Structure Root colonization

Changes in cell-wall protein composition may regulate the molecular architecture of protein networks in a manner that allows new developmental outcomes for both fungal cell adhesion and root colonization. Further investigation of the structure and regulation of SRAP wall proteins will provide a more complete picture of their role in developing ectomycorrhizal tissues. Incompatibility between ectomycorrhizal hyphae and the host roots detected during the initial con-... 

Endomycorrhizal hyphae adopt a variety of colonization patterns in their penetration of the host root cells. Glomalean fungi are highly dependent on their ho.st and cannot survive for long in its absence. Their hyphae form appressoria on the epidermal cells, penetrate the cortical tissue, and eventually form highly branched structures called arbuscules (Figs. 3-6) (10). 

The importance of including soil-based parameters in rhizosphere simulations has been emphasized (56). Scott et al. u.sed a time-dependent exudation boundary condition and a layer model to predict how introduced bacteria would colonize the root environment from a seed-based inoculum. They explicitly included pore size distribution and matric potential as determinants of microbial growth rate and diffusion potential. Their simulations showed that the total number of bacteria in the rhizosphere and their vertical colonization were sensitive to the matric potential of the soil. Soil structure and pore size distribution was also predicted to be a key determinant of the competitive success of a genetically modified microorganism introduced into soil (57). The Scott (56) model also demonstrated that the diffusive movement of root exudates was an important factor in determining microbial abundance. Results from models that ignore the spatial nature of the rhizosphere and treat exudate concentration as a spatially averaged parameter (14) should therefore be treated with some caution. 

In contrast with the numerous free-living nematodes, some plant-pathogenic nematodes spend most of their life inside plant roots or on their surface in cysts and/or root knots. These resting structures persist in the soil and act as a selective substratum for fungal colonization by egg parasites. Certain clavicipitaceous anamorphs, now comprised in the genus Pochonia (Zare et al.,... 

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