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本文通过分析两种不同交配型球孢白僵菌菌株(MAT1-1-1,I型;MAT1-2-1,II型)在玉米植株中的定殖效率和回收菌株交配型基因序列的变异,拟揭示球孢白僵菌在玉米植株内生定殖过程中玉米对不同交配型菌株的选择规律、不同交配型菌株对环境的适应性能力。试验分为4个接种组,接种菌株为I型交配型菌株(Bb OFDH1-5)(处理B5)、II型交配型菌株(Bb DPSD2)(处理B2)、两个菌株等量混合(处理B5+B2)、对照组(处理CK),处理组B5、B2、B5+B2接种孢子浓度均为108孢子/m L,对照组接种量为零。结果表明,处理B5、B2、B5+B2三组中均有球孢白僵菌在玉米叶片中定殖,其中,交配型II菌株处理组B2中内生定殖效率高,检测率为33.00%;混合处理组B5+B2中交配型II菌株比I型菌株回收比率高,回收比为12:10。交配型基因序列分析显示,交配型I菌株处理组B5和混合处理组B5+B2的回收菌株中I型交配型基因非编码区序列出现多个位点突变,编码区仅在3个位点出现突变;交配型II菌株处理组B2和混合处理组B5+B2中II型交配型基因序列均没有发生变异。以上结论说明球孢白僵菌在玉米植株定殖过程中,交配型II菌株Bb DPSD2定殖率较I型菌株Bb OFDH1-5高;玉米植株更倾向于选择II型交配型菌株作为内生菌株;交配型基因MAT1-1-1比MAT1-2-1更易发生突变表明I型菌株对自然环境的适应性更强。
In this paper, we analyzed the colonization efficiency of maize plants from two different mating type strains of Beauveria bassiana (MAT1-1-1, type I; MAT1-2-1, type II) and the variation of mate-mating gene sequences , It is to be revealed Beauveria bassiana maize plant endogenous colonization in the mating process of different mating strains of law, different mating strains of adaptability to the environment. The experiment was divided into four inoculation groups, the inoculated strains were type I mating type strain (Bb OFDH1-5) (treatment B5), type II mating type strain (Bb DPSD2) (treatment B2), and the two strains were mixed in equal amounts + B2), and CK (control group), the spores concentration of the treated groups B5, B2, B5 + B2 were all 108 spores / m L, and the inoculum size of the control group was zero. The results showed that Beauveria bassiana was colonized in maize leaves in the treatments B5, B2 and B5 + B2, and the endophytic colonization rate in mating type II strain B2 was high, with the detection rate of 33.00% ; Mixed treatment group B5 + B2 mating type II strains than the type I strain recovery rate, the recovery ratio was 12:10. Mating type gene sequence analysis showed that there were several site mutations in the non-coding region of the type I mating gene in the reclaimed strains of the mating type I strain B5 and the mixed treatment group B5 + B2, and the coding region appeared only at three sites Mutations; Type II mating type gene sequences in mating type II strain B2 and mixed treatment group B5 + B2 did not mutate. The above conclusions indicate that during the colonization of corn plants, the colonization rate of mating type II strain Bb DPSD2 is higher than that of type I strain Bb OFDH1-5. The maize plants are more likely to select type II mating strains as endophytic strains Mating gene MAT1-1-1 is more susceptible to mutation than MAT1-2-1, indicating that type I strains are more adaptive to the natural environment.