| Objective: In order to clear and definite the species that pathogen of jujube fruit shrink and jujube black spot in Xinjiang,analyzed the mycotoxins species and content of the mainly pathogen,and selected representative strains to conduct pathogenicity tests.The results of the experiments provide theoretical basis and technical support for the prevention and control of jujube black spot.Methods: The samples with jujube fruit shrink disease and jujube black spot were collected from jujube mainly cultivation areas in Xinjiang.These samples were isolated and purified.pathogenicity tests of isolates were carried out by inoculation in vitro.The isolates were then identified through the method of morphological and molecular biology(rDNA-ITS,EF-1?,?-tubulin and Actin sequence analysis).After that,representative strains were used to analyzed the mycotoxins species and content by the way of Utra-performance liquid chromatography-tandem mass spectrome-try.Finally,the pathogenicity of the crude toxin were analyzed.Results:1.The experiment used 95 jujube samples with fruit shrink disease and 77 samples with black spot.The samples were collected from important jujube production areas near Hami,Asku,and the Bayingolin Mongol Autonomous Prefecture.A total of 90 isolates were obtained from samples exhibiting jujube fruit shrink disease and 49 isolates from samples with jujube black spot.Among the 139 isolates,there were 131 strains(94.25%)of Alternaria alternata,6 strains(4.32%)of Fusarium,and 2 strains(1.44%)of Penicillium.The results of pathogenicity test showed that Alternaria caused jujube fruit disease,and Alternaria was the mainly pathogen of these two kinds of disease.2.According to the morphological features of culture and the gene sequences analysis of rDNA-ITS,Actin,?-tubulin,and EF-1?,the pathogen of jujube fruit shrink disease and jujube black spot was identified as Alternaria alternate(fries)Keissler.3.Utra-performance liquid chromatography-tandem mass spectrome-try had been established as the method to analyze the species and content of mycotoxins which from the 10 Alternaria strains and the onset fruit of jujube black spot in different severity and artificial inoculation fruit.The results showed that 10 A.alternaria strains can produce 4 kinds of Alternaria mycotoxins which are alternariol(AOH),alternariol monomethyl-ether(AME),altenuene(ALT)and tenuazonic acid(TeA).TeA,ALT,AME and AOH were detected in different disease onset of jujube and artificial cultivation conditions.The highest content was TeA,range of 3.1×103~5.5×103mg/kg,AME,AOH and ALT were 0.6~6.4×102mg/kg,1.2~3.8×102mg/kg and 0.09~5.08mg/kg.The main pathogens(Alternaria alternate)causing jujube fruit shrink and jujube black spot can produced a lot of Alternaria mycotoxins,which have such great influence on the production and value of jujube.4.Pathogenicity tests of Alternaria toxin was conducted on the chlorophyll content,cell membrane permeability,enzyme activities and soluble sugar content of jujube leaves.The results showed that the content of chlorophyll a was about 22?g/m L which had no significant changes,but the total content of chlorophyll and the content of chlorophyll b were decreased.The permeability of cell membrane increased with the extension of treatment time,and the membrane permeability increased from 821?s/cm to 1686?s/cm;CAT and POD decreased significantly.The activity of MDA decreased,strain 92-3-1 was the lowest reduced for 5.54U/mgprot.The content of sucrose,fructose and glucose increased slightly,while the content of soluble sugar increased remarkably. |
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