玫烟色棒束孢的遗传多态性

发布时间：2018-07-29 20:52

【摘要】：玫烟色棒束孢Isaria fumosorosea在全球分布广泛,寄主多样,致病力强,是一种已开发为微生物杀虫剂的重要昆虫病原真菌,在生物防治中起着重要的作用。相同种内的不同菌株间,通常具有丰富的遗传多态性。通过对遗传多态性的研究,能从本质上揭示物种多样性的起源、变异和进化。本文将从生物学特性、致病性以及分子水平上对玫烟色棒束孢的遗传多态性进行研究,其研究结果不仅对高性能菌株的采集分离、生产育种以及生产过程中的质量监控具有理论和实践意义,而且还为今后利用该菌进行害虫的生物防治提供科学理论依据。其主要研究结果如下:1、玫烟色棒束孢的生物学特性11株所试玫烟色棒束孢菌株在不同光照条件下的宏观培养形态特征呈现极大的差异,尤其是在PDA培养基,其菌落特征差别最明显,其中产孢梗束的菌株为H3。此外,玫烟色棒束孢的分生孢子梗、瓶梗、分生孢子等显微特征、产孢量以及萌发率也显示极大差异,产孢量最多的是菌株H5,萌发率最高的是菌株H4。2、玫烟色棒束孢对二斑叶螨Tetranychus urticae的致病力玫烟色棒束孢全部所试菌株对二斑叶螨均有致死现象,不同菌株在相同浓度条件下对同一种害虫表现出不同程度的致死率。其中菌株H4表现出致死时间短、致死率高的特点。产孢量也较大,接近1.08×107个/ml,此外,菌株H8、H9和H11在产孢量与致病率方面也表现不错,半致死时间也较短,产孢量分别为0.958×107个/ml、0.82×107个/ml和0.762×107个/ml。由此看出,产孢量与致病性间存在一定的正相关性。3、基因序列分析及其与生物特性和致病性之间的相关性分析对玫烟色棒束孢进行ITS序列分析,系统发育分析表明,玫烟色棒束孢全部被试序列都分离为两个完全独立的支系,分别为聚在分支I-1中且支持率为98%的菌株和聚在分支II-1内且支持率为81%的菌株;为了确定上述两支系的真正分类地位,对所试玫烟色棒束孢与爪哇棒束孢菌株进行了多态性研究,获得7个单倍型,单倍型多样性Hd=0.605,核苷酸多样性Pi=0.04,种群遗传分化指数Fst=0.78,基因流Nm=0.07,以及2个不同的DNA序列保守区等。通过系统发育及多态性研究结果表明,将收集自国内外以及于Genbank下载的玫烟色棒束孢菌株看成一个种时,它们无论在种的水平上或假定的种群水平上,其遗传多样性都较大、分化明显,它们的差异已超出了种的边界,分支I-1中的菌株是典型的玫烟色棒束孢,而II-1中的玫烟色棒束孢菌株可能是被误定的爪哇棒束孢。对玫烟色棒束孢进行多基因序列聚类树构建,并对所试菌株(H1-H11)间进行比较,结果证明多基因树间存在一定的分支差异。其中,分支I的菌株来源相同;分支II的多数成员在PDA培养基上的菌落极厚,菌丝浓密,并且其分生孢子的萌发率都较低;菌株H2、H5和H7对二斑叶螨的致病力较低。而分支III的菌株菌落主要含孢梗束,除了H6外,其余菌株分生孢子萌发率较高,这些菌株致病性都较好,且H3与H9致病率相当,以100%支持率聚在一起。由此可见,玫烟色棒束孢对二斑叶螨致病性的高低,在分子系统树上通过聚类展示了一定的相关性。分别独立成一个分支的菌株H1、H4也无论从形态特征还是孢子萌发率方面都存在极大差异。
[Abstract]:Isaria fumosorosea, which is widely distributed worldwide, has a wide variety of host and strong pathogenicity, is an important insect pathogenic fungus developed as a microbial insecticide. It plays an important role in biological control. The genetic polymorphism is usually abundant among the different strains in the same species. In essence, it reveals the origin, variation and evolution of species diversity. This article will study the genetic polymorphism of Rosa ospora from biological characteristics, pathogenicity and molecular level. The results of this study not only have theoretical and practical significance for the collection and separation of high performance strains, production breeding and quality monitoring in the process of production. The main research results are as follows: 1, the biological characteristics of the 11 strains of Rosa colospora have great differences in the macro culture morphological characteristics under different illumination conditions, especially in the PDA medium, and their colony characteristics are poor. It is the most obvious that the strains of the pedicel bundle are H3., the microspore peduncle, the peduncle, the conidium, the sporulation and the germination rate of the spores are very different, the most spore yield is strain H5, the highest germination rate is the strain H4.2, and the pathogenicity of the two leaf mite Tetranychus urticae is the pathogenicity of the rose colospora. All the strains were lethal to the two leaf mite, and the strains of different strains showed a different degree of death to the same pest under the same concentration. Among them, the strain H4 showed a short death time and a high mortality rate. The sporulation was also large and close to 1.08 x 107 /ml. In addition, the strain H8, H9 and H11 were produced in the sporulation and the sporulation. The pathogenic rate was also good, and the half lethal time was also short, the sporulation amount was 0.958 x 107 /ml, 0.82 x 107 /ml and 0.762 x 107 /ml., thus it was found that there was a positive correlation between the sporulation and pathogenicity, and the correlation analysis between the gene sequence and the biological characteristics and pathogenicity of the ITS was carried out to ITS. Sequence analysis and phylogenetic analysis showed that all the tested sequences were separated into two completely independent branches, which were isolated in the branch I-1, with a support rate of 98%, and a strain of 81% in the branch II-1 and the support rate was 81%. 7 haplotypes, haplotype diversity Hd=0.605, nucleotide diversity Pi=0.04, population genetic differentiation index Fst=0.78, gene flow Nm=0.07, and 2 different DNA sequences conserved areas were obtained. The results of phylogenetic and polymorphism research show that the collection will be collected from home and abroad and under Genbank. At the level of species and the assumed population level, they have larger genetic diversity and distinct differentiation, and their differences have exceeded the species boundaries. The strain in the branch I-1 is a typical rose colored spore, while the Rosa colospora in II-1 may be mistaken. The multi gene sequence clustering tree was constructed for the mycelia of Romeo, and the comparison between the tested strains (H1-H11) showed that there was a certain branch difference between the multi gene trees. Among them, the strains of the branch I were the same, the majority of the members of the branch II were thick, the mycelium was thicker, and the conidium on the PDA medium. The germination rate of the strains H2, H5 and H7 was lower than that of the strains of H5 and H7, but the strains of the strains of the branch III were mainly pedicel bundles, except for the H6, the conidium germination rate of the other strains was higher, and the pathogenicity of these strains was good, and the pathogenic rate of H3 and H9 was equal, and the rate of support was together with the two spots. The pathogenicity of mites showed a certain correlation by clustering on the molecular phylogeny tree. The strain H1 was separated into one branch independently, and H4 also had great differences in morphological characteristics and spores germination rate.
【学位授予单位】：贵州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S476.12

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