体内细菌对松材线虫侵染松树后基因转录表达的影响毕业论文

 2021-04-20 09:04

摘 要

许多研究表明松材线虫的伴生细菌在松材线虫病中起着重要作用。与线虫体表细菌相比,其体内细菌受外界环境影响小,与松材线虫的联系更密切。因此,进一步研究松材线虫体内细菌在松材线虫与松树互作中的作用,探究内在的分子机理显得十分重要。本研究在前期已将无菌松材线虫和带菌松材线虫与松树互作的基础上,对得到的转录组数据进行分析和验证,从转录组水平较全面地揭示细菌在松材线虫与松树互作中对松材线虫基因的调控作用。初步研究结果如下:

1. 与松树互作后,嗜麦芽窄食单胞菌NSPmBx03处理的松材线虫与无菌松材线虫相比,差异表达基因有4240个,其中1477个为上调表达,2763个为下调表达。结果表明嗜麦芽窄食单胞菌对松材线虫的基因表达具有影响。

2. 通过对松材线虫差异表达基因进行GO功能富集性分析,发现1405个基因(56.16%)富集在生物过程中的24条GO-team,705个基因(28.18%)富集在细胞成分的16条GO-team,392个基因(15.67%)富集在分子功能中的10条GO-team。结果表明嗜麦芽窄食单胞菌NSPmBx03对松材线虫侵染松树后的生命活动具有一定的影响。

3. 对松材线虫差异表达基因Pathway显著性富集分析。结果表明差异表达基因主要参与的通路包括Protein digestion and absorption,Focal adhesion,Amoebiasis(Category: Infectious disease), P13K-Akt signaling pathway等。

4. 对不同处理松材线虫致病相关基因表达差异分析。结果表明嗜麦芽窄食单胞菌NSPmBx03对松材线虫细胞壁水解酶相关基因表达,谷胱甘肽s-转移酶基因和细胞色素P450等解毒相关基因表达具有一定的影响,对松材线虫卵母细胞,幼虫发育,胚胎发育,性腺,神经等生长发育相关基因的表达影响显著,且多为下调表达。

5. 通过对差异基因转录因子分类分析,发现一共有1926个差异表达基因具有编码转录因子(TF)能力,属于62个TF转录因子家族。这些差异基因主要集中在zf-C2H2(367个),Homeobox(245个),HMG(115个)等转录因子家族。

关键词:松材线虫 嗜麦芽窄食单胞菌 侵染松树 转录组测序 数据分析

Effect of bacteria in Bursaphelenchus xylophilus on gene transcriptional expression of nematode after infection

ABSTRACT

Many studies have shown that the associated-bacteria of Bursaphelenchus xylophilus play an important role in pine wilt disease (PWD). Compared with the nematode body surface bacteria, the endobacteria are less affected by the external environment and are more closely related to B. xylophilus. Therefore, it is very important to further study the role of endobacteria in the interaction between B. xylophilus and pine, and explore the intrinsic molecular mechanism. This research analyzed and validated the transcriptome data to reveal the effect of endobacteria on gene regulation of B. xylophilus in the interaction between B. xylophilus and pines. The preliminary findings were as follows:

1. After interacting with pine, there were 4240 differentially expressed genes in B. xylophilus strains treated with NSPmBx03 of S.maltophilia compared with aseptic B. xylophilus. The 1477 genes were up-regulated and 2763 genes were down-regulated. The results showed that S. maltophilia afected the gene expression of B. xylophilus.

2. GO functional enrichment analysis of differentially expressed genes of B. xylophilus showed that 1405 genes (56.16%) were enriched in 24 GO-teams in biological processes,and 705 genes (28.18%) were enriched in cells. Ingredients of 16 GO-teams, 392 genes (15.67%) were enriched in 10 GO-teams in molecular function. The results showed that S. maltophilia NSPmBx03 could influence the biology process of B. xylophilus when the nematode infected pine trees.

3. Pathway significant enrichment analysis of differentially expressed genes in B. xylophilus showed that the major pathways involved in differentially expressed genes include protein digestion and absorption, focal adhesion, amoebiasis (category: infectious disease), and p13k-akt signaling pathway.

4. Analysis of the differential expression of pathogenic genes associated with different treatments of B. xylophilus showed that S. maltophilia could affect the expression of cell wall hydrolase related genes, glutathione s-transferase genes, and cytochrome P450 detoxification-related genes. The expression of genes related to the growth and development of cells, larvae development, embryonic development, gonads, nerves, etc. were effected, and most of them were down-regulated.

5. By analyzing transcription factors (TFs) of differential genes, we found that a total of 1926 differentially expressed genes had the ability to encode transcription factors and belonged to 62 TF transcription factor families. These differential genes were mainly concentrated in transcription factor families such as zf-C2H2 (367), Homeobox (245), and HMG (115).

Key words:Bursaphelenchus xylophilusStenotrophomonas maltophilia;Pine;Transcriptome sequencing;Data analysis

目 录

1文献综述 - 1 -

1.1松材线虫病的发生和危害 - 1 -

1.2松材线虫及其伴生细菌研究进展 - 1 -

1.3植物寄生线虫转录组学的研究 - 2 -

1.4松材线虫相关基因的研究 - 4 -

1.5本研究背景及其目的意义 - 5 -

2 材料与方法 - 6 -

2.1供试松材线虫虫株、细菌菌株和松种 - 6 -

2.2松材线虫各处理样本基因差异表达分析 - 6 -

2.3松材线虫各转录本与参考基因组比对 - 6 -

2.4松材线虫各处理样本差异基因GO功能和KEGG分析 - 6 -

2.5不同处理的松材线虫差异表达基因TF编码能力预测 - 7 -

2.6不同处理的松材线虫差异表达基因蛋白互作分析 - 7 -

2.7 不同处理的松材线虫转录组数据的qRT-PCR验证 - 7 -

3 结果与分析 - 9 -

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