Resistance in mango against infection by Ceratocystis fimbriata

• Published in: Phytopathology Vol. 104; no. 8; pp. 820 - 833
• Main Authors: Araujo, Leonardo, Bispo, Wilka Messner Silva, Cacique, Isaías Severino, Moreira, Wiler Ribas, Rodrigues, Fabrício Ávila
• Format: Journal Article
• Language: English
• Published: United States 01-08-2014
• Subjects: Ascomycota - pathogenicity; Ascomycota - physiology; Ascomycota - ultrastructure; Brazil; Cell Wall - ultrastructure; Ceratocystis fimbriata; Disease Resistance; Electron Probe Microanalysis; Hyphae; Mangifera - immunology; Mangifera - microbiology; Mangifera - ultrastructure; Mangifera indica; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Microscopy, Fluorescence; Plant Diseases - immunology; Plant Diseases - microbiology; Plant Stems - immunology; Plant Stems - microbiology; Plant Stems - ultrastructure; Spores, Fungal; Time Factors; Xylem - immunology; Xylem - microbiology; Xylem - ultrastructure; Brazil; phenolic-like compounds; barrier zones; vascular pathogen
• ISSN: 0031-949X; 1943-7684
• 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.