title: Estimates of biomechanical forces in Magnaporthe grisea.
abstract: The mechanical actions of the fungus Magnaporthe grisea raise many intriguing questions concerning the forces involved. These include: (1) the material properties of the appressorial wall; (2) the strength of the adhesive that keeps the appressorium anchored to the rice leaf surface; and (3) the forces involved in the penetration process whereby a peg is driven through the host cell wall. In this paper we give order of magnitude estimates for all three of these quantities. A simple Young-Laplace law type argument is used to show that the appressorial wall elastic modulus is of order 10-100 MPa; and an adaptation of standard adhesion theory indicates a lower bound on the strength of the appressorial adhesive to be of the order 500 J/m(2). Drawing on ideas from plasticity theory and ballistics, estimates of the penetration force raise interesting questions about experiments performed on the penetration of inert substrates by the fungus.
authors.affiliation: Program in Applied Mathematics and Department of Mathematics, University of Arizona, Tucson, AZ 85721, USA. goriely@math.arizona.edu <goriely@math.arizona.edu>
authors.forename: Alain
authors.initials: A
authors.lastname: Goriely
authors.forename: Michael
authors.initials: M
authors.lastname: Tabor
mesh_terms: D001696:Biomechanical Phenomena; D002448:Cell Adhesion; D002473:Cell Wall / Q000382:microbiology / Q000502:physiology; D004548:Elasticity; D025301:Hyphae / Q000502:physiology; D020082:Magnaporthe / Q000166:cytology / Q000378:metabolism / Q000472:pathogenicity*; D008543:Melanins; D008954:Models, Biological; D012275:Oryza / Q000382:microbiology*; D011312:Pressure
chemical_list: D008543:Melanins