Host entry requires plant pathogens to breach the protective surface of the plant. Phytophthora species, classified as oomycetes, are among the most destructive filamentous plant pathogens worldwide and pose a substantial threat to food security. Little is known about the biomechanics of host invasion in oomycetes, yet this understanding is crucial to combat these pathogens more effectively. Here we unveil how Phytophthora spp. invade elastic surfaces by pressure application at an oblique angle without appressorium formation. This ‘slicing’ action, coined the naifu-mechanism, facilitates crack initiation by concentrating stresses towards the surface enabling host entry through the crack void. This contrasts the ‘brute’ force approach found in fungal filamentous plant pathogens capable of producing a melanized appressorium that generates tremendous turgor pressures. Measurements of surface deformations during invasion reveal an asymmetric geometry of decoupled adherence and indentation sites that is quantitatively described with a mathematical model. Moreover, we establish how polarized growth, surface adherence and turgor generation are each essential to accomplish host entry by this approach. The naifu-mechanism enables Phytophthora pathogens to penetrate their hosts without necessitating specialized pressure organs and vast turgor pressures.
|Date made available||22 Mar 2021|
|Publisher||Wageningen University & Research|
|Temporal coverage||2018 - 2021|