Shi Rui, Allen Zachary, Steede Tyler, Lewis Ramsey S
Department of Crop and Soil Sciences, N.C. State University, Campus Box 7620, Raleigh, NC, 27695, USA.
BMC Genomics. 2025 Jun 6;26(1):566. doi: 10.1186/s12864-025-11764-x.
Tobacco with modified genetics controlling alkaloid accumulation has been of interest because of the possibility of mandated lowering of nicotine levels in combustible cigarettes by regulatory authorities. Transcription factors coded by the , , and loci act as positive regulators of genes directly involved in alkaloid accumulation. In this research, different combinations of alternative alleles at these loci were assembled in homozygous nearly isogenic lines (NILs). Recessive / alleles were found to have greater influence on alkaloid reduction as compared to a mutant allele. When combined into single genotypes, these alleles operated in an additive manner to further reduce alkaloid levels in field and greenhouse experiments. This was at the expense of reduced cured leaf quality, however. An RNA-seq experiment was carried out to investigate global changes in root expression due to different genotypes at these three loci. Up to 1,028 differentially expressed genes (DEGs) were identified between the studied NILs, with expression of most DEGs being downregulated by recessive alleles. In general, the mutant allele appeared to suppress a subset of previously characterized alkaloid biosynthetic genes with relatively weaker effect as compared to the / alleles. There was little evidence that root expression of or genes was affected by allelic variability at the locus, or vice versa. The list of DEGs influenced by genotypes at these three loci may contain candidate genes coding for currently uncharacterized enzymes involved with tobacco alkaloid accumulation.
The online version contains supplementary material available at 10.1186/s12864-025-11764-x.
由于监管机构可能强制降低可燃香烟中的尼古丁含量，具有控制生物碱积累的改良基因的烟草一直备受关注。由、和基因座编码的转录因子作为直接参与生物碱积累的基因的正向调节因子。在本研究中，这些基因座上替代等位基因的不同组合被组装到纯合近等基因系（NILs）中。与突变等位基因相比，隐性/等位基因对生物碱减少的影响更大。当组合成单一基因型时，这些等位基因以加性方式起作用，在田间和温室试验中进一步降低生物碱水平。然而，这是以降低烤后烟叶质量为代价的。进行了一项RNA测序实验，以研究由于这三个基因座的不同基因型导致的根部表达的全局变化。在研究的NILs之间鉴定出多达1028个差异表达基因（DEG），大多数DEG的表达被隐性等位基因下调。一般来说，与/等位基因相比，突变等位基因似乎抑制了一部分先前表征的生物碱生物合成基因，但其作用相对较弱。几乎没有证据表明或基因的根部表达受基因座上等位基因变异的影响，反之亦然。受这三个基因座基因型影响的DEG列表可能包含编码目前未表征的参与烟草生物碱积累的酶的候选基因。
在线版本包含可在10.1186/s12864-025-11764-x获取的补充材料。
