcriptional and post-transcriptional level will be determined in different physiological situations. Accumulation of purine degradation intermediates can have toxic effects (in the case of urate) or be beneficial to the plant (in case of allantoin) and then be a desired metabolic output in certain stress situations. Using arabidopsis plants altered in allantoin content we will investigate the physiological role of this compound in senescence, salt and osmotic stress. A uricase mutant of arabidopsis will be employed to investigate urate toxicity on cellular and molecular level in plants. Potentially these studies will also permit new insights into urate toxicity in humans leading to diseases like gout and Lesch Nyhan syndrome.

• DFG Programme: Research Grants