博士研究生陈钊为论文第一作者，王佺珍教授为论文通讯作者。
Abstract
Soil salinity and alkalinity are important factors affecting growth, development, and productivity of alfalfa (Medicago sativa), while nanomaterial could affect the growth and alleviate the stress. However, the molecular regulation mechanisms remain largely unknown about how nanoparticles treated alfalfa responds and adapts to the abiotic stress. We sequenced the transcriptomic changes in the graphene-treated leaves under salt and alkali stresses. Total 19.4 Gb of clean reads were generated by SMRT sequencing including 265,811 CCS, 219,162 FLNC readsand 12,960 non-redundant transcripts were obtained. RNA-seq analysis revealed 930, 1114 and 880 DEGs in leaf treated by graphene, graphene-salt and graphene-alkali treatment, respectively, among which hundreds genes are involved in hormonal signaling, photosynthesis, respiration, and transcriptional regulations pathways. Notably, the specific differential gene expression patterns such as antioxidant defense system and photosynthesis may rapidly confer abiotic tolerance in alfalfa leaves treated by graphene. Moreover, the physiological changes were consistent with the complex transcript profiles of the genes involved, suggesting that photosynthesis and the antioxidant defense mechanism played a critical role in reacting to salt and alkali stresses. These observations provide a full characterization of gene transcription and promote the understanding of the molecular mechanisms of nanoparticulate-treated alfalfa adaptation to abiotic stresses.
土地盐碱化是影响苜蓿生长、发育和产量的重要因素，大量研究表明纳米颗粒对植物具有积极作用，如促进种子萌发、植物生长和减缓胁迫带来的危害等。然而，施加纳米颗粒对紫花苜蓿响应非生物胁迫的分子调控机制尚不清楚。该研究测定了盐、碱胁迫下，改性纳米石墨烯处理后的紫花苜蓿叶片的全长转录组。SMRT测序共产生19.4GB的cleanreads，包括265811个环形一致性序列、219162个全长非嵌合序列和12960个非冗余转录本。二代转录组结果分析表明，石墨烯处理组、石墨烯-盐处理组和石墨烯-碱处理组叶片中分别存在930、1114和880个差异表达基因，其中数百个基因参与了植物体内的激素信号转导、光合作用、呼吸和转录调控等途径。且在非生物胁迫下，石墨烯处理后的苜蓿叶片可快速引起抗氧化防御系统和光合作用等特异性差异基因的表达，从而提升苜蓿的耐受性。此外，生理变化与相关基因转录表达谱的趋势一致，说明光合作用和抗氧化防御机制在盐、碱胁迫反应中起着关键作用。这些结果提供了一个完整的基因转录特征，可促进对纳米颗粒提升苜蓿适应非生物胁迫分子机制的认识。
