酵母拮抗菌形态转变对逆境耐受性和生防效力的影响研究

发布时间：2018-01-08 06:12

本文关键词：酵母拮抗菌形态转变对逆境耐受性和生防效力的影响研究　出处：《合肥工业大学》2017年硕士论文　论文类型：学位论文

【摘要】：近年来,利用生物拮抗菌防治植物病害已被证明是替代化学杀菌剂的安全有效措施之一。采用自然存在于果蔬表面的酵母菌作为拮抗菌是控制果蔬采后病害的新方法之一。而对酵母拮抗菌生物学特性的研究是了解其生物防治机理的前提。相关研究发现,当特定的酵母菌达到一定种群密度时,其在特定的介质表面上会产生群体效应由单细胞转变为生物膜形态(由胞外多聚物基质包围形成的结构群落)。本课题以两种能够发生形态变化的生防酵母拮抗菌Pichia kudriavzevii和Pichia cecembensis为实验材料,研究了生防酵母菌形态变化对其抗逆性、胞内抗氧化酶活性、逆境下细胞损伤程度、种群繁殖速度及生防效力的影响。通过研究发现:(1)生防酵母菌P.kudriavzevii和P.cecembensis在由单细胞形态转变为生物膜形态后其抗逆性增强,在逆境条件下存活率更高;(2)生防酵母菌P.kudriavzevii和P.cecembensis在生物膜形态下细胞内抗氧化酶Catalase、Super Oxide Dismutase和Glutathione peroxidase的活性更高,在经过逆境处理后细胞内Malondialdehyde和Carbonyl积累量显著低于单细胞形态;(3)生物膜形态的生防酵母菌P.kudriavzevii相比于其自身单细胞形态在梨果实伤口处具有更快的生长繁殖速度;而生物膜形态的生防酵母菌P.cecembensis在苹果果实伤口处具有更快的生长繁殖速度;(4)生防酵母菌P.kudriavzevii在生物膜形态时相比于其自身单细胞形态对梨果实灰霉病和炭疽病的防治效果更佳;而生物膜形态的酵母菌P.cecembensis则对苹果果实青霉病防治效果更佳。上述研究结果表明,酵母菌P.kudriavzevii和P.cecembensis在发生形态转变后其生防效力增强,对特定水果采后病害具有更好的防治效果。这可能是由于酵母菌在生物膜形态时胞内抗氧化酶活性更高,逆境条件下细胞损伤更小、存活率更高,能够更好地适应环境,在果实表皮伤口的微观不利环境下快速繁殖,先一步占领生存空间、消耗营养物质,从而抑制了病原菌的生长,达到了更好的防治效果。
[Abstract]:In recent years. The control of plant diseases by biological antagonistic bacteria has been proved to be one of the safe and effective measures to substitute chemical fungicides. It is a new method to control postharvest diseases of fruits and vegetables by using yeast which naturally exists on the surface of fruits and vegetables as antagonistic bacteria. The study of biological characteristics of yeast antagonistic bacteria is the premise of understanding its biological control mechanism. When a specific yeast reaches a certain population density. It produces a population effect on the surface of a particular medium from a single cell to a biofilm shape (a structural community surrounded by an extracellular polymer matrix). In this study, two biocontrol yeast antagonists, Pichia kudriavzevii and Pichia cecembensis, were used as experimental materials. The effects of morphological changes of biological control yeast on its resistance to stress, intracellular antioxidant enzyme activity and the degree of cell damage under stress were studied. Effects of population Reproduction rate and Biocontrol effectiveness. The resistance of P. kudriavzevii and P.cecembensis to biofilm was enhanced after the transformation from single cell morphology to biofilm morphology. The survival rate was higher under adverse conditions. (2) the biocontrol yeast P.kudriavzevii and P.cecembensis had an antioxidant enzyme Catalase in the biofilm. The activities of Super Oxide Dismutase and Glutathione peroxidase were higher. The accumulation of Malondialdehyde and Carbonyl was significantly lower than that of single cell after stress treatment. (3) the biofilm form of P. kudriavzevii has a faster growth and reproduction rate than its own single cell morphology in the cut of pear fruit, and the growth rate of P. kudriavzevii is higher than that of P. kudriavzevii. The biocontrol yeast P.cecembensis in the form of biofilm had a faster growth and reproduction rate in the apple fruit wound. (4) the biocontrol effect of P. kudriavzevii was better than that of its own single cell morphology in the control of grey mold and anthracnose of pear fruit. But the biofilm-like yeast P.cecembensis had better control effect on apple fruit penicillium. The biocontrol effect of P. kudriavzevii and P.cecembensis increased after morphological transformation. This may be due to the higher activity of intracellular antioxidant enzymes in the biofilm morphology, the less cell damage and the higher survival rate under stress. It can better adapt to the environment, rapidly propagate in the microcosmic unfavorable environment of fruit epidermis wound, occupy the living space first, consume nutrients, thus inhibit the growth of pathogenic bacteria, and achieve better control effect.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TS255.3;TQ926

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