七星瓢虫滞育的代谢适应及脂代谢的转录组学机理研究

发布时间：2018-06-15 20:53

本文选题：七星瓢虫 + 滞育　；参考：《中国农业科学院》2016年硕士论文

【摘要】：随着农作物病虫害绿色防控技术与应用的发展,生物防治的重要性与日俱增。七星瓢虫Coccinella septempunctata L.是优良的天敌昆虫,可捕食蚜、蚧等多种农林害虫,在多个国家已商品化生产应用。滞育是多数天敌昆虫具有的遗传属性,调控天敌昆虫滞育可以延长天敌产品的货架期、保证长距离运输、提高抗逆性,促进天敌昆虫产品的贮存、运输和大规模应用。对七星瓢虫滞育的研究涵盖了解剖学特征、诱导技术、滞育后生物学、滞育机理等各方面,促进了对七星瓢虫滞育科学规律的深入了解,对指导生产实践应用具有重要意义。滞育期间营养物质的贮存和利用对昆虫顺利度过滞育期具有重要的意义。本研究以滞育七星瓢虫解剖学为基础,系统地研究了包括含水量、脂质、碳水化合物、蛋白质等在内的生化物质含量波动情况;归纳总结了正常发育、滞育和滞育解除三种不同发育状态下的七星瓢虫过冷却点变化特征;测试分析了正常发育、滞育和滞育解除个体转录组测序结果,获得大量的滞育差异表达基因;研究筛选出与脂质代谢相关基因并深入分析,为探究瓢虫滞育营养物质利用和调控提供参考。主要研究结果如下:1.明确了七星瓢虫在正常发育、滞育和滞育解除阶段体内含水量、脂质、碳水化合物、蛋白质等重要生化代谢物含量有显著差异:滞育个体含水量、总蛋白含量显著低于正常发育和滞育解除个体,说明滞育瓢虫体内代谢活动降低;滞育个体的脂质(173.66±19.01μg/mg)比正常发育(80.04±15.82μg/mg)、滞育解除(83.83±12.54μg/mg)个体增加近1倍,总糖和糖原含量可高出2倍和7倍,是滞育瓢虫重要的营养物质来源;而甘油、山梨醇、海藻糖含量在三种不同发育阶段的瓢虫中差异不显著。此外,滞育瓢虫糖原大量积累,与正常发育和滞育解除的个体存显著性差异;而滞育瓢虫的海藻糖含量与正常发育和滞育解除个体之间无显著差异,证实了七星瓢虫的滞育属糖原积累类型。2.证实了七星瓢虫在滞育阶段耐寒性提高:滞育七星瓢虫过冷却点为-16.53℃,低于正常发育个体(-14.07℃)和滞育解除个体(-15.29℃),且滞育驯化后七星瓢虫的耐寒性有所提高。3.应用转录组技术检测正常发育-滞育-滞育解除瓢虫基因转录情况,经过剪接、过滤、拼接等步骤,共获得82,820个Unigenes,滞育-正常发育差异表达基因3,501个,其中滞育上调2,125个、下调1,376个;滞育解除-滞育差异表达基因1,427个,其中滞育上调749个、下调表达678个。差异基因在分子功能类别和脂肪酸代谢通路、药物代谢、碳代谢等通路得到富集。4.将滞育-滞育解除差异基因和滞育解除-滞育差异基因两两比较,并藉助KEGG数据库,共筛选出滞育期间与脂质合成相关的差异基因17个,在滞育期间呈现出不同程度的上调表达,涉及了脂肪酸合成、β-氧化、脂质转运等代谢途径,除脂肪酸合酶、脂链延伸酶、脂肪酸去饱和酶基因、脂质转运蛋白等与脂质合成相关酶类上调表达外,同时一部分与脂质分解相关的酶,如酯酶、酰基转移酶等同样上调表达,可能与提高滞育瓢虫免疫力有关;此外,与激素合成相关基因表达上调,可能对滞育瓢虫卵巢发育受抑相关。
[Abstract]:With the development of green prevention and control technology and application of crop pests and diseases, the importance of biological control is increasing. Coccinella septempunctata L. of Seven Star ladybug is a good natural enemy insect. It can catch aphids, scale insects and other agroforestry pests, and has been commercialized in many countries. Diapause is the genetic attribute of most natural enemy insects. Diapause of enemy insects can prolong the shelf life of natural enemy products, ensure long distance transportation, improve the resistance and promote the storage, transportation and large-scale application of natural enemy insect products. The study of diapause of Seven Star Ladybug covers anatomic characteristics, induction technique, biologic after diapause, and hysteretic mechanism, which promotes the diapause science of seven ladybug. The deep understanding of the law is of great significance for guiding the application of production practice. The storage and utilization of nutrients during diapause is of great significance for the insect to pass through the diapause period. Based on the diapause anatomy of the ladybug, this study systematically studies the biochemical substances, including water content, fat, carbohydrate, protein and so on. The characteristics of the changes in the subcooling point of the normal development, diapause and diapause in three different developmental states were summarized, and the results of normal development, diapause and diapause were analyzed, and a large number of diapause differential tables were obtained, and the genes related to lipid metabolism were screened. The main research results are as follows: 1. the water content in the normal development, diapause and diapause release stage of the ladybug is clear. The content of the important biochemical metabolites, such as lipid, carbohydrate, protein, and other important biochemical metabolites in the stage of normal development, diapause and diapause are clearly different: the water content and total protein content of diapause individual The metabolic activity of diapause Ladybug was lower than normal development and diapause, and the lipid (173.66 + 19.01 g/mg) of diapause individual was more than normal (80.04 + 15.82 mu g/mg), and the diapause (83.83 + 12.54 g/mg) individual increased nearly 1 times, the total sugar and glycogen content could be higher than 2 times and 7 times, and it was an important nutrient of diapause ladybug. The contents of glycerol, sorbitol and trehalose were not significantly different among the ladybug of three different developmental stages. In addition, the accumulation of glycogen in diapause Ladybug was significantly different from those of normal development and diapause, while the trehalose content of diapause Ladybug was not significantly different from that of normal development and diapause. The accumulation type.2. of the diapause of Ladybug confirmed that the cold tolerance of the ladybug was improved at the diapause stage: the cross cooling point of diapause was -16.53 C, lower than the normal developing individuals (-14.07 C) and diapause individual (-15.29 C), and the cold tolerance of the ladybug was improved after the diapause and domestication, and the.3. application transcriptional group technique was used to detect normal development. Diapause - diapause relieved the gene transcription of ladybug. Through the steps of splicing, filtering and splicing, there were 82820 Unigenes, diapause and normal development differentially expressed genes, including 2125 diapause, 1376 down regulation and 1427 diapause diapause differentially expressed genes, including 749 diapause and 678 down regulated genes. In the molecular functional category and fatty acid metabolism pathway, drug metabolism, carbon metabolism and other pathways,.4. was enriched to compare diapause diapause release differential genes and diapause diapause differential genes 22, and 17 differential genes related to lipid synthesis during diapause were screened by KEGG database, and different degrees were presented during diapause. The up-regulated expression involves fatty acid synthesis, beta oxidation, lipid transport and other metabolic pathways. Besides fatty acid synthase, fat chain elongation enzyme, fatty acid desaturase gene, lipid transporter protein and lipid synthesis related enzymes up regulation, some enzymes, such as esterase and acyl transferase, are also up-regulated, which are related to lipid decomposition. It may be related to the enhancement of the immunity of diapause ladybug. In addition, the up regulation of genes related to hormone synthesis may be related to the inhibition of ovarian development in diapause ladybirds.
【学位授予单位】：中国农业科学院
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S476.2

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