title: Identification of a locus controlling Verticillium disease symptom response in Arabidopsis thaliana.
abstract: Verticillium dahliae Klebahn is a soil-borne fungal pathogen causing vascular diseases. The pathogen penetrates the host through the roots, spreads through the xylem, and systemically colonizes both resistant and susceptible genotypes. To elucidate the genetic and molecular bases of plant-Verticillium interactions, we have developed a pathosystem utilizing Arabidopsis thaliana and an isolate of V. dahliae pathogenic to both cruciferous and non-cruciferous crops. Relative tolerance (based on symptom severity) but no immunity was found in a survey of Arabidopsis ecotypes. Anthocyanin accumulation, stunting, and chlorosis were common symptoms. Specific responses of the more susceptible ecotype Columbia were induction of early flowering and dying. The more tolerant ecotype C-24 was characterized by pathogen-induced delay of transition to flowering and mild chlorosis symptoms. Genetic analysis indicated that a single dominant locus, Verticillium dahliae-tolerance (VET1), likely functioning also as a negative regulator of the transition to flowering, was able to convey increased tolerance. VET1 was mapped on chromosome IV. The differential symptom responses observed between ecotypes were not correlated with different rates of fungal tissue colonization or with differential transcript accumulation of PR-1 and PDF1.2 defense genes whose activation was not detected during the Arabidopsis-V. dahliae interaction. Impairment in salicylic acid (SA)- or jasmonic acid (JA)-dependent signaling did not cause hypersensitivity to the fungal infection, whereas ethylene insensitivity led to reduced chlorosis and ABA deficiency to reduced anthocyanin accumulation. The results of this study clearly indicated that the ability of V. dahliae to induce disease symptoms is also connected to the genetic control of development and life span in Arabidopsis.
authors.affiliation: Center for Plant Environmental Stress Physiology, 625 Agriculture Mall Drive, Purdue University, West Lafayette, IN 47907-2010, USA.
authors.forename: Paola
authors.initials: P
authors.lastname: Veronese
authors.forename: Meena L
authors.initials: ML
authors.lastname: Narasimhan
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Stevenson
authors.forename: Jian-K
authors.initials: JK
authors.lastname: Zhu
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Weller
authors.forename: Krishna V
authors.initials: KV
authors.lastname: Subbarao
authors.forename: Ray A
authors.initials: RA
authors.lastname: Bressan
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D017360:Arabidopsis / Q000235:genetics* / Q000254:growth & development / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology; D023082:Defensins / Q000235:genetics / Q000378:metabolism; D005030:Ethylenes / Q000494:pharmacology; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000382:microbiology; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D005799:Genes, Dominant / Q000235:genetics; D007113:Immunity, Innate / Q000187:drug effects / Q000235:genetics; D054883:Oxylipins; D010935:Plant Diseases / Q000382:microbiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D020156:Salicylic Acid / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D020172:Verticillium / Q000254:growth & development*
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D023082:Defensins; D005030:Ethylenes; D054883:Oxylipins; D010940:Plant Proteins; C077262:PR-1 protein, Arabidopsis; C011006:jasmonic acid; D000040:Abscisic Acid; C036216:ethylene; D020156:Salicylic Acid