Fig. 9

Proposed model of methylglyoxal detoxification via glyoxalase pathway proteins in various subcellular organelles of sorghum. Cellular defence against MG probably involves four different sub-cellular compartments viz. cytosol, chloroplast, mitochondria and nucleus. Cytosolic MG produced as an off shoot of glycolysis is converted to SLG by SbGLYI-10/11 which is further converted to D-lactate by SbGLYII-3. The conversion of D-lactate to pyruvate is catalysed either by SbDLDH-3, 4.1 or 4.2. Both in the mitochondria as well as chloroplast, MG detoxification is predicted to be catalysed by the same SbGLYI and SbGLYII proteins. D-lactate produced in the chloroplast can be converted to pyruvate either by cytosolic SbDLDH protein or transported in the mitochondria. In mitochondria, D-lactate is converted to pyruvate by SbDLDH-1/2 protein. Pyruvate is then fed into the Kreb’s cycle. In the nucleus, SbGLYI-8/SbGLYI-8.1, may catalyse the conversion of MG to SLG. Nuclear export of SLG is proposed as no nuclear GLYII could be predicted in the sorghum genome. TPI-Triose phosphate isomerase, GSH-Glutathione, G3P-Glyceraldehyde-3-Phosphate, F-1,-6-BP- Fructose-1,6-bisphosphate, Ru-1,5-BP- Ribulose-1,5, bisphosphate, PGA- Phosphoglyceraldehyde