RCH1, a Locus inArabidopsisThat Confers Resistance to the Hemibiotrophic Fungal PathogenColletotrichum higginsianum

Abstract

When challenged with the crucifer pathogen Colletotrichum higginsianum, Arabidopsis thaliana ecotype Columbia (Col-0) was colonized by the fungus within 2 to 3 days, developing brown necrotic lesions surrounded by a yellow halo. Lesions spread from the inoculation site within 3 to 4 days, and subsequently continued to expand until they covered the entire leaf. Electron microscopy confirmed that C. higginsianum is a hemibiotroph on Arabidopsis, feeding initially on living cells as a biotroph before switching to a necrotrophic mode of growth. A collection of 37 ecotypes of Arabidopsis varied in their responses to infection by C. higginsianum. The ecotype Eil-0 was highly resistant, with symptoms limited to necrotic flecking and with only very limited fungal colonization. Analyses suggested that the hypersensitive response and reactive oxygen species may be important in this defense response. Expression analyses with cDNA microarrays indicated that the defense reaction depends primarily on the jasmonic acid- and ethylene-dependent signaling pathways and, to a lesser extent, on the salicylate-dependent pathway. Crosses between the Eil-0 and Col-0 ecotypes suggested that the resistance in Eil-0 was dominant and was conferred by a single locus, which we named RCH1. RCH1 is the first resistance locus to be identified from Arabidopsis against the hemibiotrophic fungus genus Colletotrichum.

Leaf Oil Body Functions as a Subcellular Factory for the Production of a Phytoalexin in Arabidopsis

“…Development of CLO3-and a-DOX1-Positive Oil Bodies in Perilesional Areas of Leaves Infected with C. higginsianum Infection of C. higginsianum, which is pathogenic to Arabidopsis (Narusaka et al, 2004;O'Connell et al, 2004), resulted in the formation of lesions on leaves 4 d after infection. CLO3 mRNA began to accumulate 4 d after infection with C. higginsianum, and the levels increased significantly within 7 d ( Fig.…”

“…Recently, the genus Colletotrichum genome and transcriptome were analyzed (O'Connell et al, 2012). An isolate of Colletotrichum higginsianum has been reported to infect Arabidopsis (Arabidopsis thaliana; Narusaka et al, 2004;O'Connell et al, 2004). The use of model plants enabled the characterization of the interaction between the fungus and Arabidopsis plants in the infected area (Narusaka et al, 2009;Hiruma et al, 2010Hiruma et al, , 2011.…”

Entry Mode–Dependent Function of an Indole Glucosinolate Pathway in Arabidopsis for Nonhost Resistance against Anthracnose Pathogens

“…Isolates of Colletotrichum higginsianum infect Arabidopsis (O'Connell et al, 2004;Narusaka et al, 2004), which provides a new model pathosystem between Arabidopsis and Colletotrichum in which both partners in the interaction can be genetically manipulated. We previously reported that nonhost resistance of Arabidopsis against Colletotrichum species largely depends on preinvasion immune responses that act at the cell periphery (Shimada et al, 2006).…”

A model system to screen for candidate plant activators using an immune-induction system in Arabidopsis

“…A total of 1.2 K potential biotic and abiotic stressrelated genes were selected from the genes covered by the Arabidopsis 7 K array (RIKEN, Japan) and Arabidopsis oligo microarray (Agilent Technologies, USA) for this study (Seki et al 2002;Narusaka et al 2003a;2003b;2004a;2004b;. To gain further information on the characterization of plant activators in the defense response, we studied their effect on the expression of the 1.2 K stress-related genes in our microarray.…”

“…Full-length cDNA microarray analysis was carried out essentially as reported previously (Seki et al 2001;Narusaka et al 2003a;2003b;2004a;2004b;. Arabidopsis wild-type plants (ecotype Columbia; Col-0) were grown in soil for 28 days in a growth chamber at 22°C under a 12-h light/12-h dark cycle.…”