玉米内生链格孢多样性及其生态功能研究

发布时间：2018-01-07 03:04

本文关键词：玉米内生链格孢多样性及其生态功能研究　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：内生真菌一般指那些在其生活史的某一阶段或者整个生活史生长于植物体内,不引起宿主明显病症的真菌,其与植物的长期协同进化中,形成了一种复杂、特殊的关系,可以互惠共生,也可能是潜在病原菌,或者是潜在兼性腐生菌。链格孢属真菌广泛存在于自然界,能引起多种农作物病害。链格孢也是大量植物的优势内生真菌,但目前对于内生链格孢属真菌生活史及生态功能了解较少。通过对玉米优势内生真菌链格孢的研究,对阐明内生链格孢属真菌与宿主的相互关系,了解内生链格孢生活史和生态功能,以及指导玉米耕作栽培具有重要意义。本实验对实验室分离保存的玉米内生链格孢真菌进行分析,表明内生链格孢在玉米体内的分布具有广泛性及多样性,对10个代表性形态型的菌株基于rDNA-ITS序列进行系统发育分析,均与小孢子种类聚在一起,通过ITS序列无法进行种级区分。通过形态学鉴定,10株链格孢均为小孢子种链格孢,初步鉴定:Y1为A.alternata,Y4为A.catalpae,Y5与Y6归入A.tenuissima species-group,Y8为A.peponicola,Y9为A.ellisii,Y10为A.platycodonis,Y11归入A.alternata species-group,Y12为A.triticimaculans,Y13为A.coicis。通过溶磷能力检测、对玉米生长发育的影响、降解能力初步探讨了玉米内生链格孢真菌生态功能,并且以一株产酶能力最强的菌株为研究对象,进行了某些生物学特性研究。在溶磷试验中,10株链格孢菌均不能在PVK平板上形成透明圈,初步判断其不具备溶磷作用。10株菌对玉米发芽率,苗期的株高、茎粗及根长均无显著性影响。通过对玉米接种内生链格孢菌株,发现10株内生链格孢菌株对苗期玉米无致病性。而在与4种玉米病原菌的平板对峙试验中,10株链格孢菌对4种玉米病原菌均显示出抑制作用,其中菌株Y6对玉米禾谷镰刀菌的抑菌率最高,达到了69.01%;菌株Y13对玉米大斑菌的抑制效果最好,达68.05%;菌株Y12对玉米圆斑抑制率达53.18%;菌株Y8对玉米弯孢菌的抑制率为67.03%。通过对10株链格孢菌株产纤维素酶、漆酶活性和对玉米秸秆的降解能力研究,发现链格孢属内生真菌具有一定的腐生能力。通过革兰氏碘液平板、愈创木酚及苯胺蓝平板筛选,10株链格孢均能产纤维素酶及漆酶,不具有锰过氧化物酶及木质素过氧化物酶活性。通过纤维素酶活及漆酶酶活测定,菌株Y13的纤维素酶及漆酶活力均最高,以菌株Y13为代表,进行玉米秸秆降解实验,实验组秸秆失重率在10天、20天、30天分别为22%、34.7%、41.2%,高于对照组的10%、11.7%及12.5%,表明菌株Y13对秸秆有较好的降解力。研究菌株Y13在不同碳、氮源下的生长情况,结果表明,菌株Y13的最佳碳、氮源分别是麦芽糖、乳糖及蛋白胨。菌株Y13在不同碳、氮源下产漆酶能力有显著差异,在碳源为麦芽糖及乳糖时产漆酶活力最高,氮源为蛋白胨时漆酶活力最高,与菌株生长的最适碳、氮源一致。通过上述研究,发现玉米内生链格孢属真菌均属于小孢子类群,但在形态、生理和遗传上有一定的差异。玉米内生链格孢在玉米生长发育期,作为内生真菌存在于植物体内,可能会增强玉米对病原菌的抗性;玉米内生链格孢可产生纤维素酶及相关酶类,可以降解玉米秸秆,在内生菌阶段结束后,可以腐生方式继续生活。本研究对阐明内生链格孢属真菌生态学功能,指导玉米耕作栽培和病害防治,以及对内生链格孢菌的资源开发与利用具有重要意义。
[Abstract]:Endophytic fungi generally refers to those who are in a stage of their life cycle or the life cycle of growth in the plant, do not cause obvious symptoms of host plants and fungi, the long-term coevolution, forming a complex and special relationship, can mutualism, may also be potential pathogens, or potential facultative saprophyte. Alternaria fungi widely exists in the nature, can cause various crop diseases. Alternaria is a large number of plant dominant endophytic fungi, but the endophytic fungi of the genus Alternaria life history and ecological function are poorly understood. Through research on Maize dominant endophytic fungi Alternaria, for clarifying the relationship between endophytic fungus Alternaria and host endophytic Alternaria, understand the life history and ecological function, as well as the guidance of corn cultivation is of great significance. This experiment on laboratory separation and preservation of corn endophytic Alternaria Analysis of fungal spore, indicated that endophytic Alternaria has universality and diversity in the distribution of maize, 10 representative strains based on morphological type rDNA-ITS sequence for phylogenetic analysis, and microspore species together, through the ITS to a level sequence. Through morphological identification, 10 strains all kinds of microspore of Alternaria Alternaria, preliminary identification: Y1 A.alternata, Y4 A.catalpae, Y5 and Y6 in A.tenuissima species-group, Y8 A.peponicola, Y9 A.ellisii, Y10 A.platycodonis, Y11 A.alternata Y12 A.triticimaculans in species-group, Y13, A.coicis. through the ability of phosphate detection effect on maize growth and development the preliminary study on degradation ability of corn endophytic Alternaria fungi ecological function, and to a strain of the enzyme producing ability strongest strains as the research object, studied some biological characteristics. Soluble phosphorus test, 10 strains of Alternaria alternata were not on the PVK panel to form a transparent circle, it does not have to determine the initial phosphate solubilization of.10 strains on the germination rate of maize seedling, plant height, stem diameter and root length had no significant effect on maize. Through inoculation endophytic Alternaria strain. 10 strains of endophytic Alternaria strains had no pathogenicity to the maize plant. In the plate confrontation test with 4 kinds of maize pathogenic bacteria, 10 strains of Alternaria on 4 maize pathogens showed inhibitory effects of Y6 on Maize strains of Fusarium graminearum highest inhibition rate reached 69.01%. The inhibitory effect of Y13 strains; exserohilumturcicum bacteria best, 68.05%; inhibition of strain Y12 on Maize round spot rate reached 53.18%; strain Y8 inhibition of Maize Curvularia rate for 67.03%. by 10 strains of Alternaria strains producing cellulase, laccase activity and degradability of corn straw, the chain genus Endophytic fungi have certain saprophytic ability. Through gram iodine tablet, screening of guaiacol and aniline blue plate, 10 strains producing cellulase and laccase were Alternaria, with manganese peroxidase and lignin peroxidase activity. The activity determination of cellulase activity and laccase enzyme, cellulase and laccase activity of strain Y13 were the highest, the strain Y13, degradation experiment of corn straw, straw weight loss rate in the experimental group for 10 days, 20 days, 30 days were 22%, 34.7%, 41.2%, higher than the control group 10%, 11.7% and 12.5%, showed that strain Y13 had better degradation of straw. The strain Y13 in different carbon growth, nitrogen source, the results showed that the best carbon strain Y13, nitrogen source was maltose, lactose and peptone. Strain Y13 in different carbon and nitrogen sources under laccase significantly, laccase activity was maltose and lactose in carbon source The highest nitrogen source was peptone when the highest laccase activity, the optimum carbon and nitrogen source for strain growth, consistent. The above results showed that the maize endophytic Alternaria fungi belong to the microspore groups, but there are some differences in morphology, physiology and genetics. Corn endophytic Alternaria spore growth period in maize, exists in plants as endophytic fungi could increase maize resistance to pathogens; corn endophytic Alternaria can produce cellulase and related enzymes, degradation of corn straw, the endogenous bacteria after the end of the stage, can continue to live saprophytic. This study of endophytic Alternaria fungal ecology function, corn cultivation and disease prevention, and resource development and utilization of endophytic Alternaria has important significance.

【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S513

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