The Ureide-Degrading Reactions of Purine Ring Catabolism Employ Three Amidohydrolases and One Aminohydrolase in Arabidopsis, Soybean, and Rice

Plant Purine Nucleoside Catabolism Employs a Guanosine Deaminase Required for the Generation of Xanthosine in Arabidopsis

“…The unaltered growth of the gsda mutants indicates that the lack of guanosine catabolism does not strongly affect plant growth and development when plants are kept under standard laboratory and greenhouse conditions. Consistent with this, other mutants of purine nucleoside or purine ring catabolic genes do not show phenotypes under such conditions (Riegler et al, 2011;Werner et al, 2013), but some are affected when exposed to several days of darkness (Brychkova et al, 2008;Jung et al, 2011).…”

Uric Acid Accumulation in an Arabidopsis Urate Oxidase Mutant Impairs Seedling Establishment by Blocking Peroxisome Maintenance

“…The absence of the UOX protein per se or the defective purine ring catabolism, therefore, is not responsible for the developmental defects of the uox mutant. In accordance, a defect in other enzymes of purine ring catabolism does not cause marked phenotypes under standard growth conditions (Yang and Han, 2004;Todd and Polacco, 2006;Brychkova et al, 2008;Werner et al, 2008Werner et al, , 2013. The severity of the uox mutant phenotype varied in intensity depending on the seed batch and to a lesser extent also within the same seed batch, but it was always clearly visible (Supplemental Figure 2).…”

“…Humans do not possess a functional UOX; therefore, the final product of human purine ring catabolism is uric acid, which is excreted in the urine. In plants, S-allantoin catabolism in the endoplasmic reticulum results in the complete decomposition of the purine ring system, releasing carbon dioxide, glyoxylate, and all ring nitrogen as ammonia (Serventi et al, 2010;Werner et al, 2010Werner et al, , 2013 Figure 1). Genetic disruption of purine nucleobase catabolism in Arabidopsis thaliana, preventing the release of the ring nitrogen as ammonia, does not lead to obvious phenotypic alterations under standard growth conditions (Yang and Han, 2004;Todd and Polacco, 2006;Brychkova et al, 2008;Werner et al, 2008Werner et al, , 2013.…”

Of the nine cytidine deaminase like genes in Arabidopsis thaliana eight are pseudogenes and only one is required to maintain pyrimidine homeostasis in vivo

“…In soybean, many genes are present in multiple copies that, in other plants, are only required in a single copy (Polacco et al, 2011;Werner et al, 2013). Soybean is a paleopolyploid plant whose genome underwent polyploidization at least twice, the last time relatively recently (Kim et al, 2009).…”