向日葵核盘菌致病力分化及菌核形成机制的研究

发布时间：2018-06-11 14:08

本文选题：核盘菌 + 致病力分化　；参考：《内蒙古农业大学》2016年博士论文

【摘要】：向日葵菌核病是由核盘菌(Sclerotinia sclerotiorum)引起的向日葵生产过程中的主要病害,对世界各地的向日葵生产造成了很大的损失。本研究通过对内蒙古巴彦淖尔市五原县、宁夏石嘴山市惠农区和新疆博尔塔拉蒙古自治州温泉县三个地区采集的向日葵核盘菌的致病力分化、药剂敏感性、核盘菌菌核的形成过程以及cAMP和生防菌S-16、 CF4-51抑制菌核形成的机制进行了研究,得到如下结论：1.内蒙古巴彦淖尔市五原县、宁夏石嘴山市惠农区和新疆博尔塔拉蒙古自治州温泉县三地的向日葵核盘菌均有致病力分化的情况；三地均存在一定比例的弱致病力菌株。2.室内药剂敏感性测定的实验结果表明在新疆供试的核盘菌菌株中存在一定比例对多菌灵有抗药性的菌株。3.向日葵核盘菌菌核的形成是从菌丝体单个细胞的分化开始的,而不是菌丝体互相缠绕,聚集而形成。4.H202在核盘菌菌核形成过程中起重要的作用。只有当菌丝体内H202含量高至一定水平时,核盘菌才能由营养菌丝生长阶段转变到菌核形成的Initial阶段。5.核盘菌菌丝细胞内cAMP的浓度是影响核盘菌菌核形成的关键因素。当菌丝细胞内cAMP浓度增加时,会抑制Noxl和Nox2基因的相对表达量,使得菌丝体细胞内H202浓度降低,进而使得菌核的形成受到抑制。cAMP不仅通过调控H202的积累调控菌核从营养生长向菌核形成起始阶段的转变,同时在菌核从起始阶段向菌核成熟阶段的转化过程中也起着一定的调控作用。6.枯草芽孢杆菌S-16不仅能够使核盘菌营养菌丝生长异常,而且还抑制菌核的形成；S-16菌株通过调控Ac相对表达量,使得核盘菌内部cAMP的浓度增加,进而负向的调控Noxl和Nox2的表达,使得菌丝体内H202含量显著降低,最终影响核盘菌菌核的形成。7.蜡状芽孢杆菌CF4-51可使核盘菌营养菌丝异常生长；CF4-51通过正向调控Sod和Cat的相对表达量,进而使得SOD和CAT的酶活性增强,从而降低了菌丝体细胞中的H202水平,导致菌核的形成受到抑制。
[Abstract]:Sunflower sclerotinia sclerotiorum (Sclerotinia sclerotiorum) is the main disease in sunflower production, which has caused great losses to sunflower production all over the world. The pathogenicity differentiation and drug sensitivity of Sclerotinia solanum collected from Wuyuan County of Bayan Nur City Ningxia Shizuishan Huinong District and Wenquan County of Bortala Mongolia Autonomous Prefecture of Xinjiang were studied in this study. The formation process of Sclerotinia sclerotiorum and the mechanism of camp and biocontrol bacteria S-16, CF4-51 inhibiting sclerotia formation were studied. The conclusions are as follows: 1. In Wuyuan County, Shizuishan City, Ningxia, and in Wenquan County, Bortala Mongol Autonomous Prefecture, Inner Mongolia, Inner Mongolia has pathogenicity differentiation of sunflower sclerotia, and there is a certain proportion of weak pathogenicity strains. The results of laboratory drug sensitivity test showed that there was a certain proportion of strains resistant to carbendazim. 3 among the strains of Sclerotinia sclerotiorum tested in Xinjiang. The formation of the sclerotia of Sclerotinia sclerotiorum began from the differentiation of single mycelium cells, but not from the twining and aggregation of mycelium to form .4.H202, which played an important role in the formation of sclerotia of Sclerotinia sclerotiorum (Sclerotinia sclerotiorum). Only when the content of H202 in mycelium reached a certain level could Sclerotinia sclerotiorum change from vegetative hyphae growth stage to initial stage of sclerotia formation. The concentration of camp in the mycelium of Sclerotinia sclerotiorum was the key factor affecting the formation of sclerotia. When the concentration of camp in mycelium cells increased, the relative expression of Noxl and Nox2 genes was inhibited, which decreased the concentration of H202 in mycelia cells. Thus, the formation of sclerotia was inhibited. Camp not only regulated the transformation of sclerotia from vegetative growth to sclerotia formation by regulating the accumulation of H202. At the same time in the sclerotia from the initial stage to the sclerotia maturation stage of the transformation process also plays a certain role in the regulation. 6. Bacillus subtilis S-16 not only caused the abnormal growth of vegetative hyphae of Sclerotinia sclerotiorum, but also inhibited the formation of sclerotia. By regulating the relative expression of ac, the concentration of camp in Sclerotinia sclerotiorum increased, and the expression of Noxl and Nox2 was regulated negatively. The content of H 202 in mycelium was significantly decreased, and the formation of sclerotia was affected. Bacillus cereus CF4-51 can increase the relative expression of sod and Cat through positive regulation of the relative expression of sod and cat, thus reducing the level of H202 in mycelium cells. The formation of sclerotia was inhibited.
【学位授予单位】：内蒙古农业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S435.655

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