【摘要】 为多维度分析中能质子束辐射在改善水稻耐盐碱性中的应用前景，本研究筛选了水稻耐盐碱突变体，在表型、生理生化和基因组水平研究了中能质子束辐射对水稻耐盐碱性的影响。结果表明，质子辐射对种子活力的影响大于微重力，低剂量（≤10 Gy）的质子辐射促进种子萌发，高剂量（≥100 Gy）抑制种子萌发。叶绿素含量分析结果表明，10 Gy质子束辐射可提高盐碱胁迫下水稻突变体的叶绿素含量，增强苗期光合作用；生理生化结果显示，突变体的超氧化物歧化酶（SOD）和过氧化氢酶（CAT）活性均显著高于野生型（WT），丙二醛（MDA）含量显著下降，呈现出更强的抗氧化能力；全基因组重测序（WGS）分析结果表明，质子束诱导的单碱基替换（SBSs）和插入/缺失（InDels）共有53.5%发生在基因组的基因间区。SBS是数量最多的突变，占所有变异的80.4%。单碱基转换是SBSs的主要形式，平均转换和颠换比为3.0，其中一半以上的InDels为短片段突变（1～2 bp）。KEGG通路富集分析结果表明，水稻可能主要通过次生代谢物的生物合成、植物激素信号转导、苯丙烷生物合成和谷胱甘肽代谢途径来抵御盐碱胁迫。本研究可为中能质子辐射在水稻耐盐碱性改良中的应用提供理论指导，并丰富对质子束辐射诱变机制的理解。更多还原

【Abstract】 To explore the potential application of medium-energy proton beam irradiation to enhance salinityalkalinity tolerance in rice, the impacts of medium-energy proton beam irradiation on salinity tolerance in rice were investigated at phenotypic, physiological, biochemical, and genomic levels and salinity tolerant mutants were screened. Results showed that proton irradiation had a greater impact on seed viability than microgravity. Specifically, low doses （≤10 Gy） of proton irradiation promoted seed germination, whereas high doses （≥100 Gy） inhibited it. Rice mutant obtained with 10 Gy proton beam irradiation exhibited increased chlorophyll content and concomitant enhancement in seedling photosynthesis when subjected to salinity stress. Compared to the wild-type(WT), the mutant exhibited significantly higher superoxide dismutase(SOD) and catalase(CAT) activities along with significantly reduced malondialdehyde(MDA) content, indicating enhanced antioxidant capacity. Whole-genome sequencing(WGS) analysis demonstrated that 53. 5% of proton beam-induced single-base substitutions(SBSs) and insertions/deletions(InDels) occurred in intergenic regions. SBSs were the most abundant variant type, accounting for 80. 4% of all mutations. Single-base transitions constituted the predominant type among all observed SBSs, with an average transition/transversion ratio of 3. 0. Over half of the InDels were short-fragment mutations(1-2 bp). KEGG pathway enrichment analysis suggested that rice may counteracts salinity-alkalinity stress primarily through secondary metabolites biosynthesis, plant hormone signal transduction, phenylpropanoid biosynthesis, and glutathione metabolism. This study provides theoretical guidance for employing medium-energy proton irradiation to improve salinity tolerance in rice and for elucidating the underlying mutagenic mechanisms.更多还原