Fine Structures and Electron Microscopy

  • Govind Singh Saharan
  • Naresh K. Mehta
  • Prabhu Dayal Meena


The formation of fine structures of powdery mildew pathogens during infection and pathogenesis after artificial inoculation of Arabidopsis have been revealed through light, and scanning electron microscopy (SEM). The sequence of events has been observed from time of inoculation to production of asexual states, and symptoms production on the host leaf, and stem. The comparative observations on the morphological characteristics of different structures formed by three pathogens viz., Erysiphe cruciferarum, E. orontii, and E. cichoracearum of Arabidopsis have been distinguished as a compatible host-parasite interaction system for molecular and genetical studies. The observations have been recorded on pathogens hypha, its branches, angles; mycelium growth; conidiophore shape, size, number of conidia formed; conidial shape, size; germ tubes number, shape, its tips shape; haustoria, its shape; number of infection pegs, their shape; appressoria, their shape, and formation of papillae. For each event, time period has been recorded including incubation period of powdery mildew pathogens on Arabidopsis. The fine structures revealed through SEM such as septa, haustorial sac, extra haustorial membrane, vacuolar membrane of the host cell, host cytoplasm, granular structures in the extra haustorial matrix, space between the haustorial sac, and haustorium, and haustorial lobes are very crucial to understand the mechanisms of pathogenesis by powdery mildews of crucifers in susceptible, and resistant hosts. The observations of encapsulation of haustoria, formation of papilla like structures, deposition of granular material adjacent to haustoria, and necrosis of host cells are potential resistant reactions of the invaded host plant. Now a day, SEM observations have become important and essential criteria for all taxon of powdery mildews especially when only anamorph states are produced like in powdery mildews of Arabidopsis.


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Copyright information

© Springer Nature Singapore Pte Ltd. 2019

Authors and Affiliations

  • Govind Singh Saharan
    • 1
  • Naresh K. Mehta
    • 1
  • Prabhu Dayal Meena
    • 2
  1. 1.Department of Plant PathologyCCS Haryana Agricultural UniversityHisarIndia
  2. 2.Crop Protection Unit, ICAR-Directorate of Rapeseed-Mustard ResearchBharatpurIndia

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