RNA-Seq, physiological, and biochemical analysis of burley tobacco response to nitrogen deficiency

Yafei Li,Dong Chang,Huijuan Yang,Hongzhi Shi,Xiang Zhang

doi:10.1038/s41598-021-93363-w

Abstract

To explore the effects of nitrogen deficiency in burley tobacco, two varieties were cultivated and subjected to conditions of sufficient and deficient nitrogen. The natural characteristics of varieties TN90 and TN86 during tobacco cultivation were similar for nitrogen metabolism. Both carbon and nitrogen metabolism were significantly affected by reducing amounts of applied nitrogen. Under nitrogen-deficient conditions, average leaf biomass, root weight, photosynthetic rate (Pn), pigment levels, total nitrogen, and nitrate content of TN86 and TN90 were significantly decreased by 52.88%, 69.19%, 22.65%, 46.80%, 37.42%, and 79.15%, respectively (p < 0.01). Nicotine and soluble reducing sugar contents were significantly decreased by 96.67% and 95.12%, respectively, in TN86 roots (p < 0.01), which was consistent with the reductions in root surf area, average diameter, and root volume. Nitrogen deficiency induced 6318 differentially expressed genes in both TN90 and TN86, which were highly expressed. In total, 428 upregulated genes were analysed and found to be mainly enriched in the MAPK signalling pathway, sesquiterpenoid and triterpenoid biosynthesis, and arginine and proline metabolism. Meanwhile, 213 downregulated genes were analysed and found to be mainly enriched in photosynthesis, nitrogen metabolism, and amino acid biosynthesis. Reduced pigment content and Pn may result in low carbohydrate formation and decreased leaf biomass in burley tobacco under nitrogen-deficient conditions.

Highlights

To explore the effects of nitrogen deficiency in burley tobacco, two varieties were cultivated and subjected to conditions of sufficient and deficient nitrogen
The results indicated that genes in burley tobacco involved in photosynthesis were suppressed under conditions of reduced nitrogen application, which was consistent with the decreased accumulation of leaf biomass
The leaf biomass of burley tobacco plants was significantly decreased by nitrogen deficiency (p < 0.01)

Summary

Introduction

To explore the effects of nitrogen deficiency in burley tobacco, two varieties were cultivated and subjected to conditions of sufficient and deficient nitrogen. Under nitrogen-deficient conditions, average leaf biomass, root weight, photosynthetic rate (Pn), pigment levels, total nitrogen, and nitrate content of TN86 and TN90 were significantly decreased by 52.88%, 69.19%, 22.65%, 46.80%, 37.42%, and 79.15%, respectively (p < 0.01). Reduced pigment content and Pn may result in low carbohydrate formation and decreased leaf biomass in burley tobacco under nitrogen-deficient conditions. Overuse of nitrogen fertiliser in tobacco cultivation may lead to environmental problems as a result of leaching and can increase nitrate accumulation in the plant tissues[10], which negatively affects the quality of burley tobacco[3]. Burley tobacco varieties TN86 and TN90 are the most commonly cultivated tobacco cultivars in China, and their characteristics regarding nitrogen fertiliser application, yield, and value are similar 12, but their responses to conditions of nitrogen deficiency at the transcriptome level are unclear. There are currently few reports on the effects of nitrogen deficiency in burley tobacco at the transcriptome level (Supplementary Information 1)

Methods

Results

Conclusion