Abstract

Histological investigations elucidate infection structure development and the subsequent colonization process of rust pathogens in their cereal hosts. No comprehensive information exists for the infection process of the wheat stem rust fungus, Puccinia graminis f. sp. tritici (Pgt), on triticale, an amphiploid species carrying both the wheat and rye genomes. The adult plant stem rust response of the triticale cultivars ‘Kiewiet’, ‘Coorong’ and ‘Satu’ and the bread wheat control, Line 37–07, was determined under controlled conditions using Pgt pathotypes UVPgt56, UVPgt60 and UVPgt62. Flag leaf sheaths were sampled 24 and 48 h post-inoculation (hpi) for scanning electron microscopy (SEM), 120 hpi for fluorescence microscopy, and 16 days post-inoculation for a fungal biomass assay. Although slight differences were observed between the epidermal morphology of triticale and wheat stem sheaths, SEM results indicated that this did not influence early infection by Pgt. Fluorescence microscopy revealed that colony size was affected by both host genotype and pathotype. Colony size strongly corresponded with fungal biomass accumulation, except in ‘Kiewiet’, where fungal growth was not restricted to the same degree as in other incompatible interactions. This study shows that methods commonly used for studying histopathology of Pgt in wheat are equally applicable to triticale.

摘要

组织学研究阐明了锈病病原体在其谷物宿主中的感染结构发展和随后的定植过程。没有关于小麦茎锈病菌Puccinia graminis f感染过程的综合信息。sp. 小麦（PGT），小黑麦上，承载小麦和黑麦的基因组两者二倍体物种。小黑麦品种“Kiewiet”的成株茎锈病响应，“枯荣”和“萨图马雷”和面包小麦控制，37-07行，用受控条件下测定PGT病理型 UVPgt56、UVPgt60 和 UVPgt62。在接种后 24 和 48 小时 (hpi) 对旗叶鞘进行采样以进行扫描电子显微镜 (SEM)，在 120 hpi 进行荧光显微镜检查，并在接种后 16 天进行真菌生物量测定。尽管在小黑麦和小麦茎鞘的表皮形态之间观察到了细微的差异，但扫描电镜结果表明这并不影响Pgt 的早期感染。荧光显微镜显示集落大小受宿主基因型和病理型的影响。菌落大小与真菌生物量积累密切相关，除了在“Kiewiet”中，真菌生长不受其他不相容相互作用相同程度的限制。本研究表明，研究Pgt组织病理学的常用方法 在小麦中同样适用于小黑麦。