Ntlht1 Mutation Enhances Low Nitrogen Tolerance

The results indicate that the NtLHT1 mutation enhances LN tolerance in tobacco. The contents of nitrate nitrogen and ammonium nitrogen, as well as the activities of nitrate reductase and glutamine synthetase, were greater in the mutants than in the wild type (WT). Moreover, the contents of some amino acids changed in the mutant. Transcriptome sequencing of roots under LN treatment revealed that the Ntlht1mutant presented 726 differentially expressed genes (DEGs). These DEGs were involved mainly in phenylpropanoid biosynthesis, starch and sucrose metabolism, and cysteine and methionine metabolism. The tobacco NtLHT1 mutant was hydroponically cultured in LN solution for 15 days. Then the roots from each material were collected, they were immediately stored in liquid nitrogen. After total RNA was extracted from the roots, the residual DNA was digested with DNase, and the mRNA was enriched to finish the library. Sequencing was performed after the library was constructed. The DESeq2 software package was used to screen for DEGs.