| Method |
P.1846 left column 3rd paragraph: "[Investigators] profiled CBC metabolites in four C4 species from the NADP-malic enzyme subtype including two monocots (Zea mays and Setaria viridis) and two eudicots (Flaveria bidentis and F. trinervia), and five C3 species including two monocots (Oryza sativa, Triticium aestivum) and three eudicots (Arabidopsis thaliana, Nicotiana tabacum, and Manihot esculenta). Each species was grown with non-saturating irradiance (range of 60–133% of that required for half-maximal rates of photosynthesis) and appropriate temperature for rapid, healthy growth, and harvested under growth irradiance at least 2 h after the beginning of the light period (for details, see Supplementary Table S1). CBC intermediates and 2PG levels were determined by LC-MS/MS, using isotope-labelled internal standards to obtain reliable quantification, or enzymatically (3PGA). The signals for ribulose-5-phosphate (Ru5P) and xylulose-5-phosphate (Xu5P) overlapped, so they were combined (‘Ru5P+Xu5P’). Otherwise, [investigators] were able to quantify all CBC intermediates except 1,3-bisphosphoglycerate, glyceraldehyde 3-phosphate, and erythrose 4-phosphate. Metabolites were initially normalized on FW." |
| Comments |
P.1846 left column bottom paragraph: "CBC metabolite levels varied greatly between species (Fig. 1, Supplementary Dataset S1). This involved differences in the absolute and the relative levels of metabolites. Some of the observed changes were expected, for example the low levels of 2PG in C4 compared with C3 species, reflecting the lower rate of photorespiration in the C4 plants (note, 2PG amounts are multiplied by 10 for better visualization in Fig. 1). RuBP levels were lower in C4 compared with C3 species, probably reflecting lower abundance of RuBisCO in C4 plants." |