title: Root Border Cells and Their Role in Plant Defense.
abstract: Root border cells separate from plant root tips and disperse into the soil environment. In most species, each root tip can produce thousands of metabolically active cells daily, with specialized patterns of gene expression. Their function has been an enduring mystery. Recent studies suggest that border cells operate in a manner similar to mammalian neutrophils: Both cell types export a complex of extracellular DNA (exDNA) and antimicrobial proteins that neutralize threats by trapping pathogens and thereby preventing invasion of host tissues. Extracellular DNases (exDNases) of pathogens promote virulence and systemic spread of the microbes. In plants, adding DNase I to root tips eliminates border cell extracellular traps and abolishes root tip resistance to infection. Mutation of genes encoding exDNase activity in plant-pathogenic bacteria (Ralstonia solanacearum) and fungi (Cochliobolus heterostrophus) results in reduced virulence. The study of exDNase activities in plant pathogens may yield new targets for disease control.
authors.affiliation: Department of Soil, Water and Environmental Sciences, Bio5 Institute, University of Arizona, Tucson, Arizona 85721; email: mhawes@email.arizona.edu , curlango@email.arizona.edu , dahuskey@email.arizona.edu.
authors.forename: Martha
authors.initials: M
authors.lastname: Hawes
authors.affiliation: Department of Plant Pathology, University of Wisconsin, Madison, Wisconsin 53706; email: callen@wisc.edu , tuantran2904@gmail.com.
authors.forename: Caitilyn
authors.initials: C
authors.lastname: Allen
authors.affiliation: School of Integrative Plant Science, Plant Pathology & Plant-Microbe Biology Section, Cornell University, Ithaca, New York 14853; email: bgt1@cornell.edu.
authors.forename: B Gillian
authors.initials: BG
authors.lastname: Turgeon
authors.affiliation: Department of Soil, Water and Environmental Sciences, Bio5 Institute, University of Arizona, Tucson, Arizona 85721; email: mhawes@email.arizona.edu , curlango@email.arizona.edu , dahuskey@email.arizona.edu.
authors.forename: Gilberto
authors.initials: G
authors.lastname: Curlango-Rivera
authors.affiliation: Department of Plant Pathology, University of Wisconsin, Madison, Wisconsin 53706; email: callen@wisc.edu , tuantran2904@gmail.com.
authors.forename: Tuan
authors.initials: T
authors.lastname: Minh Tran
authors.affiliation: Department of Soil, Water and Environmental Sciences, Bio5 Institute, University of Arizona, Tucson, Arizona 85721; email: mhawes@email.arizona.edu , curlango@email.arizona.edu , dahuskey@email.arizona.edu.
authors.forename: David A
authors.initials: DA
authors.lastname: Huskey
authors.affiliation: School of Plant Science, Bio5 Institute, University of Arizona, Tucson, Arizona 85721; email: zxiong@email.arizona.edu.
authors.forename: Zhongguo
authors.initials: Z
authors.lastname: Xiong
mesh_terms: D001203:Ascomycota / Q000235:genetics / Q000502:physiology; D018519:Meristem / Q000276:immunology / Q000382:microbiology; D010935:Plant Diseases / Q000276:immunology* / Q000382:microbiology; D057865:Plant Immunity; D018517:Plant Roots / Q000276:immunology* / Q000382:microbiology; D043368:Ralstonia solanacearum / Q000235:genetics / Q000502:physiology
keywords: exDNA; exDNase; extracellular traps; rhizosphere; root cap slime