野生与驯化油料作物尼日尔（Guizotia abyssinica）叶绿体RNA编辑的比较分析揭示驯化驱动的适应性分化与野生种的特异性抗逆机制

本研究首次系统比较了尼日尔（Guizotia abyssinica）野生型与三个地理来源驯化基因型的叶绿体RNA编辑差异，揭示野生种G. scabra（GS）具有最丰富的RNA编辑位点（404个C→U转换），显著高于驯化种（166–304个）。研究通过RNA-seq与REDItools鉴定编辑热点（如ndhF、rpoC1、petD），结合PPR、MORF、ORRM等编辑因子（editosome）的表达与系统进化分析，表明驯化过程导致编辑多样性减少，而野生种通过维持高效RNA编辑机制（尤其非 synonymous 编辑）增强抗逆性。该工作为尼日尔抗逆育种提供了关键分子靶点与理论依据。

　　

Highlight

RNA editing in organellar genomes is increasingly recognized as a vital regulatory mechanism in plant stress responses, development, and adaptation (Fujii and Small, 2011). Here, we characterized RNA editing events in the chloroplast genome of G. abyssinica (niger), an economically important but underutilized oilseed crop with underexplored genetic and genomic resources. By analyzing four transcriptomes representing geographically and genetically distinct accessions ? JNS-28 (India), ETH-19

植物细胞器基因组中的RNA编辑日益被认为是调控植物应激响应、发育与适应的关键机制（Fujii and Small, 2011）。本研究首次对经济重要但未被充分开发的油料作物——尼日尔（G. abyssinica）的叶绿体RNA编辑事件进行了系统解析。通过分析四个代表不同地理与遗传背景的材料——印度的JNS-28、埃塞俄比亚的ETH-19、美国的USDA-15以及野生种G. scabra（GS）——我们揭示了基因型间显著的编辑差异。野生型GS展现出最丰富的编辑事件，暗示其在适应逆境中扮演关键角色。这些发现为理解尼日尔在驯化过程中RNA编辑的演化及其与抗逆性的分子关联提供了新视角。

Discussion

RNA editing in organellar genomes is increasingly recognized as a vital regulatory mechanism in plant stress responses, development, and adaptation (Fujii and Small, 2011). Here, we characterized RNA editing events in the chloroplast genome of G. abyssinica (niger), an economically important but underutilized oilseed crop with underexplored genetic and genomic resources. By analyzing four transcriptomes representing geographically and genetically distinct accessions ? JNS-28 (India), ETH-19 (Ethiopia), USDA-15 (USA), and the wild relative G. scabra (GS) ? we uncovered substantial inter-genotypic variation. The wild genotype GS exhibited the highest number of editing events, suggesting its role as a genetic reservoir for adaptive traits. These findings provide new insights into the evolution of RNA editing during domestication and its molecular links to stress resilience in niger.

Conclusion

The present study provides the first comprehensive chloroplast RNA editing analysis in Guizotia abyssinica and its wild relative G. scabra, uncovering substantial inter-genotypic variation. The wild genotype exhibited the highest number of editing events, highlighting its potential as a genetic reservoir for adaptive traits. Predominantly characterized by C-to-U transitions, the editing landscape was concentrated in protein-coding genes such as ndhF, rpoC1, and petD, underscoring the functional importance of these modifications in photosynthesis and stress adaptation. Furthermore, the identification and differential expression analysis of PPR, MORF, and OZ1 family members across genotypes revealed domestication-driven divergence, with wild-specific upregulation of several editing factors. These results not only elucidate the organellar transcriptomic plasticity in niger but also establish a molecular framework linking RNA editing to environmental resilience. This work highlights novel targets for breeding and biotechnological improvement of this underutilized oilseed crop, offering strategies to enhance stress tolerance and productivity through manipulation of RNA editing machinery.

本研究首次对Guizotia abyssinica及其野生近缘种G. scabra开展了全面的叶绿体RNA编辑分析，揭示了显著的基因型间变异。野生型展现出最丰富的编辑事件，突显其作为适应性性状遗传库的潜力。编辑景观以C→U转换为主导，并集中于ndhF、rpoC1和petD等蛋白编码基因，强调了这些修饰在光合作用与逆境适应中的功能重要性。此外，对不同基因型中PPR、MORF和OZ1家族成员的鉴定与差异表达分析揭示了驯化驱动的分化，野生型中多个编辑因子特异性上调。这些结果不仅阐明了尼日尔细胞器转录组的可塑性，更为RNA编辑与环境抗逆性之间建立了分子框架。该研究为这一未被充分利用的油料作物的育种与生物技术改良提供了新靶点，提出了通过操纵RNA编辑机制以增强抗逆性和生产力的新策略。