水稻秧苗期低温胁迫响应机制研究 -农学专业

摘要

水稻作为全球重要的粮食作物，其生长发育易受低温胁迫影响，尤其在秧苗期对低温更为敏感。本研究旨在揭示水稻秧苗期响应低温胁迫的分子机制，为培育耐寒水稻品种提供理论依据。通过转录组测序、代谢组分析和生理指标测定等多组学技术，系统研究了低温胁迫下水稻秧苗的基因表达谱、代谢物变化及生理响应特征。结果表明，低温胁迫显著诱导了水稻秧苗中与抗寒相关的基因表达，包括CBF/DREB转录因子家族、LEA蛋白基因以及抗氧化酶基因等；同时检测到多种渗透调节物质和抗氧化物质的积累，如脯氨酸、可溶性糖和谷胱甘肽等。进一步分析发现，低温胁迫激活了ABA信号通路和MAPK级联反应，并通过调控下游靶基因的表达来增强植株的抗寒能力。此外，本研究首次揭示了microRNA在低温胁迫响应中的调控作用，发现miR319和miR393等通过靶向生长相关基因参与抗寒调控网络。基于上述结果，构建了水稻秧苗期低温胁迫响应的分子调控模型，阐明了关键基因和代谢途径的协同作用机制。

关键词：水稻秧苗期；低温胁迫；分子机制；多组学分析

STUDY ON RESPONSE MECHANISM OF LOW TEMPERATURE STRESS IN RICE SEEDLING STAGE

ABSTRACT

As an important food crop in the world, rice is susceptible to low temperature stress, especially in the seedling stage. The aim of this study was to reveal the molecular mechanism of rice seedling response to low temperature stress, and to provide theoretical basis for breeding cold-resistant rice varieties. The gene ex pression profile, me tabolite changes and physiological response characteristics of rice seedlings under low temperature stress were systematically studied by transc riptome sequencing, me tabolome analysis and physiological index determination. The results showed that low temperature stress significantly induced the ex pression of genes related to cold resistance in rice seedlings, including CBF/DREB transc ription factor family, LEA protein gene and antioxidant enzyme gene. Accumulation of various osmoregulatory substances and antioxidants, such as proline, soluble sugar and glutathione, were also detected. Further analysis showed that low temperature stress activated ABA signaling pathway and MAPK cascade reaction, and enhanced the cold resistance of plants by regulating the ex pression of downstream target genes. In addition, this study revealed for the first time the regulatory role of microRNA in response to low temperature stress, and found that miR319 and miR393 participate in the cold resistance regulatory network by targeting growth-related genes. Based on the above results, a molecular regulatory model of rice seedling response to low temperature stress was constructed, and the synergistic mechanism of key genes and me tabolic pathways was elucidated.

KEY WORDS：Rice seedling stage; Low temperature stress; Molecular mechanism; Multi-omics analysis

摘要 I

ABSTRACT II

第1章绪论 2

1.1 研究背景及意义 2

1.2 水稻秧苗期低温胁迫响应机制研究现状 2

第2章水稻秧苗期低温胁迫的生理响应机制 4

2.1 低温对水稻秧苗光合作用的影响 4

2.2 低温胁迫下水稻秧苗的抗氧化系统变化 4

2.3 水稻秧苗在低温条件下的渗透调节机制 4

第3章水稻秧苗期低温胁迫的分子调控网络 6

3.1 低温响应关键基因的表达分析 6