Can N nutrition lead to "plant diabetes"? The perspective from ammonium nutrition and methylglyoxal accumulation

Here we introduce a debate about whether plants can be suffering a "diabetes-like syndrome" depending on the N nutrition management. The idea of a plant diabetes is not new and was initially proposed by Saito et al. (2011) when they identified MG as a potent photosystem I-mediated superoxides generator in spinach chloroplasts. Later and along the same lines, Takagi et al. (2014) and Shimakawa et al. (2014) discussed the possible plant diabetes by associating it with the accumulation of MG as a common metabolite of the primary pathways of sugar anabolism and catabolism. Nevertheless, given the increasing relevance of NH+ 4 nutrition for crop production in a context of elevated atmospheric CO2, in addition to being a less polluting alternative to the excessive use of NO- 3 (Subbarao and Searchinger, 2021), we examine here from a new point of view the current knowledge about the glycolytic by-product MG and its link to a possible "NH+ 4 diet"-mediated plant diabetes.