The arabidopsis TIR-NB-LRR gene RAC1 confers resistance to Albugo candida (white rust) and is dependent on EDS1 but not PAD4.
Resistance to Albugo candida isolate Acem1 is conferred by a dominant gene, RAC1, in accession Ksk-1 of Arabidopsis thaliana. This gene was isolated by positional cloning and is a member of the Drosophila toll and mammalian interleukin-1 receptor (TIR) nucleotide-binding site leucine-rich repeat (NB-LRR) class of plant resistance genes. Strong identity of the TIR and NB domains was observed between the predicted proteins encoded by the Ksk-1 allele and the allele from an Acem1-susceptible accession Columbia (Col) (99 and 98%, respectively). However, major differences between the two predicted proteins occur within the LRR domain and mainly are confined to the beta-strand/beta-turn structure of the LRR. Both proteins contain 14 imperfect repeats. RAC1-mediated resistance was analyzed further using mutations in defense regulation, including: pad4-1, eds1-1, and NahG, in the presence of the RAC1 allele from Ksk-1. White rust resistance was completely abolished by eds1-1 but was not affected by either pad4-1 or NahG.
Borhan
Mohammad H
MH
Agriculture and Agri-Food Canada, Saskatoon Research Center, Saskatoon, SK., S7N 0X2, Canada.
Holub
Eric B
EB
Beynon
Jim L
JL
Rozwadowski
Kevin
K
Rimmer
S Roger
SR
D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D002265:Carboxylic Ester Hydrolases / Q000235:genetics* / Q000378:metabolism; D018244:Chromosomes, Artificial, Yeast; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D007113:Immunity, Innate / Q000235:genetics; D008969:Molecular Sequence Data; D009868:Oomycetes / Q000254:growth & development; D010935:Plant Diseases / Q000235:genetics / Q000382:microbiology; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology
D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; C118837:EDS1 protein, Arabidopsis; C489522:RAC1 protein, Arabidopsis; D002265:Carboxylic Ester Hydrolases; C400766:PAD4 protein, Arabidopsis