氧胁迫对小菜蛾的影响

发布时间：2018-05-03 19:32

本文选题：青藏高原 + 小菜蛾　；参考：《福建农林大学》2017年硕士论文

【摘要】：小菜蛾是一种世界性的重要害虫,主要危害十字花科作物。十字花科蔬菜是西藏高原蔬菜的重要组成部分,占蔬菜种植面积的70%以上,对西藏地区农牧业、商品经济发展,人民生活水平改善都有重要的意义。青藏高原平均海拔超过4000米,在西藏地区空气中含氧量大约只有海平面的60%,是研究极端环境适应性的理想天然实验室。小菜蛾在进化过程中对青藏高原上极端生态环境(如低压、低氧、低温、强辐射等)具有高度适应性,是研究生物适应性进化的良好材料。由于长期生活在低氧环境中,青藏高原小菜蛾可能比平原上的小菜蛾能够更好地适应低氧环境。然而,有关这方面的研究未见任何报道。本研究通过高通量测序的分子技术与传统的两性生命表的方法相结合,揭示小菜蛾适应低氧的相关机制。1)在虫源发生地分别组建了福州品系和西藏品系小菜蛾的年龄-龄期两性生命表。通过分析这两种品系小菜蛾的生长发育历期、繁殖力、存活率等指标,以及相关的种群动态参数后发现,低氧环境对小菜蛾的发育历期有明显的影响:与西藏品系的小菜蛾相比,福州品系小菜蛾的卵、幼虫、蛹、成虫期在低氧环境下都显著缩短,特别是第一代变化明显,随着繁殖代数的增加这种差异逐渐消失;繁殖力和存活率无显著变化;福州品系小菜蛾在低氧环境下内禀增长率(r)、周限增长率(λ)、净增值率(R0)、平均世代周期(T)都显著降低。表明在低氧环境下西藏品系的小菜蛾适合度比福州品系的小菜蛾更高,对低氧的适应能力更强。2)比较常压低氧处理(1.8kPa氧分压)前后小菜蛾转录组的差异,分析相关的基因及通路,探讨小菜蛾适应低氧的分子机制。基于生物信息学的方法,获得了大量差异表达基因,并从中筛选出差异表达显著的基因。对这些差异表达基因进行功能富集分析,发现它们主要集中在脂肪酸代谢、丙酸代谢、氨基酸代谢、三羧酸循环、糖酵解或糖异生代谢、泛素水解以及新陈代谢途径等生物学过程。其中,泛素水解通路上基因的下调表达会促使缺氧诱导因子αα和β二聚体结合,从而启动与缺氧相关基因的表达,使细胞及机体适应低氧环境。除此之外,一些基因富集在与DNA复制相关的通路中,如DNA修复,核苷酸切除修复,碱基切除修复,错配修复,同源重组等;还发现与能量代谢相关的通路在小菜蛾适应低氧过程中发生了明显的变化,推测昆虫可以通过对新陈代谢过程的调节来适应不同的环境。不同品系的小菜蛾对低氧的适应机制是类似的,但是西藏品系的小菜蛾比福州品系的小菜蛾对低氧的耐受能力更强,这可能是西藏品系小菜蛾长期生活在高原缺氧的环境中自然选择的结果。
[Abstract]:Plutella xylostella is an important pest in the world, which mainly harms cruciferous crops. Cruciferous vegetables are an important part of vegetables in the Tibetan Plateau, accounting for more than 70% of the vegetable planting area, which is of great significance to the development of agriculture and animal husbandry, the development of commodity economy and the improvement of people's living standards in Tibet. The average altitude of the Qinghai-Tibet Plateau is over 4000 meters, and the oxygen content in the air in Tibet is only about 60 percent of that of the sea level. It is an ideal natural laboratory for the study of extreme environmental adaptability. Plutella xylostella has a high adaptability to extreme ecological environment (such as low pressure, low oxygen, low temperature and strong radiation) on the Qinghai-Xizang Plateau during its evolution. As a result of living in hypoxia environment for a long time, Plutella xylostella in Qinghai-Xizang Plateau may be better able to adapt to hypoxic environment than that of the diamondback moth on the plain. However, studies on this area have not been reported. In this study, high-throughput sequencing molecular technology was combined with the traditional method of amphoteric life table. To reveal the mechanism of Plutella xylostella adapting to hypoxia. 1) Age-age life tables of Plutella xylostella were established in Fuzhou strain and Xizang strain respectively. By analyzing the growth and development period, fecundity, survival rate of the two strains of Plutella xylostella, and the relative population dynamic parameters, we found that, The period of development of Plutella xylostella was obviously affected by hypoxia: compared with the Plutella xylostella in Tibet, the egg, larva, pupae and adult period of Plutella xylostella of Fuzhou strain were significantly shortened in hypoxic environment, especially the change of the first generation was obvious. With the increase of reproduction algebra, the difference gradually disappeared, the fecundity and survival rate of Plutella xylostella were not significantly changed, and the intrinsic growth rate of Plutella xylostella in Fuzhou decreased significantly under hypoxia environment, the weekly limit growth rate (位 ~ (+), net increment rate (R _ (0) and average generation cycle (T _ (T) were all significantly decreased. The results showed that the adaptability of Plutella xylostella in Xizang strain was higher than that in Fuzhou strain under hypoxic environment, and the adaptability to hypoxia was stronger. 2) the difference of transcription group of Plutella xylostella before and after hypoxia treatment (1.8kPa oxygen partial pressure). To study the molecular mechanism of Plutella xylostella adaptation to hypoxia by analyzing the related genes and pathways. A large number of differentially expressed genes were obtained based on bioinformatics, from which significant differentially expressed genes were screened. The functional enrichment analysis of these differentially expressed genes showed that they were mainly concentrated in fatty acid metabolism, propionic acid metabolism, amino acid metabolism, tricarboxylic acid cycle, glycolysis or glycometabolism. Ubiquitin hydrolysis and metabolic pathways and other biological processes. Among them, the down-regulation of gene expression in ubiquitin hydrolysis pathway will promote the binding of hypoxia inducible factor 伪伪 and 尾 dimer, thus initiate the expression of hypoxia related genes, and make cells and organism adapt to hypoxia environment. In addition, some genes are concentrated in DNA replication-related pathways, such as DNA repair, nucleotide excision repair, base excision repair, mismatch repair, homologous recombination, etc. It was also found that the pathways related to energy metabolism changed obviously in the process of Plutella xylostella adaptation to hypoxia. It was speculated that insects could adapt to different environments through the regulation of metabolic process. The adaptation mechanism of different strains of Plutella xylostella to hypoxia was similar, but the tolerance of Plutella xylostella of Tibet strain to hypoxia was stronger than that of Fuzhou strain. This may be the result of natural selection of Plutella xylostella, a Tibetan strain, living in a hypoxic environment on the plateau for a long time.
【学位授予单位】：福建农林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S433.4

【参考文献】