Phytopathology. 2014 Aug;104(8):820-33. doi: 10.1094/PHYTO-11-13-0316-R.
This study was designed to characterize and describe host cell responses of stem tissue to mango wilt disease caused by the fungus Ceratocystis fimbriata in Brazil. Disease progress was followed, through time, in inoculated stems for two cultivars, 'Ubá' (field resistant) and 'Haden' (field susceptible). Stem sections from inoculated areas were examined using fluorescence light microscopy and transmission and scanning electron microscopy, coupled with energy-dispersive X-ray microanalysis. Tissues from Ubá colonized by C. fimbriata had stronger autofluorescence than those from Haden. The X-ray microanalysis revealed that the tissues of Ubá had higher levels of insoluble sulfur and calcium than those of Haden. Scanning electron microscopy revealed that fungal hyphae, chlamydospores (aleurioconidia), and perithecia-like structures of C. fimbriata were more abundant in Haden relative to Ubá. At the ultrastructural level, pathogen hyphae had grown into the degraded walls of parenchyma, fiber cells, and xylem vessels in the tissue of Haden. However, in Ubá, plant cell walls were rarely degraded and hyphae were often surrounded by dense, amorphous granular materials and hyphae appeared to have died. Taken together, the results of this study characterize the susceptible and resistant basal cell responses of mango stem tissue to infection by C. fimbriata.
本研究旨在对巴西由真菌 Ceratocystis fimbriata 引起的芒果枯萎病的干细胞组织的宿主细胞反应进行特征描述。通过对两个品种（‘Ubá’（田间抗性）和‘Haden’（田间敏感））接种茎的时间进程进行跟踪，观察到了疾病的进展。使用荧光显微镜、透射电子显微镜和扫描电子显微镜以及能量色散 X 射线微分析对接种区域的茎段进行了检查。与 Haden 相比，被 C. fimbriata 定殖的 Ubá 组织具有更强的自发荧光。X 射线微分析显示，Ubá 组织中的不溶性硫和钙含量高于 Haden。扫描电子显微镜显示，与 Ubá 相比，Haden 中真菌菌丝、厚垣孢子（粉孢子）和 C. fimbriata 的子囊壳状结构更为丰富。在超微结构水平上，病原菌菌丝已长入 Haden 组织中退化的薄壁组织、纤维细胞和木质部导管的细胞壁中。然而，在 Ubá 中，植物细胞壁很少被降解，菌丝常被密集的无定形颗粒物质包围，菌丝似乎已经死亡。综上所述，本研究的结果描绘了芒果茎组织对 C. fimbriata 感染的敏感和抗性基础细胞反应。
