Transcriptome Analysis of Tobacco Leaves Under Boron Stress.

The molecular mechanism of tobacco growth inhibition induced by boron stress was not clear yet. The tobacco ' K326' at 8 leaves stage as experimental materials were cultured in Hoagland solutions with 0, 0.05, 1.00, 2.00, 3.00 mmol⋅L^-1 boron, respectively. After 4 weeks of treatment, the contents of total sugar, protein, chlorophyll, H₂O₂, boron and the antioxidant enzyme activities in tobacco leaves were detected. The transcriptome sequencing technology was used to analyze the differentially expressed genes (DEGs) and the significantly enriched metabolic pathways responding to boron stress in tobacco leaves. The results showed that, the higher the boron content, the more significant inhibition were found on the growth of tobacco plants. 2.00 mmol⋅L^-1 boron treatment significantly inhibited the growth of roots, stems, and leaves of tobacco; and significantly inhibit carbohydrate metabolism, increase H₂O₂ contents, and enhance peroxidase (POD) activity in leaves. Compared with tobacco treated with normal Hoagland solution (0.05 mmol⋅L^-1 boron), 389 DEGs that responded to 2.00 mmol⋅L^-1 boron stress specifically were enriched in sugar metabolism, lipid metabolism, hormone signaling, and plant disease resistance signaling pathways. It was found that the boron stress affected carbon and lipid metabolism in tobacco leaves, and inhibited tobacco growth by altering hormone signaling pathways. These results provided some basis for further understanding the mechanism of response to boron stress in tobacco. [ABSTRACT FROM AUTHOR]