Abstract: Trichoderma spp. is an important biocontrol fungus resource widely distributed in nature. The colonization ability of biocontrol bacteria in host rhizosphere and its tissues is an important index to evaluate its potential of biocontrol against plant diseases. In this study, a fungiplant interaction system including Trichoderma hamatum labeled with green fluorescence protein (GFP), pepper plant and pepper Phytophthora blight fungi (Phytophthora capsici) were built. The inoculation with conidium solution of T. hamatum was carried by pouring into pepper root. Combined dualculture assay and pot experiment in greenhouse, the colonization ability of T. hamatum in pepper plants and rhizosphere soil, and its biological control against P. capsici was investigated. The results showed that T. hamatum could be colonized in root, stem, and leaf of pepper and its rhizosphere soil. In the rhizosphere soil of pepper, T. hamatum showed a dynamic colonization process. The colonization of T. hamatum increased slowly from 1 to 25 d after inoculation, and reached the highest value (700×107 conidia·g-1) gradually at 33 d after inoculation, then decreased gradually, showing a dynamic process of increasing first and then decreasing. It was revealed that T. hamatum has biological control effect on pepper Phytophthora Blight during the colonization process of T. hamatum in pepper plant and rhizosphere, the control effect is 5333%. In conclusion, T. hamatum could effectively prevent the occurrence of pepper Phytophthora Blight in field, as a beneficial fungus in microorganism of pepper rhizosphere. The present research provided a theoretical basis and effective way for the biological control of pepper Phytophthora Blight.

Key words: Trichoderma hamatum, Phytophthora capsici, biological control, colonization, rhizosphere

摘要： 木霉菌（Trichoderma spp.）是自然界广泛分布的一类重要生防真菌资源。生防菌在宿主根际及其组织中定殖能力的强弱是评价其生防潜力的重要指标。选择钩状木霉（Trichoderma hamatum）真菌、辣椒及其重要土传病害菌辣椒疫霉（Phytophthora capsici）三者互作体系，通过绿色荧光蛋白标记的钩状木霉菌株灌根接种辣椒植株，通过平板拮抗试验和温室盆栽试验，检测钩状木霉菌在辣椒植株及根际的定殖情况，及其对辣椒疫病的生物防治效果。结果表明，钩状木霉菌在辣椒根、茎和叶等组织中和辣椒根际土壤中均能够定殖。在辣椒根际土壤中，钩状木霉菌呈动态变化的定殖过程。灌根接种1～25 d，钩状木霉菌定殖量呈缓慢增长，在第33 d，达到最高值(700×107 conidia·g-1)，然后逐渐下降，呈现先增加后减少的动态变化过程。钩状木霉菌在辣椒根际和植株的定殖过程中，对辣椒疫病具有生物防治作用，防治效果达到5333％。综上，钩状木霉菌能够成为辣椒根际微生态中的有益微生物，可以有效预防辣椒疫病的发生，研究为辣椒疫病的生物防治提供了理论依据和有效途径。

关键词: 钩状木霉, 辣椒疫霉, 生物防治, 定殖, 根际土壤