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First published online March 18, 2005; 10.1104/pp.104.056366 Plant Physiology 137:1363-1374 (2005) © 2005 American Society of Plant Biologists
Tissue-Specific Localization of Pea Root Infection by Nectria haematococca. Mechanisms and Consequences1Division of Plant Pathology and Microbiology, Department of Plant Sciences, University of Arizona, Tucson, Arizona 85721 (U.G., M.R., H.D.V., M.C.H.); Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742 (D.S.); and Department of Biology, University of South Florida, Tampa, Florida 33620 (J.T.R.)
Root infection in susceptible host species is initiated predominantly in the zone of elongation, whereas the remainder of the root is resistant. Nectria haematococca infection of pea (Pisum sativum) was used as a model to explore possible mechanisms influencing the localization of root infection. The failure to infect the root tip was not due to a failure to induce spore germination at this site, suppression of pathogenicity genes in the fungus, or increased expression of plant defense genes. Instead, exudates from the root tip induce rapid spore germination by a pathway that is independent of nutrient-induced germination. Subsequently, a factor produced during fungal infection and death of border cells at the root apex appears to selectively suppress fungal growth and prevent sporulation. Host-specific mantle formation in response to border cells appears to represent a previously unrecognized form of host-parasite relationship common to diverse species. The dynamics of signal exchange leading to mantle development may play a key role in fostering plant health, by protecting root meristems from pathogenic invasion.
1 This work was supported by the U.S. Department of Agriculture (grants awarded to M.C.H.). 2 Present address: Diversa, San Diego, CA 92121. Article, publication date, and citation information can be found at www.plantphysiol.org/cgi/doi/10.1104/pp.104.056366. * Corresponding author; e-mail mhawes{at}u.arizona.edu; fax 5206219290. Received November 19, 2004; returned for revision February 15, 2005; accepted February 19, 2005. This article has been cited by other articles:
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