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Screening and Identification of Marine-derived Fungi Having Antifungal Activity on Plant Pathogens

Author: XuLanLan
Tutor: LiKunZhi；HuangShuShi
School: Kunming University of Science and Technology
Course: Botany
Keywords: Marine fungus Antibacterial activity Plant pathogenic fungi Filter Appraisal
CLC: S476.1
Type: Master's thesis
Year: 2010
Downloads: 90
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Abstract

Very unique marine microbial ecology of the marine and terrestrial microorganisms produce different metabolic systems and defense systems, extracted from marine microorganisms bioactive substances often have novel chemical structure and specific physiological functions, in recent years, is widely used in biological control regard, the development of agricultural antibiotics has become a new way. Current international research and development of marine microbial resources are mainly concentrated in the coastal waters. This article from the northern Gulf coastal mangrove areas Seabed Area collected and water samples, separation shallow microorganisms screened for activity against plant pathogenic strains, and activity of microbial strains of physiological and biochemical characteristics and ITS sequences, etc. conducted a preliminary research, in order to further the development of biocontrol agents against plant diseases and basic parameters provide active strains. Manhole from Qinzhou Port Beibu Gulf coastal waters and stove river mud and seawater samples collected more than three times, and isolated from marine fungi. Phytophthora litchi cream, lychee anthracnose, rice blast fungus Rhizoctonia solani and as indicator bacteria were screened first by plate confrontation strains with antibacterial activity, and then prepare its fermentation broth through inhibition of mycelial growth method rescreening, determine its antibacterial activity. Then select the antibacterial activity of several strains of bacteria were fermented liquid antibacterial litchi postharvest experiments validate its practical application. Then through the salt tolerance test test whether they are strictly marine microorganisms, and further by morphological observation and ITS gene sequence determination, on which representative strains for molecular identification and phylogenetic analysis, and finally determine its species. The results show that the experiments were isolated from 64 marine fungi. Through one of the 14 marine fungi for screening, access to 13 with anti-fungal activity of plant pathogenic strains, the most obvious of which 020103,020204,020102 antibacterial effect. Strong antibacterial activity in which you select for rescreening of 10, all strains against Rhizoctonia solani mycelium growth was inhibited. Of which 010,104 pairs of Rhizoctonia solani best inhibitory effect, reaching 71 percent. To rice blast fungus for indicator bacteria occurs when two kinds of situations: First, the fermentation broth inhibited the growth of indicator bacteria, a total of four, the proportion was 40%; Second fermentation broth for the growth of indicator bacteria play a catalytic role in the proportion was 60%. Of which 010,104 pairs of rice pathogen Pyricularia oryzae best inhibitory effect, reaching 61 percent. Most strains fermented liquid litchi cream Phytophthora mycelial growth inhibition, including 020,202 pairs of litchi cream inhibitory effect of Phytophthora best mycelial growth inhibition rate of 93%, followed by 020,103 and 010,104, bacteria mycelial growth inhibition rate of 86% and 71%. Inhibitory effect on litchi anthracnose 020103 is the best mycelial growth inhibition was 55% relative. Select the antibacterial activity and colony characteristics representative strains 5, numbered 010104,020205,020202,020102,020103, its antibacterial test litchi harvest results showed that under normal temperature fermentation broth of several marine fungus processed fruit browning index of less than fungicide treatments, including 020,102 strains of the best. 010104 fermentation broth litchi anthrax have some effect. Through strains morphology, molecular identification and phylogenetic analysis, five marine fungi identification results were as follows: 020,103 is Bray Eupenicillium (Eupenicillium brefeldianum), 010104 is janthinellum (Penicillium janthinellum), 020205 is A Daqing mold (Penicillium adametzii), 020102 is oxalicum (Penicillium oxalicum), 020202 is the rod Aspergillus (Aspergillus clavatonanicus).

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