立枯丝核菌(Rhizoctonia solani)对日本结缕草(Zoysia japonica steud.)的侵染过程研究

【目的】了解立枯丝核菌(Rhizoctonia solani) AG1 IA对日本结缕草(Zoysia japonica steud.)的侵染过程及其引起的病害症状，为进一步从分子水平研究该菌的病理学侵染机制和草坪草抗病分子育种提供理论基础。【方法】通过根部接种法促使立枯丝核菌与日本结缕草无菌苗建立侵染关系，从而对其病叶率、病株率及病情指数进行统计分析，同时结合组织染色透明技术及植物组织石蜡切片对立枯丝核菌的侵染过程、感染方式进行研究。【结果】立枯丝核菌AG1 IA的侵染过程主要为：菌丝吸附在植物组织表面，并沿组织表面定向生长，形成侵染结构——侵染垫与组织建立密切的侵染关系。菌丝通过细胞间隙侵入植物组织内部，主要侵染植物皮层细胞及除木质部导管以外的整个维管束系统。结缕草的地上部分与地下部分组织对立枯丝核菌的侵染显现不同的寄主反应。【结论】立枯丝核菌的侵染过程主要包括吸附、定向生长、渗透、定殖4个部分；立枯丝核菌的侵染主要引起结缕草叶片病症；结缕草病变与菌丝直接侵染无直接联系，表明该菌具有复杂的侵染机制。

The infection process of Rhizoctonia solani in Zoysia japonica

[Objective] In order to figure out the infection relationship between Rhizoctonia solani AG1 IA and Zoysia japonica, and provide a theoretical basis for further research on pathological infection mechanism, as well as molecular breeding for disease resistance of turfgrass. [Methods] Z. japonica was infected by R. solani AG1 IA through root inoculation, the disease incidence of leaves and plants, disease index were analyzed. Meanwhile, the infection process and methods was studied using histological staining transparent technology and paraffin sections. [Results] The hyphae of R. solani AG1 IA hyphae firstly adsorbed, and then grew directionally along the surface of the tissue, followed by the formation of infection cushion. The hyphae penetrated the tissues through intercellular spaces and invaded the cortical cells, and gradually extended inward the vascular system except xylem vessels. The underground and ground part of Z. japonica showed disparate host response against R. solani AG1 IA. [Conclusion] Infection process of R. solani include adsorption, directional growth, penetration, colonization. The infection of R. solani mainly cause Z. japonica leaves lesions. There are no direct correlation between Z. japonica lesions and infecting hyphae. This might indicate that R. solani has the complex mechanism of pathogenicity.