Enhanced Nutritional Quality By Glutamate Synthesized By Transgenes Improves Crop Growth, Herbicide Tolerance and Reduced Fungal Toxin Contaminations.

Maize (Zea mays L.) and other crop plants have altered transcript and metabolic profiles caused by in planta expression of the bacterial glutamate dehydrogenase (GDH; EC 1.4.1.2), encoded by a modified gdhA. Labeling experiments showed glutamate produced in the cytoplasm was increased 2 fold, but only by 5% in the chloroplast. The change in glutamate concentration in the cytoplasmic pool has profound effects on metabolism and homeostasis. The metabolic changes resulted in phenotypic changes that included increases in; mean plant biomass production in dry soils; nutritional value; tolerance to the herbicide phosphinothricin; and tolerance to both severe and mild water deficit improved NUE and WUE. Crosses to waxy, flinty and brown-midrib maize were made. Nutritional quality was further improved. Comparisons of transgenic and non-transgenic maize showed a 11% increase in WUE and 9% increase in NUE across a range of water delivery rates. Resistance to rotting necrotrophs including carcinogenic Aspergillus flavus and Fusarium virguliforme was noted. Sporulation of A. flavus was inhibited. The abundance of 747 fungal and 395 maize grain transcripts were altered suggesting the GDH maize was not supporting normal fungal growth because of metabolic and compositional alterations. Cancer incidences due to toxin contamination can potentially be reduced by 50% by GDH. Better nutrition will lead to less pollution.