KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 白桦响应盐胁迫的生理学机制及相关基因的鉴定 | |
| 美合日古丽·米吉提 | |
| Subtype | 硕士 |
| Thesis Advisor | 王玉成 |
| 2017-05-01 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 新疆乌鲁木齐 |
| Degree Discipline | 工程硕士 |
| Keyword | 白桦 生理学响应 LEA 基因 盐胁迫 qRT-PCR Betula platyhylla Suk physiological responses LEA gene salt stress qRT-PCR |
| Abstract | Birches belong to the genus Betula in the family Betulaceae. Birch trees arefast-growing woody plants that adapt to adverse environments, and are widely distributedfrom north Europe to Russia, north of China, and Japan. Therefore, it is important tostudy the mechanism of salt stress tolerance in birch plants. Recently, the sequencingwhole-genome of Betula platyphylla Suk. has been completed. Therefore, it has laid asolid foundation for studying the Betula platyphylla Suk’s genetic resources. Here, we treated birch seedlings with a solution of 100 mM NaCl and studied thephysiological and related molecular response of white birch (Betula Platyphylla Suk.) tosalt stress. We found that abscisic acid and Ca2+level were induced in birch during theearly salt stress period, ABA was induced during early salt stress period, and thendecreased, and Ca2+level increased slowly but maintained at a high level for a long time. Under salt conditions, photosynthetic activity was inhibited; the Salt-Overly-Sensitive(SOS) pathway was activated in birch roots; reactive oxygen species (ROS) wasaccumulated, and superoxide dismutase is the main ROS scavenger in roots, whileperoxidase is the main ROS scavenger in leaves. Proline plays a role in stress tolerance inboth roots and leaves; however, soluble sugars and trehalose also have roles in salt stresstolerance, mainly in leaves. Additionally, the genes that might have essential roles incontrolling some of these physiological changes were identified. In leaves, the POD5 andPOD8 genes might play a main role in increase the POD activity. In roots, the SOD1 andSOD4 genes might make main contributions to the increased SOD activity during saltstress. P5CS1 is closely related to the biosynthesis of proline in roots, and P5CS2 mightplay a main role in proline biosynthesis in leaves; the TPS4 and TPP3 genes might playimportant roles in the biosynthesis of trehalose in birch during salt stress period. Therefore, they represent good candidate genes to characterize the salt tolerancemechanism of birch and to breed stress tolerant plants. Late Embryogenesis Abundant (LEA) proteins are accumulated during the last period of seed development, and also play important roles in abiotic stress tolerance of plants. Inthe present study, we studied the 13 LEA genes that are highly similar with the stresstolerance LEA genes in Arabidopsis, and they were cloned from B. platyphylla. Inaddition, the LEA genes that are in response to salt stress were further identified usingqRT-PCR. These LEA genes involving in salt stress response will be the good candidategenes in genetic approaches for breeding salt stress tolerance in plants. |
| Other Abstract | 白桦为桦木科桦属植物，具有生长迅速，对环境适应能力强等特点，广泛分布于北欧、俄罗斯至我国东北及日本的广大地区，具有耐贫瘠和抗逆能力强等特点。因此，对其进行抗逆调控机制的研究具有重要意义。目前，白桦基因组已经测序完成，为本研究奠定了坚实的基础。本研究用 100 mM 的 NaCl 胁迫白桦（Betula platyphylla Suk）幼苗，研究其响应盐胁迫的生理机制，并进一步研究了与这些生理机制相关的分子生物学机制。盐胁迫初期，白桦中的信号分子 ABA 和 Ca2+含量被诱导增加，ABA 在胁迫初期增加后迅速恢复到胁迫前水平，而 Ca2+则长期保持较高水平。持续的盐胁迫导致白桦光合作用被抑制，白桦根部的 SOS 信号传导途径被激活；活性氧（ROS）含量持续积累，而白桦也相应地启动了抗氧化机制。比较 SOD 与 POD 酶活性发现，盐胁迫下，白桦根部主要是 SOD 酶起作用，而白桦叶片主要是 POD 酶起作用。盐胁迫下，脯氨酸在白桦叶片和根中都会持续积累，而可溶性糖和海藻糖主要在白桦叶片中显著积累。同时，本论文研究了以上生理调控途径中的相关基因的表达，鉴定了在这些抗逆生理学途径中起关键作用的基因。其中，POD 酶合成相关基因 POD5 和 POD8可能在盐胁迫下提高叶片 POD 活性中起主要作用；SOD 合成相关基因 SOD1 和SOD4 可能在盐胁迫时诱导根 SOD 活性中起主要作用。白桦受盐胁迫时，P5CS1 基因可能主要在叶片中的脯氨酸合成中起作用，而 P5CS2 基因主要在根中的脯氨酸合成中起作用。海藻糖合成相关基因中 TPS4 和 TPP3 可能主要在叶片中海藻糖的合成中起作用。这些基因可以作为研究白桦响应盐胁迫机制的目的基因，也是用于抗逆分子育种的理想候选基因。LEA 蛋白（Late Embryogenesis Abundant proteins）是一类植物胚胎发育晚期种子中大量富集的蛋白，在植物抗逆过程中起重要作用。本研究根据已报导的拟南芥胁迫相关 LEA 基因，从白桦数据库中鉴定出 13 个同源的白桦 LEA 基因。通过生物信息学以及 qRT-PCR 方法研究其生物学特性和盐胁迫后的表达模式，从而找出在可能参与白桦响应盐胁迫过程的 LEA 基因，这些 LEA 基因可作为植物抗逆分子育种的候选基因。 |
| Subject Area | 生物工程 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/14892 |
| Collection | 研究系统_荒漠环境研究室 |
| Affiliation | 中国科学院新疆生态与地理研究所 |
| First Author Affilication | 中国科学院新疆生态与地理研究所 |
| Recommended Citation GB/T 7714 | 美合日古丽·米吉提. 白桦响应盐胁迫的生理学机制及相关基因的鉴定[D]. 新疆乌鲁木齐. 中国科学院大学,2017. |
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