Signaling for Growth Orientation and Cell Differentiation by Surface Topography in Uromyces

Abstract

The dimensions of the topographical signals for growth orientation and infection structure formation, a cell differentiation event that includes nuclear division, were determined for the stomatal penetrating rust fungus Uromyces appendiculatus. The differentiation signal was found to be a simple ridge on the substrate surface that had a markedly optimum height of 0.5 micrometer. Such ridges were microfabricated on silicon wafers by using electron-beam lithography. A similar ridge, in the form of a stomatal lip, was found associated with the stomatal guard cells of the bean (Phaseolus vulgaris) leaf. Ridge elevations greater than 1.0 micrometer or less than 0.25 micrometer did not serve as effective signals. Germ tubes of the fungus were highly oriented by ridge spacings of 0.5 to 6.7 micrometers. The data indicate that the fungus is able to distinguish uniquely minute differences in leaf surface topography in order to infect the host plant.

Filamentous growth of Candida albicans in response to physical environmental cues and its regulation by the unique CZF1 gene

“…The plant pathogen, Uromyces appendiculatus, the bean rust fungus, responds to the physical characteristics of its environment by undergoing cellular differentiation (Hoch et al, 1987). Arti®cial substrates containing 0.5 mm ridges promoted the production of appressoria, structures that are normally formed over stomates during infection of a bean leaf.…”

Fungal Morphogenesis

“…Cells in the hyphal form are inherently more effective in penetrating physical barriers and expanding colony growth three-dimensionally. Hyphae are also more likely to show gravitropism, thigmotropism, phototropism, aerotropism, and galvanotropism (Hoch et al 1987;Crombie et al 1990;Moore 1991;Moore et al 1996;Aoki et al 1998; Figure 2. C. neoformans Rac2 localization suggests a role in cell polarity.…”

Biology on a Chip: Microfabrication for Studying the Behavior of Cultured Cells

“…For example, Pins et al 5 made microtextured layers of collagen or gelatin (replicated from a PDMS mold that was in turn replicated from a laser-micromachined epoxy mold) to simulate the basal lamina of the skin; keratinocytes formed a Differentiated and stratified epidermis that conformed to the surface of the membrane, and stratification in the deeper channels was enhanced compared to the shallower channels or the fl at inter-channel regions, suggesting that part of the skin growth and Differentiation program is governed by surface topography. In 1987, Hoch et al 291 used microfabrication methods to simulate plant infection by spores, which were shown to grow using topographical guidance cues. Wheeler and colleagues 292,293 have been able to manipulate single mammalian embryos through a network of microfluidic channels to manipulate the extracellular environment.…”