Main conclusionArundo donax ecotypes react differently to salinity, partly due to differences in constitutive defences and methylome plasticity.AbstractArundo donax L. is a C3 fast-growing grass that yields high biomass under stress. To elucidate its ability to produce biomass under high salinity, we investigated short/long-term NaCl responses of three ecotypes through transcriptional, metabolic and DNA methylation profiling of leaves and roots. Prolonged salt treatment discriminated the sensitive ecotype ‘Cercola’ from the tolerant ‘Domitiana’ and ‘Canneto’ in terms of biomass. Transcriptional and metabolic responses to NaCl differed between the ecotypes. In roots, constitutive expression of ion transporter and stress-related transcription factors’ genes was higher in ‘Canneto’ and ‘Domitiana’ than ‘Cercola’ and 21-day NaCl drove strong up-regulation in all ecotypes. In leaves, unstressed ‘Domitiana’ confirmed higher expression of the above genes, whose transcription was repressed in ‘Domitiana’ but induced in ‘Cercola’ following NaCl treatment. In all ecotypes, salinity increased proline, ABA and leaf antioxidants, paralleled by up-regulation of antioxidant genes in ‘Canneto’ and ‘Cercola’ but not in ‘Domitiana’, which tolerated a higher level of oxidative damage. Changes in DNA methylation patterns highlighted a marked capacity of the tolerant ‘Domitiana’ ecotype to adjust DNA methylation to salt stress. The reduced salt sensitivity of ‘Domitiana’ and, to a lesser extent, ‘Canneto’ appears to rely on a complex set of constitutively activated defences, possibly due to the environmental conditions of the site of origin, and on higher plasticity of the methylome. Our findings provide insights into the mechanisms of adaptability of A. donax ecotypes to salinity, offering new perspectives for the improvement of this species for cultivation in limiting environments.

中文翻译：

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转录、代谢和 DNA 甲基化变化支持 Arundo donax 生态型对 NaCl 过量的反应

主要结论 Arundo donax 生态型对盐度的反应不同，部分原因是组成防御和甲基化组可塑性的差异。摘要 Arundo donax L. 是一种 C3 速生草，在压力下产生高生物量。为了阐明其在高盐度下产生生物量的能力，我们通过叶和根的转录、代谢和 DNA 甲基化分析研究了三种生态型的短期/长期 NaCl 反应。长时间的盐处理在生物量方面将敏感的生态型“Cercola”与耐受的“Domitiana”和“Canneto”区分开来。不同生态型对 NaCl 的转录和代谢反应不同。在根上，'Canneto' 和'Domitiana' 中离子转运蛋白和应激相关转录因子基因的组成型表达高于'Cercola' 和21 天NaCl 驱动了所有生态型的强烈上调。在叶子中，未受胁迫的'Domitiana'证实了上述基因的更高表达，其转录在'Domitiana'中被抑制，但在NaCl处理后在'Cercola'中被诱导。在所有生态型中，盐度增加了脯氨酸、ABA 和叶片抗氧化剂，同时在“Canneto”和“Cercola”中上调抗氧化基因，但在“Domitiana”中没有，后者耐受更高水平的氧化损伤。DNA 甲基化模式的变化突出了耐受性“Domitiana”生态型将 DNA 甲基化调整为盐胁迫的显着能力。'Domitiana' 的盐敏感性降低，并且在较小程度上，'Canneto' 似乎依赖于一组复杂的组成型激活防御，这可能是由于起源地点的环境条件，以及甲基化组的更高可塑性。我们的研究结果为 A. donax 生态型对盐度的适应性机制提供了见解，为改善该物种在有限环境中的栽培提供了新的视角。