Pathogens exert mechanical force to enter plants through openings or weak points on the plant. Fungi and oomycetes enter through wounds, applying mechanical pressure, or secreting enzymes. Nematodes adhere through suction and use their stylet, exerting back-and-forth thrust, to penetrate cells. Bacteria enter through natural openings like stomata or wounds.

2. MECHANICAL FORCE EXERTED BY
PLANT PATHOGENS
SHAHID SIDDIQUE
+923008998805
Department of plant pathology
University of Agriculture, Faisalabad
2018

3. Introduction
• Pathogen ---attack to acquire substances necessary for
survival.
• Mostly present in protoplast of host cell.
• Overcome barriers--- cuticle /cell wall, defense
systems etc.
• Pathogen enter the plant cell through mechanically
(Specialized organs ) or chemically (Enzymes).

4. Conti….

5. How Pathogens Enter…..????
• Bacteria --- mostly enter through natural
openings(Stomata etc) as well as wounds, cuts etc.
• Nematode --- Stylet to gain entry.
• Fungi and Oomycetes---wounds, mechanical
pressure or through enzymes they secreates etc.
• Virus or Viroids---require vectors

6. Steps…
• Landing
• Adherence
• Germination
• Penetration

7. Fungus

8. Nematode
•Adherence---suction (fuse lips).
•Stylet--- exert mechanical pressure through back & forth
thrust.
•Stylet move forward and rear body rotate slowly.