硼胁迫下烟草叶片转录组分析

Transcriptome Analysis of Tobacco Leaves Under Boron Stress

为揭示硼胁迫抑制烟叶生长的分子机理,以8叶期栽培烟草‘K326’为实验材料,分别用含硼量为0、0.05、1.00、2.00、3.00 mmol·L^(-1)的Hoagland培养液浇灌处理4周,而后检测烟叶中的总糖、蛋白质、叶绿素、H2O2、硼含量及抗氧化酶活性等,并通过转录组测序技术分析硼胁迫下烟叶差异表达基因及显著富集的代谢通路。结果显示,硼含量越高,对烟株的生长抑制越显著。2.00 mmol·L^(-1)的硼处理即可显著抑制烟草根、茎和叶生长;并显著抑制叶片中糖类物质代谢,增加H2O2含量及增强氧化物酶(POD)活性。与常规Hoagland培养液(含硼量0.05 mmol·L^(-1))浇灌的烟草相比,仅响应2.00 mmol·L^(-1)硼胁迫的389个差异表达基因富集于糖代谢、脂类代谢、激素信号及植物抗病信号途径。说明高浓度硼胁迫可能影响烟叶中的碳代谢和脂类代谢,并可能通过改变激素信号途径抑制烟草生长。从而为深入理解烟草对硼胁迫的响应机制提供更多依据。

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.