Nitrogen and photorespiration pathways, salt stress genotypic tolerance effects in tomato plants (Solanum lycopersicum L.)

Nitrogen is necessary to synthesize compounds such as chlorophyll, amino acids, nucleic acids, proteins, lipids, and other nitrogen (N) metabolites. In this sense, saline stress produces a decrement in the quality and quantity of crop production around the world due to an osmotic and ionic imbalance that alters the N metabolism. The objective of this work is to verify if the genotypic variability and a better nitrogen metabolism regulation improve tolerance to saline stress in tomato plants. This study was conducted with (Grand Brix and Marmande RAF) two tomato commercial genotypes (Solanum lycopersicum L). N forms, N metabolism, N use efficiency (NUE) parameters and amino acid profile were analyzed. A greater GS/GOGAT cycle enzyme activity could promote a better N integration in the plant, besides it promotes the generation of osmoprotective amino acids such as proline and improves the salt stress tolerance. A more effective N metabolism regulation indicates more salt tolerance. Our results showed a better effective N metabolism regulation by Grand Brix.